Patent-Eligible Subject Matter Reform: Background and Issues for Congress

Patent-Eligible Subject Matter Reform:
December 1, 2022
Background and Issues for Congress
Kevin J. Hickey
The statutory definition of patent-eligible subject matter under Section 101 of the Patent Act has
Legislative Attorney
Background and Issues for Congress Updated March 31, 2025 (R45918) Jump to Main Text of Report

Contents

• Patent Law Background
• Requirements for Patentability
• Section 101: Utility
• Section 102: Novelty
• Section 103: Nonobviousness
• Section 112(a): Written Description, Enablement, Best Mode
• Patent Claims
• Section 112(b): Definiteness
• Section 112(f): Functional Claiming
• Rights of Patent Holders
• Defending Against Patent Suits
• The Law of Section 101
• Historical Development of the Judicial Exceptions to Patent-Eligible Subject Matter
• Nineteenth Century
• Twentieth Century
• The Modern Alice/Mayo Framework
• The Debate Over Alice/Mayo and Section 101 Reform
• Criticisms of the Alice/Mayo Framework
• Defenses of the Alice/Mayo Framework
• Views on the Purposes of Section 101
• Potential Options for Section 101 Reform
• Continued Common Law Judicial Development
• Specific Statutory List of Included or Excluded Subject Matter Categories
• Replace Judicial Exceptions with a Different Standard
• Eliminate Implied Patentable Subject Matter Limits
• Post-Alice Developments in Patent-Eligible Subject Matter Law and Proposed Reforms
• Judicial Developments
• Administrative Developments in the USPTO
• The 2019 Revised Patent Subject Matter Eligibility Guidance
• 2022 USPTO Report on Stakeholder Views
• 2024 Artificial Intelligence Eligibility Guidance
• Legislative Developments
• The 116th Congress
• The 117th Congress
• The 118th Congress
• Conclusion

Tables

• Table 1. Major Supreme Court Decisions on Patentable Subject Matter

Summary

The statutory definition of patent-eligible subject matter under Section 101 of the Patent Act (35 U.S.C. § 101) has remained essentially unchanged for more than two centuries. As a result, the scope of patentable remained essentially unchanged for more than two centuries. As a result, the scope of patentable

subject matter—that is, the types of inventions that may be patented—has largely been left to the subject matter—that is, the types of inventions that may be patented—has largely been left to the
federal courts to develop through federal courts to develop through “"common lawcommon law”"-like adjudication. In the 20th century, the U.S. -like adjudication. In the 20th century, the U.S.

Supreme Court established that three main types of discoveries are categorically patent-Supreme Court established that three main types of discoveries are categorically patent-
ineligibleineligible when claimed as such: laws of nature, natural phenomena, and abstract ideas.: laws of nature, natural phenomena, and abstract ideas.
A series of Supreme Court decisions in the 2010s broadened the scope of these three judicial exceptions to patent-eligible A series of Supreme Court decisions in the 2010s broadened the scope of these three judicial exceptions to patent-eligible
subject matter. Over a five-year period, the Supreme Court rejected, as ineligible, patents on a business method for hedging subject matter. Over a five-year period, the Supreme Court rejected, as ineligible, patents on a business method for hedging
price-fluctuation riskprice-fluctuation risk; a method for calibrating the dosage of a particular drug; isolated human DNA segments (Bilski v. Kappos, 561 U.S. 593 (2010)); a method for calibrating the dosage of a particular drug (Mayo Collaborative Services v. Prometheus Laboratories, 566 U.S. 66 (2012)); isolated human DNA segments (Ass'n for Molecular Pathology v. Myriad Genetics, Inc., 569 U.S. 576 (2013)); and a method ; and a method
of mitigating settlement risk in financial transactions using a computerof mitigating settlement risk in financial transactions using a computer (Alice Corp. Pty. v. CLS Bank International, 573 U.S. 208 (2014)). These cases established a new two-step test, known . These cases established a new two-step test, known
as the as the Alice//Mayo framework, for determining whether a patent claims ineligible subject matter. framework, for determining whether a patent claims ineligible subject matter.
The first step of the The first step of the Alice//Mayo test addresses whether the patent claims are test addresses whether the patent claims are “"directed todirected to”" a law of nature, natural a law of nature, natural
phenomenon, or abstract idea. If not, the invention is patentable. If the claims are directed to one of the ineligible categories, phenomenon, or abstract idea. If not, the invention is patentable. If the claims are directed to one of the ineligible categories,
then the second step of the then the second step of the analysisAlice/Mayo test asks whether the patent claims have an asks whether the patent claims have an “"inventive concept.inventive concept.”" To have an inventive To have an inventive
concept, the patent claim must contain elements that transform the nature of the claim into a patent-eligible application of the concept, the patent claim must contain elements that transform the nature of the claim into a patent-eligible application of the
ineligible concept, so that the claim amounts, in practice, to something ineligible concept, so that the claim amounts, in practice, to something “"significantly moresignificantly more”" than a patent on the ineligible than a patent on the ineligible
concept itself. If the concept itself. If the invention fails the second step of Alice/Mayoclaimed invention lacks an inventive concept, then it is patent-ineligible., then it is patent-ineligible.
The Supreme CourtThe Supreme Court’'s decisions have been widely recognized to effect a major change in the scope of patentable subject s decisions have been widely recognized to effect a major change in the scope of patentable subject
matter, restricting the sorts of inventions that are patentable in the United States. The matter, restricting the sorts of inventions that are patentable in the United States. The Alice//Mayo test has been the subject of test has been the subject of
criticism, with some stakeholders arguing that the criticism, with some stakeholders arguing that the Alice//Mayo framework is vague and unpredictable, unduly restricts the framework is vague and unpredictable, unduly restricts the
scope of patentable subject matter, reduces incentives to invest and innovate, and harms American industryscope of patentable subject matter, reduces incentives to invest and innovate, and harms American industry’s
's competitiveness. In particular, competitiveness. In particular, these stakeholders argue that the the Alice//Mayo test test has createdcreates uncertainty in the computer technology and biotechnology uncertainty in the computer technology and biotechnology
industries as to whether innovations in medical diagnostics, personalized medicine, methods of treatment, computer software, industries as to whether innovations in medical diagnostics, personalized medicine, methods of treatment, computer software,
and artificial intelligence are patent-eligible. and artificial intelligence are patent-eligible.
As a result, some patent lawSuch stakeholders—including academics, bar associations, industry representatives, judges, and stakeholders—including academics, bar associations, industry representatives, judges, and
former former U.S. Patent and Trademark Office (Patent and Trademark Office (PTOUSPTO) officials—have called for the Supreme Court or Congress to act to change the ) officials—have called for the Supreme Court or Congress to act to change the
law of patentable subject matter. law of patentable subject matter. Other stakeholders defend the legal status quo, arguing that the Other stakeholders defend the legal status quo, arguing that the Alice//Mayo framework framework
provides an important tool for combating unmeritorious patent litigation, or that the revitalized limits on patentable subject provides an important tool for combating unmeritorious patent litigation, or that the revitalized limits on patentable subject
matter have important benefits for innovation. matter have important benefits for innovation.
Recently, there have been several substantialFor example, some civil liberty and nonprofit organizations generally support the Alice/Mayo framework, which they argue helps foster invention and innovation by preventing monopolies on basic research tools and concepts. The past decade has seen a number of judicial, administrative, and legislative developments in patent-eligible subject judicial, administrative, and legislative developments in patent-eligible subject
matter law and potential reformsmatter law and potential reforms responding to the Alice/Mayo decisions. On the judicial front, the Supreme Court has declined to hear further cases on . On the judicial front, the Supreme Court has declined to hear further cases on thisthe topic, topic,
despite calls by prominent stakeholders and judges on the U.S. Court of Appeals for the Federal Circuit. despite calls by prominent stakeholders and judges on the U.S. Court of Appeals for the Federal Circuit. In 2019, the PTO
issued and updated its guidanceOn the administrative front, the USPTO issued updated guidance in 2019 and 2024 to clarify and improve predictability in how to clarify and improve predictability in how PTOUSPTO patent examiners make Section 101 patent examiners make Section 101
determinations, and determinations, and in 2022 issued a new report on the topic. Following a series of hearings on the topic and draft legislative
proposals in the 116th Congress, the 117th Congress saw several introduced bills seeking to reform the statutory standard for
patentable subject matter.
released several reports on the topic. In Congress, several bills introduced in the 117th and 118th Congresses would have abrogated the Supreme Court's recent decisions on patent-eligible subject matter and otherwise reformed the statutory standards for patent-eligible subject matter. Proposed changes to patent-eligible subject matter standards could have significant effects as to the types of technologies that Proposed changes to patent-eligible subject matter standards could have significant effects as to the types of technologies that
are patentable. The availability of patent rights, in turn, affects incentives to invest and innovate in particular fields, as well as are patentable. The availability of patent rights, in turn, affects incentives to invest and innovate in particular fields, as well as
consumer costs and public access to technological innovation. Understanding the legal background and context of this consumer costs and public access to technological innovation. Understanding the legal background and context of this
complex issue may aid Congress as it debates the legal and practical effects that legislative Section 101 reforms would have complex issue may aid Congress as it debates the legal and practical effects that legislative Section 101 reforms would have
if enacted.

Congressional Research Service

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Contents
Patent Law Background .................................................................................................................. 4
Requirements for Patentability .................................................................................................. 5
Section 101: Utility ............................................................................................................. 5
Section 102: Novelty........................................................................................................... 5
Section 103: Nonobviousness ............................................................................................. 6
Section 112(a): Written Description, Enablement, Best Mode ........................................... 6
Patent Claims ............................................................................................................................ 7
Section 112(b): Definiteness ............................................................................................... 7
Section 112(f): Functional Claiming ................................................................................... 7
Rights of Patent Holders ........................................................................................................... 9
Defending Against Patent Suits ............................................................................................... 10
The Current Law of Section 101 .................................................................................................... 11
Historical Development of the Judicial Exceptions to Patent-Eligible Subject Matter ........... 13
Nineteenth Century ........................................................................................................... 13
Twentieth Century ............................................................................................................. 14
The Modern Alice/Mayo Framework ...................................................................................... 16
The Debate Over Alice/Mayo and Section 101 Reform ................................................................ 21
Criticisms of the Alice/Mayo Framework ............................................................................... 21
Defenses of the Alice/Mayo Framework ................................................................................. 23
Potential Rationales for Section 101 ....................................................................................... 25
Potential Options for Section 101 ........................................................................................... 26
Continued Common Law Judicial Development .............................................................. 27
Specific Statutory List of Included or Excluded Subject Matter Categories .................... 28
Replace Judicial Exceptions with a Different Standard .................................................... 29
Eliminate Implied Patentable Subject Matter Limits ........................................................ 30
Recent Developments in Patent-Eligible Subject Matter Reform ................................................. 30
Judicial Developments ............................................................................................................ 30
Administrative Developments: PTO Subject Matter Eligibility Guidance ............................. 32
Legislative Developments in the 116th Congress ................................................................... 35
The First Tillis-Coons Proposal ........................................................................................ 35
The Second Tillis-Coons Proposal .................................................................................... 36
Legislative Developments in the 117th Congress ................................................................... 39
The Patent Eligibility Restoration Act of 2022 ................................................................. 39
The Restoring America’s Leadership in Innovation Act of 2021 ..................................... 40
Conclusion ..................................................................................................................................... 40

Tables
Table 1. Major Supreme Court Decisions on Patentable Subject Matter ...................................... 18

Contacts
Author Information ........................................................................................................................ 41

Congressional Research Service

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link to page 8 Patent-Eligible Subject Matter Reform

he statutory language governing patent-eligible subject matter—that is, the types of
inventions that may be patented—has remained remarkably constant over the nearly 250-
T year history of U.S. patent law.1 Under the Patent Act of 1793, which Thomas Jefferson
authored,2 “any new and useful art, machine, manufacture or composition of matter, or any new
and useful improvement [of the same]” was patentable.3 Current law—Section 101 of the Patent
Act of 1952—permits the patenting of “any new and useful process, machine, manufacture, or
composition of matter, or any new and useful improvement thereof.”4 Through these four
expansive statutory categories,5 Congress sought to ensure that nearly “anything under the sun
made by man” is patentable6 if it meets all the requirements for patentability, such as novelty,
enablement, and nonobviousness.7
Consistent with its broad statutory language, Section 101 permits patenting in fields of applied
technology such as pharmaceuticals, biotechnology, chemistry, computer hardware and software,
electrical engineering, agriculture, mechanical engineering, and manufacturing processes.8 Even
so, the Supreme Court has long read Section 101 as categorically prohibiting patents on three
types of discoveries: “laws of nature, natural phenomena, and abstract ideas.”9 Even if “not
required by the statutory text” of Section 101, the Court has held that these three judicial

1if enacted. The statutory language governing patent-eligible subject matter—that is, the types of inventions that may be patented—has remained remarkably constant over the nearly 250-year history of U.S. patent law.¹ Under the Patent Act of 1793, which Thomas Jefferson authored,² "any new and useful art, machine, manufacture or composition of matter, or any new and useful improvement [of the same]" was patentable.³ Current law—Section 101 of the Patent Act of 1952—permits the patenting of "any new and useful process, machine, manufacture, or composition of matter, or any new and useful improvement thereof."⁴ Through these four expansive statutory categories,⁵ Congress sought to ensure that nearly "anything under the sun made by man" is patentable⁶ if it meets all the requirements for patentability, such as novelty, enablement, and nonobviousness.⁷

Consistent with its broad statutory language, Section 101 permits patenting in fields of applied technology such as pharmaceuticals, biotechnology, chemistry, computer hardware and software, electrical engineering, agriculture, mechanical engineering, and manufacturing processes.⁸ Even so, the Supreme Court has long read Section 101 as categorically prohibiting patents on three types of discoveries: "laws of nature, natural phenomena, and abstract ideas."⁹ Even if "not required by the statutory text" of Section 101, the Court has held that these three judicial exceptions "define[] the reach of the statute as a matter of statutory stare decisis going back 150 years."¹⁰

In a series of decisions in the 2010s, the Supreme Court relied on Section 101 to reject patent claims on

• a method for hedging price-fluctuation risks in commodity markets;¹¹
• a method for measuring metabolites in human blood to calibrate the dosage of particular drug;¹²
• isolated human DNA segments;¹³ and
• a method of mitigating settlement risk in financial transactions using a computer.¹⁴

These cases established a two-step test for patentable subject matter sometimes called the "Alice/Mayo test" or the "Alice/Mayo framework."¹⁵ The Court's decisions have been widely recognized to effect a major change in the scope of patentable subject matter, restricting the sorts of inventions that are patentable in the United States.¹⁶ The Alice/Mayo framework has thus shifted, for better or worse, the balance between encouraging innovation and the social costs of exclusive rights that is at the heart of patent law.¹⁷ The effects of this change have been particularly pronounced for computer technologies and biomedical technologies.¹⁸ As a result, there is a significant and ongoing debate about the Alice/Mayo framework, with a number of patent law stakeholders questioning the Court's patentable subject matter rulings.¹⁹ Critics argue that the Alice/Mayo framework is vague, unpredictable, and not administrable;²⁰ muddies patent law by confusing patent eligibility with distinct patent law concerns, such as nonobviousness;²¹ reduces incentives to innovate and invest in particular industries, such as biotechnology;²² or puts U.S. industry at a disadvantage with international competitors.²³ Other stakeholders defend the Alice/Mayo framework, arguing that the Court's decisions are a part of the ordinary common law development of Section 101;²⁴ an important tool for combating unmeritorious litigation²⁵ or preventing overbroad or otherwise harmful patents;²⁶ or beneficial to American consumers by lowering prices.²⁷ In response to stakeholder concerns, there have been a number of administrative and legislative developments that seek to clarify or reform the law of Section 101. In 2019, the U.S. Patent and Trademark Office (USPTO) issued Revised Patent Subject Matter Eligibility Guidance designed to assist USPTO patent examiners in determining patent eligibility with greater clarity and predictability.²⁸ In the 116th Congress, the Senate Judiciary Committee's Intellectual Property Subcommittee held a series of hearings on Section 101 reform, seeking input on reform proposals from various patent stakeholders.²⁹ These efforts led to the introduction of the Patent Eligibility Restoration Act in the 117th and 118th Congresses.³⁰ Separately, the Restoring America's Leadership in Innovation Act has been introduced in recent Congresses and would have reformed Section 101 (along with several other changes to patent law).³¹

This report provides the necessary background and context to understand the legal and practical effects that these legislative reforms would have if enacted.³² First, the report reviews the basic legal principles of the U.S. patent system. Second, it examines the historical development and current state of patentable subject matter law. Third, it reviews several articulated rationales for Section 101 and potential options for Section 101 reform. Finally, it examines recent judicial, administrative, and legislative developments concerning patent-eligible subject matter, including the proposed legislative reforms to Section 101.

This report focuses on patent-eligible subject matter reform from a legal perspective. For an analysis of these issues as they relate to innovation policy, see CRS Report R47267, Patents and Innovation Policy, by Emily G. Blevins (2022).

Patent Law Background

Congress's authority to grant patents derives from the Intellectual Property (IP) Clause of the U.S. Constitution, which grants Congress the power "[t]o promote the Progress of Science and useful Arts, by securing for limited Times to . . . Inventors the exclusive Right to their . . . Discoveries."³³ Patents are generally available to any person who "invents or discovers any new and useful process, machine, manufacture, or composition of matter, or any new and useful improvement thereof."³⁴

Patent rights do not arise automatically. Rather, to obtain patent protection under the Patent Act,³⁵ an inventor must formally apply for a patent with the USPTO, beginning a process called patent prosecution.³⁶ During prosecution, a USPTO patent examiner evaluates the patent application to ensure that it meets all the applicable legal requirements to merit the grant of a patent.³⁷ To be patentable, an invention must be (1) directed at patent-eligible subject matter, (2) useful, (3) new, (4) nonobvious, and (5) adequately disclosed and claimed in the patent application.³⁸ If the USPTO finds these requirements met, it will issue (i.e., grant) the patent.³⁹ Patents typically expire 20 years after the initial patent application.⁴⁰

The current law of patent-eligible subject matter will be discussed separately in detail below.⁴¹ The remainder of this section briefly reviews the other requirements for patentability, the scope and effect of patent claims, and the legal rights granted to the holder of a valid patent.

Requirements for Patentability Section 101: Utility

Along with its subject matter requirements, Section 101 contains a requirement that a patented invention must be "useful."⁴² In particular, courts have held that an invention must have both a specific and substantial utility to be patentable.⁴³ The utility requirement derives from the Constitution's command that patent laws exist to "promote the Progress of . . . useful Arts."⁴⁴ The constitutional purpose of patent law thus requires a "benefit derived by the public from an invention with substantial utility," where the "specific benefit exists in currently available form."⁴⁵ This standard for utility is low, however, requiring only that the claimed invention have some "significant and presently available benefit to the public" that "is not so vague as to be meaningless."⁴⁶

Section 102: Novelty

Perhaps the most fundamental requirement for patentability is that the claimed invention must be new. The USPTO will not issue a patent if "the claimed invention was patented, described in a printed publication, or in public use, on sale, or otherwise available to the public before the effective filing date of the claimed invention."⁴⁷ In other words, if every element of the claimed invention is already disclosed in the "prior art"—the information available to the public at the time of the patent application—then the alleged inventor "has added nothing to the total stock of knowledge," and no valid patent may issue to her.⁴⁸

Section 103: Nonobviousness Even if a claimed invention is novel in the narrow sense that it is not "identically disclosed" in a prior-art reference (such as an earlier patent or publication), the invention must further be nonobvious to be patentable.⁴⁹ Specifically, an invention cannot be patented if "the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious . . . to a person having ordinary skill" in the relevant technology.⁵⁰ When determining obviousness, courts also evaluate secondary considerations (also known as "objective indicia") of nonobviousness such as "commercial success, long felt but unsolved needs, [or] failure of others . . . to give light to the circumstances surrounding the origin of the subject matter sought to be patented."⁵¹ By its nature, obviousness is an "expansive and flexible" inquiry that cannot be reduced to narrow, rigid tests.⁵² Nonetheless, if an invention merely combines "familiar elements according to known methods," yielding only "predictable results," it is likely to be obvious.⁵³ Section 112(a): Written Description, Enablement, Best Mode

Finally, the Patent Act imposes several requirements relating to the technical disclosures in the patent application. These provisions are intended to ensure that the patent adequately describes the invention such that the public can use the invention after the expiration of the patent term.⁵⁴ Section 112(a) of the Patent Act requires that patents must contain a "specification" that includes

a written description of the invention, and of the manner and process of making and using it, in such full, clear, concise, and exact terms as to enable any person skilled in the art to . . . make and use the same, and shall set forth the best mode contemplated by the inventor or joint inventor of carrying out the invention.⁵⁵

This statutory language yields three basic disclosure requirements for patentability.⁵⁶ First, to satisfy the written description requirement, the specification must "reasonably convey[] to those skilled in the art that the inventor had possession of the claimed subject matter as of the filing date" of the patent application.⁵⁷ Second, to satisfy the enablement requirement, the specification must contain enough information to teach a person skilled in the art how "to make and use the invention without undue experimentation."⁵⁸ Finally, to satisfy the best mode requirement, if the inventor knew of a preferred way of practicing her invention at the time of the patent application, the specification must disclose that "preferred embodiment[]" of the invention.⁵⁹

Patent Claims Section 112(b): Definiteness If granted, the legal scope of the patent is defined by the patent claims, a sequence of statements that formally set forth the patentee's asserted rights. In essence, while the specification explains the invention in a technical sense, the claims set forth the legal effect of the patent.⁶⁰ Much as a deed may describe the boundaries of a tract of land, the claims define the "metes and bounds" of the patent right.⁶¹ Patent claims must be sufficiently definite to be valid—that is, they must "particularly point[] out and distinctly claim[] the subject matter which the inventor . . . regards as the invention."⁶² In other words, when the claims are read in context, they must "inform, with reasonable certainty, those skilled in the art about the scope of the invention."⁶³ Section 112(f): Functional Claiming For the most part, the current Patent Act uses a system of peripheral claiming, in which the patent claims formally set out the outer boundaries of the patentee's rights.⁶⁴ However, the Patent Act still retains elements of its former system of central claiming, in which the patentee would describe the core principles or examples of what he had invented, but need not formally delineate the outer boundaries of his rights.⁶⁵ For example, under the doctrine of equivalents, an accused infringer may be found liable even if his product does not literally meet every element of the patent claims, if the differences between a claim element and its alleged equivalent in the accused product are "insubstantial."⁶⁶

A potential danger of a peripheral claiming system is that patentees may seek to claim more than they invented by couching the patent claims in broad, functional language—that is, by claiming a result or goal without limitation to any specific structure or device that accomplishes the result.⁶⁷ In Halliburton Oil Well Cementing Co. v. Walker, the Supreme Court limited this practice, invalidating as indefinite a "functional" patent claim, in which the invention—an apparatus for determining the location of an obstruction in an oil well—was claimed not in terms of specific machinery, but instead as a "means for" performing various functions.⁶⁸

Functional claims (also known as "means-plus-function" claims) such as those in Halliburton may be convenient for the patentee, who can express a claim element in terms of a general end, rather than an "exhaustive list" of every possible apparatus that could be used to perform that goal.⁶⁹ On the other hand, as Halliburton recognized, functional claims may be overbroad and ambiguous, or permit the patentee to claim more than he actually invented.⁷⁰ In the Patent Act of 1952, Congress enacted current Section 112(f) as a compromise for functional claims, overruling Halliburton⁷¹ but providing a standard to make functional claims more definite.⁷²

Under Section 112(f), a patentee may opt to express a claim element as "a means or step for performing a specified function without the recital of structure, material, or acts in support thereof."⁷³ If the patentee chooses to claim functionally, however, the claim is construed not to cover all possible means of performing the function, but only "the corresponding structure, material, or acts described in the specification and equivalents thereof."⁷⁴ Courts have held that a patentee is presumed to invoke Section 112(f) when the term "means" is used in the claims.⁷⁵ Conversely, there is a presumption that the patentee does not invoke Section 112(f) if she does not use the term "means," but that presumption may be overcome, such that Section 112(f) will apply to any claim that fails to recite a "sufficiently definite structure" for performing a function.⁷⁶

Rights of Patent Holders

With some exceptions, a patent is generally granted "for a term beginning on the date on which the patent issues and ending 20 years from the date on which the application for the patent was filed."⁷⁷ The Patent Act includes provisions that may modify the 20-year term, including to account for excessive delays in patent examination at the USPTO,⁷⁸ or delays associated with obtaining marketing approval from other federal agencies.⁷⁹

Once granted, a valid patent gives the patent holder the exclusive right to make, use, offer to sell, sell, or import the invention in the United States until the patent expires.⁸⁰ Any other person who practices the invention (i.e., makes, uses, offers to sell, sells, or imports it) without permission from the patent holder infringes the patent and may be liable for monetary damages and injunctive relief if sued by the patentee.⁸¹ To obtain relief from infringement, the patentee must generally sue in court.⁸² Patent law is an area of exclusive federal jurisdiction,⁸³ and the traditional forum for most patent disputes is federal district court.⁸⁴ Although patent suits may be filed in any district court across the country with jurisdiction over the defendant and proper venue,⁸⁵ a single specialized court, the U.S. Court of Appeals for the Federal Circuit (Federal Circuit), hears all appeals in patent cases.⁸⁶ Defending Against Patent Suits

Parties accused of patent infringement may defend on several grounds. First, the accused infringer may claim an "absence of liability" because of noninfringement.⁸⁷ In other words, even presuming the patent is valid, the patentee may fail to prove that the activities of the accused infringer fall within the scope of the patent claims—that is, the accused infringer is not making, using, selling, or importing the patented invention.⁸⁸ Second, although patents benefit from a presumption of validity, the accused infringer may assert that the patent is invalid.⁸⁹ To prove invalidity, the accused infringer must show, by clear and convincing evidence, that the USPTO should not have granted the patent because it failed to meet the requirements for patentability.⁹⁰ Thus, for example, the accused infringer may argue that the invention lacks novelty, is obvious, or claims nonpatentable subject matter; that the patent fails to enable the invention; or that the patent claims are indefinite.⁹¹ Finally, the accused infringer may assert as a defense that the patent is unenforceable based on the inequitable or illegal activities of the patent holder, such as obtaining the patent through fraud on the USPTO.⁹² While the patent holders bears the burden of proving infringement,⁹³ the accused infringer bears the burden of proving invalidity or inequitable conduct.⁹⁴

Following the passage of the 2011 Leahy-Smith America Invents Act (AIA),⁹⁵ the Patent Trial and Appeal Board (PTAB) has become an increasingly important forum for patent disputes.⁹⁶ The AIA created several new administrative procedures for challenging patent validity, including (1) post-grant review (PGR), which allows any person to challenge patent validity based on any of the requirements of patentability if the PGR petition is filed within nine months of the patent's issuance;⁹⁷ (2) inter partes review (IPR), which allows any person other than the patentee to challenge patent validity on limited grounds (novelty or obviousness based on prior patents or printed publications) at any time more than nine months following the patent's issuance;⁹⁸ and (3) a transitional program for covered business method patents (CBM), a PGR-like process limited to certain patents claiming "business methods" that was available only through September 2020.⁹⁹ Of these procedures, IPR is by far the most widely used.¹⁰⁰ IPRs can only be used to seek cancellation of patents based on a lack of novelty or nonobviousness, and not on Section 101 grounds (i.e., claiming ineligible subject matter).¹⁰¹ The Law of Section 101

At a general level, there are two basic requirements for an invention to claim patent-eligible subject matter. First, the invention must fit into one or more of the four statutory categories in Section 101—the claimed invention must be a (1) process, (2) machine, (3) manufacture, or (4) composition of matter.¹⁰² Given the (intentionally) expansive nature of these terms, nearly all claimed inventions will satisfy this requirement.¹⁰³ Still, exceptions to this rule do exist. For example, in In re Nuijten, the Federal Circuit held that a transitory electromagnetic signal was neither a process, machine, manufacture, or composition of matter, and was therefore not patent-eligible subject matter.¹⁰⁴

Because most claimed inventions fit into one of the four statutory categories, the second requirement tends to be more practically important, and receives more attention.¹⁰⁵ The second patentable subject matter requirement is that the invention cannot claim one of the judicially created categories of ineligible subject matter. That is, the claimed invention must not be a (1) law of nature, (2) natural phenomenon, or (3) abstract idea.¹⁰⁶ As explained below, the modern Supreme Court has articulated a two-step test for this second requirement, known as the Alice/Mayo framework.¹⁰⁷ The Supreme Court has justified the three ineligible categories as necessary to prevent patent monopolies on the "'basic tools of scientific and technological work,'" which "might tend to impede innovation more than it would tend to promote it."¹⁰⁸ Thus, the Court has explained that "a new mineral discovered in the earth or a new plant found in the wild is not patentable subject matter. Likewise, Einstein could not patent his celebrated law that E=mc²; nor could Newton have patented the law of gravity."¹⁰⁹ At the same time, the Court has said that even if a mathematical formula or law of nature is not patentable "in the abstract," a practical application of such a principle or law "to a new and useful end" is patent-eligible.¹¹⁰ Beyond such broad illustrations, it is not easy to define what an "abstract idea," "law of nature," or "natural phenomenon" is.¹¹¹ Because these exceptions to patent-eligible subject matter are judicially created, they have no formal statutory definition; their meaning has instead been developed through two centuries of case-by-case "common law" adjudication in the federal courts.¹¹² As a result, the scope of patentable subject matter has waxed and waned over time, depending on the trends in judicial decisions.¹¹³

This section overviews the leading Supreme Court cases addressing patent-eligible subject matter, beginning with formative cases from the 19th century and culminating in the series of 2010s Supreme Court decisions that have led some to call for legislative reform of Section 101.¹¹⁴

Historical Development of the Judicial Exceptions to Patent-Eligible Subject Matter Nineteenth Century The 1853 case of Le Roy v. Tatham, the "fountainhead" of American patentable subject matter jurisprudence,¹¹⁵ concerned a patent on machinery to manufacture metal pipes that exploited a newly developed property of lead.¹¹⁶ Although the Court ultimately did not decide the case on subject matter grounds,¹¹⁷ Le Roy relied on influential English patent cases¹¹⁸ to set forth a basic distinction between abstract "principles" and natural laws (which may not be patented) and practical applications of those principles (which may be patented).¹¹⁹ The Court stated that "[a] principle, in the abstract, is a fundamental truth; an original cause; a motive; these cannot be patented, as no one can claim in either of them an exclusive right."¹²⁰ On the other hand, a "new property discovered in matter, when practically applied, in the construction of a useful article of commerce or manufacture, is patentable," for the "invention is not in discovering [the natural principles], but in applying them to useful objects."¹²¹

In its next term, the Court applied this rule to Samuel Morse's patent on the telegraph in the famous case O'Reilly v. Morse.¹²² Although the Court found that Morse was the first inventor of the telegraph and sustained much of his patent,¹²³ the Court rejected Morse's eighth claim to any "use of the motive power of the electric or galvanic current . . . however developed for marking or printing intelligible characters, signs, or letters, at any distances, being a new application of that power of which I claim to be the first inventor or discoverer."¹²⁴ Observing that "the discovery of a principle in natural philosophy or physical science, is not patentable,"¹²⁵ Chief Justice Roger Taney's majority opinion held that Morse's eighth claim was "too broad" because he had not discovered "that the electric or galvanic current will always print at a distance, no matter what may be the form of the machinery" used, but only that the specific machinery disclosed in the patent specification would do so.¹²⁶

In the second half of the 19th century, the Court issued a series of important decisions on the patentability of processes. The result of these cases was a move away from an earlier rule that prohibited "pure" method patents as ineligible (i.e., a process claimed independently of the specific machinery used to accomplish the method) either by construing nominal process patents as claiming a machine or limiting the process patents to the machinery disclosed and its equivalents.¹²⁷ In Cochrane v. Deener, which involved a patent on an improved manufacturing process for flour, the Court defined a patentable process as "a mode of treatment of certain materials to produce a given result. It is an act, or a series of acts, performed upon the subject-matter to be transformed and reduced to a different state or thing."¹²⁸ Cochrane held that such methods are patentable "irrespective of the particular form of the instrumentalities used."¹²⁹ Similarly, in Tilghman v. Proctor, the Court held that a method for separating fat into glycerin and fatty acids using water, pressure, and heat was patentable.¹³⁰

In The Telephone Cases, the Court distinguished Morse to allow Alexander Graham Bell's patent claim on a "method of and apparatus for transmitting vocal or other sounds telegraphically, as herein described, by causing electrical undulations, similar in form to the vibrations of the air accompanying the said vocal or other sounds, substantially as set forth."¹³¹ Chief Justice Edward Douglass White interpreted Morse as holding that "the use of magnetism as a motive power, without regard to the particular process with which it was connected in the patent, could not be claimed, but that its use in that connection could."¹³² The Court found that Bell's claim, unlike Morse's, did not reach uses of electricity to transmit speech that are "distinct from the particular process with which it is connected in [Bell's] patent," and upheld the claim, so construed.¹³³

Twentieth Century

In the first half of the 20th century, the Court decided two major cases on the patentability of natural phenomena. In American Fruit Growers v. Brogdex Co., the Court rejected patent claims on citrus fruit treated with a solution of borax to render it resistant to mold.¹³⁴ The Court held that treated fruit was not a "manufacture" under Section 101, but a patent-ineligible "natural article"; treatment with borax did not effect a "change in the name, appearance, or general character of the fruit" or imbue it with a "new or distinctive form, quality, or property."¹³⁵ In Funk Brothers Seed Co. v. Kalo Inoculant Co., the Court rejected patent claims on an inoculant for leguminous plants consisting of multiple species of bacteria, where the particular bacterial strains were selected to avoid inhibiting each other (as prior multispecies combinations had).¹³⁶ Because the patentee's combination "produces no new bacteria [and] no change in the six species of bacteria," Justice William Douglas's majority opinion held that it was only "the discovery of some of the handiwork of nature and hence is not patentable."¹³⁷

From 1972 to 1981, the Supreme Court decided four patentable subject matter cases.¹³⁸ In Gottschalk v. Benson, the Court held that an algorithm for converting binary-coded decimal numerals into pure binary numerals (either by hand, or, more practically, on a computer) was patent-ineligible.¹³⁹ Justice Douglas reasoned that "one may not patent an idea" and that upholding this patent would "wholly pre-empt the mathematical formula and in practical effect would be a patent on the algorithm itself."¹⁴⁰ Second, in Parker v. Flook, the Court rejected a patent on a method for updating alarm limits during catalytic conversion of hydrocarbons (such as petroleum), which relied in part on a mathematical formula, because the only novel feature of the method was the mathematical formula.¹⁴¹ Third, in Diamond v. Chakrabarty, the Court upheld a patent on a genetically engineered bacterium useful in breaking down oil (e.g., in cleaning up oil spills).¹⁴² Chief Justice Warren Burger distinguished American Fruit Growers and Funk Brothers because this bacterium, although a living organism, was human-made and possessed "markedly different characteristics from any [bacteria] found in nature."¹⁴³ Finally, in Diamond v. Diehr, the Court distinguished Flook to uphold a patent on a process for molding synthetic rubber that relied on a mathematical formula (the Arrhenius equation).¹⁴⁴ Justice William Rehnquist's majority opinion reached back to Cochrane v. Deener, holding that the process at issue was patentable because it transformed an article (uncured rubber) into a different state or thing.¹⁴⁵ Even though the method used a mathematical formula, the patent in Diehr did not claim the formula itself and would not "pre-empt the use of that equation" in other fields.¹⁴⁶

After Diehr, the Court did not decide a major patentable subject matter case for nearly 30 years.¹⁴⁷ Development of patent-eligible subject matter law was mainly left to the Federal Circuit, whose decisions generally expanded patent-eligible subject matter,¹⁴⁸ such that by the late 1990s Section 101 became perceived as "a dead letter."¹⁴⁹

The Modern Alice/Mayo Framework

In 2010, the Supreme Court reentered the field of patent-eligible subject matter, deciding four cases on the issue within five years.¹⁵⁰ These cases established the two-step Alice/Mayo test for patentable subject matter.

The first step of the Alice/Mayo test addresses whether the patent claims are "directed to" an ineligible concept: a law of nature, a natural phenomenon, or an abstract idea.¹⁵¹ The inquiry at step one focuses on the "claim as whole."¹⁵² To be "directed to" an eligible concept at step one of Alice/Mayo, the claims must not simply involve a patent-ineligible concept.¹⁵³ Rather, the "focus of the claims" must be a patent-ineligible concept, and not the improvement of a technological process.¹⁵⁴ If the patent claims are not directed to an ineligible concept, then the subject matter is patent-eligible.¹⁵⁵

If the claims are directed to an ineligible category, then the invention is not patentable unless the patent claims have an "inventive concept" under the second step of the Alice/Mayo test.¹⁵⁶ Step two of Alice/Mayo considers the elements of each patent claim both individually and as an ordered combination in the search for an "inventive concept"—additional elements that "transform the nature of the claim" into a patent-eligible application of an ineligible concept.¹⁵⁷ To have an "inventive concept," the patent claims must contain elements "sufficient to ensure that the patent in practice amounts to significantly more than a patent upon the [ineligible concept] itself."¹⁵⁸ Claim limitations that are "conventional, routine and well understood," such as generic computer implementation, cannot supply an inventive concept.¹⁵⁹

Bilski v. Kappos, the first in the series of Supreme Court cases that developed what became known as the Alice/Mayo framework, concerned a patent on a business method for hedging against price-fluctuation risks in energy and commodity markets.¹⁶⁰ The Federal Circuit had held that this method was not patentable as a "process" under Section 101 because it failed the "machine-or-transformation test"—that is, it was neither "tied to a particular machine or apparatus" nor "transform[ed] a particular article into a different state or thing."¹⁶¹ All nine members of the Supreme Court agreed with that result—that the business method at issue was not patent-eligible—but differed significantly as to their reasoning. Writing for five Justices, Justice Anthony Kennedy held that the machine-or-transformation test was not the "sole test" for determining whether a process is patent-eligible but still "a useful and important clue."¹⁶² While the majority rejected the "atextual" notion that business methods were categorically unpatentable under Section 101,¹⁶³ it relied on Benson and Flook to conclude that this particular patent attempted to claim an unpatentable abstract idea: the "concept of hedging risk."¹⁶⁴ Concurring only in the judgment, Justice John Paul Stevens wrote for four Justices who would have held, based on the history of the Patent Act and its constitutional purpose, that business methods were always patent-ineligible.¹⁶⁵

In Mayo Collaborative Services v. Prometheus Laboratories, the Court addressed the scope of the "law of nature" exception.¹⁶⁶ The patent in Mayo claimed a method for measuring metabolites in human blood in order to calibrate the dosage of thiopurine drugs in the treatment of autoimmune disorders.¹⁶⁷ Writing for a unanimous Court, Justice Stephen Breyer's opinion held that the patent claims were addressed to a law of nature: "namely, relationships between concentrations of certain metabolites in the blood and the likelihood that a dosage of a thiopurine drug will prove ineffective or cause harm."¹⁶⁸ Because the claims were little "more than an instruction to doctors to apply the applicable laws when treating their patients," the patent lacked any inventive concept and was held to be patent-ineligible.¹⁶⁹

The next case, Association for Molecular Pathology v. Myriad Genetics, Inc., concerned the applicability of the "natural phenomena" exception to the patentability of human DNA.¹⁷⁰ The inventor in Myriad had discovered the precise location and genetic sequence of two human genes associated with an increased risk of breast cancer.¹⁷¹ Based on this discovery, the patentee claimed two molecules associated with the genes: (1) an isolated DNA segment and (2) a complementary DNA (cDNA) segment, in which the nucleotide sequences that do not code for amino acids were removed in the laboratory.¹⁷² Justice Clarence Thomas's unanimous opinion in Myriad held that isolated DNA segments were nonpatentable products of nature because the patent claimed naturally occurring genetic information.¹⁷³ The Court held, however, that cDNA, as a synthetic molecule distinct from naturally occurring DNA, was patentable even though the underlying nucleotide sequence was dictated by nature.¹⁷⁴

Most recently, Alice Corp. v. CLS Bank International examined the scope of the "abstract idea" category of nonpatentable subject matter.¹⁷⁵ Alice concerned a patent on a system for mitigating "settlement risk"—the risk that only one party to a financial transaction will pay what it owes—using a computer as an intermediary.¹⁷⁶ The Court first held, relying on Bilski, that the invention was directed at "the abstract idea of intermediated settlement."¹⁷⁷ Although this idea was implemented on a computer (which is, of course, a physical machine), the patent lacked an inventive concept because the claims merely "implement[ed] the abstract idea of intermediated settlement on a generic computer."¹⁷⁸

Table 1 summarizes the facts and holding of the Supreme Court's major patentable subject matter cases, in reverse chronological order. Table 1. Major Supreme Court Decisions on Patentable Subject Matter

Case Citation

Claimed Inventions

Holding and Rationale

Alice Corp. Pty. v. CLS Bank Int'l, 573 U.S. 208 (2014)

Computer-implemented method and system for mitigating settlement risk in financial transactions using a third-party intermediary

Ineligible: The claims are drawn to the abstract idea of intermediated settlement; implementation on a generic computer does not transform an ineligible abstract idea into a patent-eligible invention.

Ass'n for Molecular Pathology v. Myriad Genetics, Inc., 569 U.S. 576 (2013)

Isolated human DNA segments and exon-only complementary DNA (cDNA) segments corresponding to genes discovered to be linked to an increased risk of breast cancer

Certain Claims Ineligible: Isolated human DNA segments are patent-ineligible because the nucleotide sequence is a product of nature and isolation from the rest of the genome is insufficient to render them patentable; however, cDNA is patentable because it is not naturally occurring.

Mayo Collaborative Servs. v. Prometheus Labs., Inc., 566 U.S. 66 (2012)

Method for optimizing dosage of thiopurine drugs for treating autoimmune disease, by administering the drug, measuring a metabolite, and adjusting the dosage based on the measurement

Ineligible: The relationship between the concentration of particular metabolites in the blood and a drug's effectiveness is directed to a law of nature, and the claims lack an inventive concept beyond conventional post-solution activity.

Bilski v. Kappos, 561 U.S. 593 (2010)

Business method for hedging against price-fluctuation risks in energy and commodity markets

Ineligible: Although business methods are not categorically patent-ineligible, the process at issue was not patentable because it claimed the abstract idea of hedging risk.

J.E.M. Ag. Supply v. Pioneer Hi-Bred Int'l, Inc., 534 U.S. 124 (2001)

Human-developed inbred and hybrid corn plant varieties and seeds

Eligible: Newly developed plant varieties are human-made manufactures or compositions of matter, even though protection may also be available under the Plant Patent Act or the Plant Variety Protection Act.

Diamond v. Diehr, 450 U.S. 175 (1981)

Process for molding raw, uncured synthetic rubber into cured products, relying on the Arrhenius equation and a programmed computer to calculate the curing time

Eligible: The invention does not claim a mathematical formula or a law of nature as such, but applies a natural law to a particular industrial process that transforms an article into a different state or thing.

Diamond v. Chakrabarty, 447 U.S. 303 (1980)

Genetically engineered bacterium capable of breaking down components in crude oil

Eligible: The genetically engineered bacterium was not naturally occurring and possessed markedly different characteristics from any bacteria found in nature.

Parker v. Flook, 437 U.S. 584 (1978)

Method of updating alarm limits used in catalytic conversion of hydrocarbons (e.g., in oil refining) relying on a mathematical formula

Ineligible: The only novel feature of the invention was a mathematical formula, conventionally applied to a specific field.

Gottschalk v. Benson, 409 U.S. 63 (1972)

Method for converting binary-coded decimal numerals into pure binary numerals on digital computer

Ineligible: The patent claims cover all practical uses of a mathematical algorithm and would, in effect, amount to a patent on the algorithm itself.

Funk Bros. Seed Co. v. Kalo Inoculant Co., 333 U.S. 127 (1948)

Inoculant for leguminous plants comprising several strains of mutually noninhibitive species of bacteria to improve nitrogen fixation

Ineligible: Each bacterial strain is naturally occurring, and discovery of the noninhibitive qualities of certain strains was not invention but merely the discovery of a nonpatentable natural phenomenon.

Mackay Radio & Tel. Co. v. Radio Corp. of Am., 306 U.S. 86 (1939)¹⁷⁹

Radio antenna in which the angle of the wires and their length are determined by a mathematical formula

Assumed to be patentable: Although a mathematical expression of a scientific truth is not patentable, a novel and useful structure created with the aid of knowledge of scientific truth may be patentable.

Am. Fruit Growers v. Brogdex Co., 283 U.S. 1 (1931)

Citrus fruit treated with borax solution to render it resistant to mold

Ineligible: Treatment with borax did not transform the fruit (a product of nature) into a manufacture with a new or distinctive form, quality, or property.

The Telephone Cases, 126 U.S. 1 (1888)

Method and apparatus for transmitting sound telegraphically by causing electrical undulations, similar to air vibrations accompanying speech and other sounds

Eligible: The patentee did not claim all uses of electricity to transmit speech at a distance, but only the particular process and apparatus disclosed in the patent.

Tilghman v. Proctor, 102 U.S. 707 (1881)

Process for separating fat into glycerin and fatty acids using water, pressure, and heat

Eligible: New and useful manufacturing processes are "arts" that may be patented independently of the apparatus used.

Cochrane v. Deener, 94 U.S. 780 (1877)

Improved industrial process for manufacturing flour

Eligible: A process ("a series of acts, performed upon the subject-matter to be transformed and reduced to a different state or thing") is patentable independent of the machinery used.

Rubber-Tip Pencil Co. v. Howard, 87 U.S. (20 Wall.) 498 (1874)

Rubber cap with cavity designed to be attached to lead pencils for convenient use as an eraser

Ineligible: An "idea of itself" (here, the idea of attaching a piece of rubber to the end of a pencil for use as an eraser) is not patentable.

Corning v. Burden, 56 U.S. (15 How.) 252 (1854)

Machine for rolling puddle balls and other masses of iron used in the manufacture of iron products

Eligible: The patentee did not claim the function or abstract effect of a machine, but only the machine that produced the result.

O'Reilly v. Morse, 56 U.S. (15 How.) 62 (1854)¹⁸⁰

Any use of electro-magnetism for printing intelligible characters, signs, or letters, at a distance

Ineligible: The discovery of a scientific principle is not patentable, nor can a patentee claim a useful result in the abstract, apart from the particular process or machine by which the result is accomplished.

Le Roy v. Tatham, 55 U.S. (14 How.) 156 (1853)¹⁸¹

Machinery for manufacturing wrought metal pipes exploiting a newly discovered property of lead

Potentially patentable: Although a principle in the abstract is not patentable, a practical application of such a principle to a new and useful end is patentable.

Source: CRS.

The Debate Over Alice/Mayo and Section 101 Reform A substantial group of patent law stakeholders, including inventors, academics, industry representatives, patent attorneys, current and former Federal Circuit judges, and former USPTO officials, has criticized the Alice/Mayo framework on various grounds.¹⁸² Other patent law stakeholders defend the Supreme Court's Section 101 decisions.¹⁸³ Criticisms of the Alice/Mayo Framework Generally, critics of the Court's patentable subject matter jurisprudence raise four principal concerns. First, the Alice/Mayo framework is criticized as excessively vague, subjective, and unpredictable in application. For example, the Federal Circuit has stated that when determining whether a patent claim is "directed to" an ineligible concept at step one, courts must determine whether the "focus" of the claims is on that concept.¹⁸⁴ At the same time, the Federal Circuit has cautioned that this "focus" must be articulated "with enough specificity to ensure the step one inquiry is meaningful."¹⁸⁵ The appropriate level of specificity can vary from patent to patent and from judge to judge.¹⁸⁶ Thus, in the view of many stakeholders, the Supreme Court's patentable subject matter case law and the Federal Circuit's implementation of the Alice/Mayo framework fail to articulate "objective, predictable criteria" for making patent-eligibility determinations.¹⁸⁷ Key terms, such as what an "abstract idea" is, or precisely how claim elements can make an invention "significantly more" than an ineligible category (the "inventive concept"), are largely left undefined, making it difficult for patent applicants and litigants to know whether their patent claims will survive judicial scrutiny.¹⁸⁸ Moreover, the Federal Circuit has explicitly recognized that the two steps of the analysis are not clearly defined and may overlap.¹⁸⁹ As a result, many observers characterize the court's Section 101 jurisprudence as a "highly subjective," "I know it when I see it" approach.¹⁹⁰ This subjectivity, in the view of critics, injects unpredictability and uncertainty into whether an invention is of a type that is patentable.¹⁹¹

Second, the Alice/Mayo framework is criticized as legally flawed on various grounds. Some stakeholders argue that the Alice/Mayo framework misinterprets Section 101, imposing "extra-statutory" requirements for patent eligibility, contrary to congressional intent or the constitutional purpose of patent law.¹⁹² Others argue that Mayo's requirement of an "inventive concept" rests on a historically inaccurate understanding of 19th century English patent law, first imported into American jurisprudence in cases such as Le Roy and Morse.¹⁹³ Finally, many commentators and stakeholders argue that the Alice/Mayo framework confuses patent law by conflating eligibility under Section 101 with policy concerns—such as the obviousness of the invention and claim breadth—that are better addressed by other provisions in the Patent Act, such as Sections 102, 103, and 112.¹⁹⁴ For example, patent claims have been found to lack an inventive concept at Alice/Mayo step two where they implement an abstract idea on conventional computer hardware.¹⁹⁵ Issues about what was "conventional" or "well-understood" at the time of the invention, however, are questions usually reserved for novelty or nonobviousness analysis.¹⁹⁶

Third, the Alice/Mayo framework is alleged to have detrimental effects on incentives to innovate, especially in the biotechnology and computer software industries. Given the patent claims at issue in Alice (a computer-implemented business method), Myriad (an isolated human DNA segment), and Mayo (a drug dose optimization method), most observers agree that these two industries have been the most affected by the Supreme Court's Section 101 rulings.¹⁹⁷ In the biotechnology industry, stakeholders argue that the Alice/Mayo framework has limited their ability to obtain patents on diagnostic methods and kits, personalized medicine, and isolated natural substances.¹⁹⁸ Views in the computer industry are "sharply divided," but at least some stakeholders argue that Alice has devalued their patents and created uncertainty for their business.¹⁹⁹ In both fields, some stakeholders argue that the law of Section 101 is reducing incentives to innovate in these areas and driving investment elsewhere.²⁰⁰

Finally, the uncertainty and unpredictability caused by Alice/Mayo is alleged to put the United States at a disadvantage relative to international competitors. Some stakeholders argue that U.S. competitiveness may be harmed because a lack of patent availability will drive investment in certain industries to other countries where such inventions are more clearly patent-eligible.²⁰¹ Others argue that one effect of Alice/Mayo is a loss of any patent protection for certain inventions, which will enable competitors to "free ride" off of American innovation.²⁰² Defenses of the Alice/Mayo Framework Defenders of the current law of Section 101 respond that these criticisms of Alice/Mayo are overstated, or that the Supreme Court's reinvigoration of Section 101 has important benefits for the patent system. As to the subjective or unpredictable nature of Section 101 doctrine, there is some empirical evidence that the Alice/Mayo framework is not as unpredictable as is sometimes claimed.²⁰³ Some commentators also observe that uncertainty in patentable subject matter law is hardly a new phenomenon,²⁰⁴ and may even be "inevitable."²⁰⁵ A subjective or "amorphous" approach to patentable subject matter, on this view, may have certain benefits, including flexibility and adaptability to new technologies.²⁰⁶ Moreover, even if one views the current state of the law as unacceptably vague, courts may eventually clarify or change Section 101 doctrine in line with the long history of common law development in this area.²⁰⁷ As to the legal correctness of Alice/Mayo, defenders of the framework note that while the judicially created categories are not directly grounded in the text of Section 101, they have been treated as part of the law "as a matter of statutory stare decisis going back 150 years."²⁰⁸ As to Mayo's reliance on 19th century English patent law, some commentators defend the Supreme Court's "inventive application" requirement as a faithful reading of this precedent.²⁰⁹ Finally, although the Alice/Mayo framework may overlap with other patent law doctrines, several commentators and judges of the Federal Circuit argue that Section 101 serves purposes distinct from Sections 102, 103, and 112.²¹⁰ For example, even if the invention in Myriad—an isolated human DNA sequence discovered to be linked to increased breast cancer risk—was novel, nonobvious, and sufficiently disclosed, some commentators would still argue that the invention should not be patented based on harm to future innovation or moral concerns about patenting human DNA.²¹¹

Regarding the alleged detrimental effects of the Court's Section 101 decisions on innovation, some stakeholders point to countervailing benefits either generally or in certain industries. In particular, some stakeholders in industries (such as computer software) affected by litigation by patent assertion entities²¹² argue that Section 101 is a useful and important tool for weeding out overly broad or vague patents at the outset of litigation.²¹³ Other commentators point to general utilitarian or moral benefits of robust exclusions for patents on basic discoveries in science and nature.²¹⁴

Lastly, in response to concerns about the Alice/Mayo framework's effect on international competitiveness, some commentators assert that these changes are good for the United States as a geopolitical matter.²¹⁵ In particular, restricted patent-eligibility standards may benefit U.S. consumers if a lack of patent protection leads to increased competition and lower prices for certain products without harming innovation.²¹⁶ Views on the Purposes of Section 101 There is a long-running debate over the functions and purposes that Section 101 serves in the patent system. For its part, the modern Supreme Court has largely settled on the "preemption rationale" for the judicially created subject matter exclusions. These decisions assert that abstract ideas, laws of nature, and natural phenomena should not be patentable because permitting a monopoly on the "'basic tools of scientific and technological work' . . . might tend to impede innovation more than it would tend to promote it,"²¹⁷ in that such patents would "significantly impede future innovation."²¹⁸ The gist of the preemption rationale is that Section 101 functions to prevent patents that reach so broadly that they "threaten downstream innovation" by preempting all uses of a natural law, abstract idea, or fundamental research tools.²¹⁹ The preemption rationale is not the only potential justification for Section 101, however. Although a complete survey of the various rationales proffered for Section 101 is beyond the scope of this report, at least four broad categories of rationales for Section 101 have been proposed.²²⁰

First, some commentators argue that Section 101's purpose is to identify certain patents or categories of patents that should not be granted because their economic harms exceed their benefits—that is, their net social costs are negative for innovation, or more generally.²²¹ Preemption theory, which claims that certain overbroad patents should be denied patent protection under Section 101 because of their negative effects on downstream innovation, is an example from this group.²²²

Second—in what is in some sense a special case of the first rationale—other commentators assert that Section 101's purpose is to identify and deny patents to categories of inventions that would have been developed even without a patent incentive.²²³ For example, several commentators have argued the patents on business methods should be excluded under Section 101 either because they affirmatively harm innovation and the economy, or because they are simply unnecessary because sufficient incentives to create business methods would exist even if patents are unavailable.²²⁴

Third, some commentators assert that Section 101 (or elements of Section 101 doctrine) are based not on economic considerations but on moral or ethical concerns.²²⁵ For example, the judicial prohibition on patenting products of nature—such as human DNA sequences—may be motivated by noneconomic, deontological notions of human dignity, or the inviolability of natural creation.²²⁶

Finally, some commentators believe that Section 101 serves no independent purpose in patent law not already better served by other patentability requirements.²²⁷ On this view, Section 101's judicially created exceptions to patentable subject matter should simply be eliminated as an independent requirement for patentability, in favor of a rigorous application of the other patentability requirements in Sections 102, 103, and 112 of the Patent Act.²²⁸

Potential Options for Section 101 Reform

Before examining the particular approaches used in USPTO guidance and proposed legislative reforms, this section reviews some of the general ways in which Section 101 may or may not be reformed. These different paths are introduced to contextualize the current Section 101 reform proposals within the universe of possible reforms. This list is not exhaustive, nor are each of these options necessarily mutually exclusive.

At a general level, most of the proposed paths forward for Section 101 fall into one of four categories.²²⁹ First, some oppose any legislative intervention, proposing instead to allow the courts to continue to develop and refine the standards for patent eligibility.²³⁰ Second, some propose replacing the Alice/Mayo framework with an explicit list of subject matter that is patent-eligible or -ineligible, similar to the approach that is used for European patents.²³¹ Third, some propose replacing the Alice/Mayo framework with a different, usually lower, standard for patent eligibility, such as a requirement that the invention result from human effort, exist outside the human mind, or contribute to the technological arts.²³² Fourth, some propose to do away with any limitations on patentable subject matter, beyond the four statutory categories and other existing statutory patentability requirements.²³³ Continued Common Law Judicial Development Congress could leave Section 101 as it is, and allow the courts and the USPTO to continue developing the law of patent-eligible subject matter. Stakeholders and commentators may support this option for several different reasons. Some may disagree that the Alice/Mayo framework is as indeterminate or as harmful to innovation as the critics claim.²³⁴ Other commentators, even if they accept the criticisms directed at Alice/Mayo, believe that the courts will eventually refine, clarify, or otherwise improve the law of patentable subject matter given more time for judicial development.²³⁵ Still other commentators support the current law of Section 101 as affirmatively good for innovation and society because it precludes property rights in fundamental aspects of science, nature, and ideas,²³⁶ or serves as an important mechanism to weed out overly broad patents or obtain early dismissal of unmeritorious patent litigation.²³⁷

Supporters of continued judicial development may point to the administrative guidance put forth by the USPTO²³⁸ and significant Section 101 decisions of the Federal Circuit²³⁹ as promising steps in the development of Section 101 after the Alice, Mayo, and Myriad decisions. Opponents of maintaining the legal status quo, for their part, observe that the Supreme Court has not shown much interest in revisiting its Section 101 jurisprudence despite many opportunities,²⁴⁰ and that the USPTO and the Federal Circuit are bound by the Court's decisions.

Specific Statutory List of Included or Excluded Subject Matter Categories

Another potential option would be for Congress to amend Section 101, replacing the Alice/Mayo framework with a more specific list of subject matter that is patent-eligible or ineligible. Currently, Section 101 contains a broad list of included subject matter categories (processes, machines, manufactures, and compositions of matter), and most of the doctrine focuses on the three judicially created ineligible categories: laws of nature, natural phenomena, and abstract ideas.²⁴¹ The "laundry list" approach would seek to make Section 101 clearer and more predictable by more specifically defining categories of eligible or ineligible subject matter.²⁴² Depending on how this sort of proposal is structured, it would retain the notion of ineligible classes of subject matter, but define such categories differently, more precisely, and perhaps more narrowly than the common law exceptions under the Alice/Mayo framework.

The European Patent Convention's (EPC's) approach to patent eligibility offers a potential model for this type of approach.²⁴³ Under EPC article 52(1), patent-eligible subject matter reaches "all fields of technology, provided that they are new, involve an inventive step and are susceptible of industrial application."²⁴⁴ At the same time, EPC article 52(2) defines specific subject matter that is not patentable when claimed "as such":

(a) discoveries, scientific theories and mathematical methods;

(b) aesthetic creations;

(c) schemes, rules and methods for performing mental acts, playing games or doing business, and programs for computers;

(d) presentations of information.²⁴⁵

EPC article 53 further denies patents on inventions that are "contrary to [public order] or morality," claim "plant and animal varieties," or claim "methods for treatment of the human or animal body by surgery or therapy and diagnostic methods practised on the human or animal body."²⁴⁶

Assuming that the new statutory categories are more clearly defined than existing judicial categories, a potential virtue of the laundry-list approach is greater clarity and predictability in the sort of inventions that are patentable.²⁴⁷ This approach would also more firmly ground subject matter determinations in the statutory text. On the other hand, the list-of-specific-exclusions approach might be less flexible and less able to adapt to unforeseen new technologies than other options.²⁴⁸ It might also, to some degree, replace case-by-case judicial judgments of eligibility with more categorical legislative ones, which may be a virtue or a vice depending on one's perspective.²⁴⁹

Replace Judicial Exceptions with a Different Standard

A third group of proposed Section 101 reforms seeks to replace the Alice/Mayo framework with a new statutory standard for assessing patent eligibility.²⁵⁰ Proposals in this category are fairly diverse, but common elements in proposed new standards would limit patent eligibility to inventions that

• result from human effort;²⁵¹
• contribute to the technological arts;²⁵²
• have practical utility or application;²⁵³
• cannot be solely performed in the human mind;²⁵⁴
• do not preempt all practical uses of a law of nature, abstract idea, or natural phenomenon.²⁵⁵

Usually, the proposed new patentability standard would supersede the three judicially created subject matter exclusions and the two-step Alice/Mayo test.²⁵⁶

Several proposed new standards blend more than one of these elements. For example, the American Intellectual Property Law Association has submitted a Section 101 reform proposal that replaces the Alice/Mayo framework with a single exception to patent eligibility if an invention "exists in nature independently of and prior to any human activity" or "is performed solely in the human mind."²⁵⁷ A 2017 proposal by the American Bar Association (ABA) would explicitly allow patenting "practical applications" of laws of nature, natural phenomena, and abstract ideas, so long as the patent claim does not "preempt the use by others of all practical applications of the law of nature, natural phenomenon, or abstract idea."²⁵⁸

It is difficult to generalize given the significant differences among the various proposals in this category, but stakeholders may wish to consider whether proposed new standards would provide greater clarity and predictability in patent-eligibility law, while still being flexible enough to adapt to new technologies.²⁵⁹

Eliminate Implied Patentable Subject Matter Limits

Another option would be for Congress to eliminate the Alice/Mayo framework and judicially created exceptions to patent eligibility altogether, without replacing them with a new standard or statutory exceptions.²⁶⁰ Several commentators have argued that patent-eligibility doctrine serves no purpose that is not already served by the existing statutory patentability requirements of utility, novelty, obviousness, written description, definiteness, and enablement.²⁶¹ On this view, the appropriate course would be for Congress to simply eliminate the nonstatutory eligibility requirements (i.e., the judicial prohibitions on patenting laws of nature, natural phenomena, and abstract ideas) in favor of the application of the patentability requirements of Sections 102, 103, and 112 of the Patent Act.²⁶²

Supporters of this approach argue that it advances the policy concerns motivating Section 101 law, but does so in a "more consistent and more rigorous" manner.²⁶³ Opponents argue that Section 101 serves important purposes that are distinct from the other patentability requirements, which would be lost if the judicial exceptions were eliminated.²⁶⁴

Post-Alice Developments in Patent-Eligible Subject Matter Law and Proposed Reforms The Supreme Court's modern patentable subject matter jurisprudence has led to responses from the courts, the USPTO, and Congress. This section reviews recent judicial, administrative, and legislative developments on patent-eligible subject matter standards and proposed reforms. Judicial Developments

Since its 2014 decision in Alice, the Supreme Court has denied dozens of petitions for certiorari (i.e., requests that the Court hear an appeal) on Section 101 issues, despite calls from some patent law stakeholders asking the Court to revisit its patent-eligible subject matter jurisprudence.²⁶⁵ For example, in Sequenom v. Ariosa Diagnostics, Inc.,²⁶⁶ the Supreme Court denied certiorari despite 22 amicus briefs supporting certiorari and calls from commentators, stakeholders, and Federal Circuit judges urging the Court to take the case to clarify Section 101.²⁶⁷ Similarly, in opinions concerning rehearing en banc in Athena Diagnostics, Inc. v. Mayo Collaborative Services,²⁶⁸ all of the active judges on the Federal Circuit called upon the Supreme Court (or Congress) to change Section 101 law to clearly allow for the patenting of diagnostic methods.²⁶⁹ The Supreme Court nonetheless denied certiorari in Athena and again declined to revisit its Section 101 case law.²⁷⁰

Another prominent Section 101 case that the Court declined to hear was American Axle & Manufacturing v. Neapco Holdings.²⁷¹ That case was thought by some observers to be an ideal vehicle for the Court because the patented technology—a method for manufacturing driveline shafts for automotive vehicles—was tangible and relatively straightforward, yet the lower courts held it ineligible as directed to a law of nature.²⁷² As in Athena, the Federal Circuit was closely divided with respect to rehearing American Axle en banc, dividing 6-6, with 5 judges averring that "[Federal Circuit] rulings on patent eligibility have become so diverse and unpredictable as to have a serious effect on the innovation incentive in all fields of technology."²⁷³ Many stakeholders again supported the petition for certiorari in American Axle, including a brief filed jointly by Senator Tillis, the Hon. Paul R. Michel (a former Chief Judge of the Federal Circuit), and David J. Kappos (a former USPTO Director).²⁷⁴ The Supreme Court invited the views of the Solicitor General, who filed a brief supporting a partial grant of certiorari in American Axle.²⁷⁵ The Supreme Court declined to hear the case in 2022.²⁷⁶

In light of the Supreme Court's apparent reluctance to revisit Section 101, the Federal Circuit has continued to develop the law of Section 101 within the constraint of the Supreme Court's precedents,²⁷⁷ deciding many significant cases applying the Alice/Mayo framework.²⁷⁸ The Supreme Court's inaction on Section 101 post-Alice has also led some stakeholders to call for Congress to intervene on the issue.²⁷⁹

Administrative Developments in the USPTO The 2019 Revised Patent Subject Matter Eligibility Guidance In 2019, the USPTO issued Revised Patent Subject Matter Eligibility Guidance (the 2019 Guidance) to assist USPTO patent examiners in determining subject matter eligibility for patent applications.²⁸⁰ The USPTO noted that the "legal uncertainty" surrounding the Alice/Mayo framework "poses unique challenges" for the agency, which has thousands of patent examiners who must make patent-eligibility determinations on hundreds of thousands of applications each year.²⁸¹ Accordingly, the USPTO issued revised guidance to its patent examiners to provide "more clarity and predictability" in their Section 101 determinations.²⁸²

The USPTO subsequently incorporated the 2019 Guidance into the Manual of Patent Examining Procedure (MPEP), which guides USPTO patent examiners in their review of patent applications.²⁸³ The 2019 Guidance made at least two major changes to how patent examiners evaluate whether a patent application claims patent-ineligible subject matter. First, the Guidance seeks to provide a clearer definition of what constitutes an ineligible "abstract idea."²⁸⁴ Previously, examiners would make that determination by comparing the patent claim at issue to those found to be ineligible "abstract ideas" in previous judicial cases.²⁸⁵ The USPTO found that this approach had become "impractical" because of an expanding volume of sometimes contradictory Section 101 case law.²⁸⁶ The 2019 Guidance "distills" the case law into three categories that examiners will treat as "abstract ideas":

1) Mathematical concepts—mathematical relationships, mathematical formulas or equations, mathematical calculations;

2) Certain methods of organizing human activity – fundamental economic principles or practices (including hedging, insurance, mitigating risk); commercial or legal interactions (including agreements in the form of contracts; legal obligations; advertising, marketing or sales activities or behaviors; business relations); managing personal behavior or relationships or interactions between people (including social activities, teaching, and following rules or instructions); and

3) Mental processes – concepts performed in the human mind (including an observation, evaluation, judgment, opinion).²⁸⁷

Under the Guidance, patent claims that do not recite matter that falls into one of these three groupings should not be treated as an "abstract idea" except in "rare circumstance[s]."²⁸⁸

Second, the 2019 Guidance clarifies when examiners will treat a patent claim as "directed to" an ineligible category (abstract ideas, laws of nature, or natural phenomena) under step one of the Alice/Mayo test.²⁸⁹ In particular, the USPTO will not treat a claim as "directed to" an ineligible concept if "the claim as a whole integrates the recited judicial exception into a practical application of the exception."²⁹⁰ If the claim does integrate a practical application—such as improving the functioning of a computer, effecting a particular treatment for a disease, or implementing the exception into a particular machine or manufacture—then the USPTO will treat the claim as patent-eligible, without having to examine the patent application for an "inventive concept" under step two of the Alice/Mayo framework.²⁹¹

The 2019 Guidance was generally perceived as lowering Section 101 barriers to patentability, especially for computer-related inventions.²⁹² Some commentators praised the Guidance for providing greater clarity to patent examiners, while other stakeholders criticized the Guidance as inconsistent with the Supreme Court's Section 101 decisions.²⁹³

Although the USPTO's 2019 Guidance changes how USPTO examiners review new patent applications, the Guidance is not binding on the courts when patents are challenged in litigation (unlike decisions of appellate courts or statutes). The USPTO lacks general substantive rulemaking authority,²⁹⁴ and the Guidance itself states that it is only a "tool for internal USPTO management" that lacks "the force and effect of law."²⁹⁵ Although the Federal Circuit has issued somewhat contradictory signals on this point,²⁹⁶ courts would only follow the Guidance if they found its reasoning to be persuasive and agreed that it was the "best reading" of Section 101.²⁹⁷

Following the 2019 Guidance, the USPTO has continued efforts to increase clarity and consistency in its Section 101 determinations.²⁹⁸ In 2020, the USPTO Office of the Chief Economist issued a report on patent examination outcomes following Alice.²⁹⁹ That study found that while Section 101 rejections in certain technological fields increased by 31% in the 18 months after Alice, the rejection rate decreased by 35% after issuance of the 2019 Guidance, with less variability in outcomes across examiners.³⁰⁰ In response to a 2021 letter from Senators Tillis and Cotton,³⁰¹ the USPTO launched the Deferred Subject Matter Eligibility Response Pilot Program, which invites selected patent applicants to defer consideration of subject-matter eligibility issues until other patentability issues (such as those under Sections 102, 103, and 112) are resolved.³⁰²

2022 USPTO Report on Stakeholder Views In 2022, at the urging of a group of Senators,³⁰³ the USPTO solicited public comment and published a report for Congress summarizing stakeholder views on current patent-eligible subject matter law.³⁰⁴ While the report found a consensus that patent-eligibility law should be "clear, predictable, and consistently applied," stakeholders differed on whether current Section 101 law achieved that ideal.³⁰⁵ Finding a "continuing divide" on the issue, the USPTO report indicated that defenders of the Alice/Mayo framework (primarily from the computer technology industry) found current law to be sufficiently clear and an important tool for addressing overbroad patents and abusive lawsuits.³⁰⁶ On the other side, critics of the Alice/Mayo framework (especially life-science industries) found the current law to be unpredictable and to have detrimental effects on innovation and investment in the development of new technologies.³⁰⁷ 2024 Artificial Intelligence Eligibility Guidance

Patent applications relating to artificial intelligence (AI) technologies doubled between 2002 and 2018.³⁰⁸ Some stakeholders worry that patents on AI inventions are at risk under the Alice/Mayo framework because they might be characterized as claiming abstract ideas.³⁰⁹ In 2024, USPTO issued updated guidance on patent eligibility focusing on AI-related inventions.³¹⁰

USPTO's 2024 AI Eligibility Guidance supplements its general 2019 Guidance on patent-eligible subject matter. As explained above, under the 2019 Guidance, claims are eligible under Alice/Mayo step one if the claim either (1) does not "recite" a judicial exception, or (2) has additional elements that "integrate" the judicial exception into a practical application of ineligible subject matter.³¹¹ The 2024 AI Eligibility Guidance focuses on this step, giving several examples designed to illustrate when claims on AI inventions recite or "merely involve" abstract ideas, and when claims integrate an abstract idea into a practical application by improving the functioning of a computer or another technology.³¹²

As an example, the 2024 AI Eligibility Guidance explains that a claim on an application-specific integrated circuit for an artificial neural network comprising synaptic circuits, a microprocessor, and an array of organized "neurons" is patent-eligible because it is directed to specific hardware components and thus does not recite an abstract idea.³¹³ By contrast, a general method of using a deep neural network to analyze a speech sample with multiple sources is ineligible because it claims a mathematical process.³¹⁴ However, a specific method of using a deep neural network to separate a mixed speech sample, generate separate waveforms for each speech source, and recombine them into a new mixed sample without unwanted sources is eligible as a practical application of an abstract idea.³¹⁵

While some stakeholders appreciated USPTO's efforts to provide more guidance on how examiners will approach patent eligibility issues for AI-related inventions,³¹⁶ others asserted that the 2024 AI Eligibility Guidance should have done more to clarify the application of the Alice/Mayo framework for such inventions.³¹⁷

Legislative Developments The 116th Congress

The 116th Congress saw one formal proposal to reform Section 101 introduced in the House. In the Senate, the Chairman and Ranking Member of the Subcommittee on Intellectual Property of the U.S. Senate Committee on the Judiciary held a series of hearings on Section 101 issues and circulated several informal draft proposals to amend Section 101. Ultimately, these Members did not introduce formal legislation in the 116th Congress.

The Restoring America's Leadership in Innovation Act of 2020

In the House, Representative Massie introduced H.R. 7366, the Restoring America's Leadership in Innovation Act of 2020 (RALIA 2020).³¹⁸ Alongside provisions designed to reverse many of the changes in patent law enacted through the 2011 America Invents Act,³¹⁹ Section 7 of RALIA 2020 would have responded to the Supreme Court's Section 101 decisions. Expressing the view that the Court's recent Section 101 jurisprudence "has harmed the progress of science and the useful arts," RALIA 2020 would have "effectively abrogate[d]" those decisions (specifically, Alice "and [its] predecessors").³²⁰

To "ensure that life sciences discoveries, computer software, and similar inventions and discoveries are patentable," RALIA 2020 would have replaced the three judicially created exceptions to patent-eligible subject matter with a single narrow statutory exception.³²¹ Under RALIA 2020, any new and useful process, machine, manufacture, or composition of matter would have been patent-eligible unless "the claimed invention as a whole, as understood by a person having ordinary skill in the art, exists in nature independently of and prior to any human activity, or exists solely in the human mind."³²² RALIA 2020 would have thus expanded the types of inventions that are patentable compared to the status quo under Alice/Mayo. RALIA 2020 would have also established that eligibility determinations under Section 101 shall be made "without regard as to the requirements or conditions of sections 102, 103, and 112 of this title, or the claimed invention's inventive concept."³²³ This provision would have sought to separate eligibility questions under Section 101 from issues of novelty, nonobviousness, enablement, and disclosure more specifically addressed in other provisions of the Patent Act.

The First Tillis-Coons Proposal

In April 2019, Senators Tillis and Coons—joined by Representatives Collins (GA), Johnson (GA), and Stivers—released a framework for legislative Section 101 reform (the First Tillis-Coons Proposal).³²⁴ The framework's release followed multiple roundtables with patent law stakeholders on Section 101 and the effect of the Alice/Mayo framework on, for example, innovation in artificial intelligence, medical diagnostics, and personalized medicine.³²⁵ The First Tillis-Coons Proposal would have retained the four current statutory categories of patentable inventions, but removed the requirement that the invention or discovery be "new and useful" from Section 101.³²⁶ Patent eligibility would have instead been determined "by considering each and every element of the claim as a whole and without regard for considerations properly addressed by [Sections] 102, 103 and 112 [of the Patent Act]."³²⁷ In place of the judicially created exceptions to patent eligibility, which the First Tillis-Coons Proposal would have abrogated by statute, the proposal listed five "exclusive" categories of patent-ineligible subject matter: (1) fundamental scientific principles; (2) products that exist solely and exclusively in nature; (3) pure mathematical formulas; (4) economic or commercial principles; and (5) mental activities.³²⁸ Effectively, this would have codified aspects of the judicial exceptions in a narrower form, with the first two ineligible categories roughly corresponding to the "law of nature" and "natural product" judicial exceptions, and the final three to the types of "abstract ideas" identified by the USPTO in its 2019 Guidance.³²⁹ The First Tillis-Coons Proposal thus blended elements of the USPTO's 2019 Guidance with a list of specific ineligible categories, plus new statutory standards for how to apply the list of exceptions to patentable subject matter.³³⁰ The overall effect would be to lower Section 101 barriers to patentability, while still retaining more narrowly defined classes of ineligible subject matter.³³¹ Reactions to the First Tillis-Coons Proposal were mixed.³³² Some commentators argued that the draft proposal was a promising start for much-needed congressional intervention.³³³ Some critics of the Alice/Mayo framework argued that the First Tillis-Coons Proposal did not go far enough, and urged elimination of any ineligible categories of patentable subject matter.³³⁴ On the pro-Alice side of the debate, the Electronic Frontier Foundation, for example, criticized the First Tillis-Coons Proposal as detrimental to innovation because it would eliminate a powerful tool to combat bad patents and patent troll litigation.³³⁵ The Second Tillis-Coons Proposal Following feedback on their first draft framework, the same group of Members released a "draft bill" to reform Section 101 (the Second Tillis-Coons Proposal).³³⁶ The Second Tillis-Coons Proposal was released before a series of three public hearings held in the 116th Congress before the Senate Judiciary Committee's Subcommittee on Intellectual Property, which solicited feedback on the draft legislative language.³³⁷ In these hearings, 45 witnesses testified over three days, with representatives from industry, academia, bar associations, and trade groups; former Federal Circuit Judges and USPTO Directors; and other patent law stakeholders expressing various views on Section 101 reform.³³⁸ As compared to the first proposal, the Second Tillis-Coons Proposal would have made more sweeping changes to Section 101 to expand patent eligibility. Like the First Tillis-Coons Proposal, the draft bill had several provisions that attempted to separate the Section 101 inquiry from other patentability requirements. Specifically, the draft bill would have struck the word "new" from Section 101 and established that patent subject matter eligibility must be determined "considering the claimed invention as a whole" and without regard to "considerations relating to section 102, 103, or 112 of [the Patent Act]."³³⁹ The Second Tillis-Coons Proposal provided that eligibility determinations would not depend on the "manner in which the claimed invention was made; whether individual limitations of a claim are well known, conventional or routine; [or] the state of the art at the time of the invention."³⁴⁰ The draft bill also explicitly provided that Section 101 "shall be construed in favor of eligibility."³⁴¹

Rather than narrow the judicial exceptions to patentability, the Second Tillis-Coons Proposal would have eliminated those exceptions altogether. The draft bill provided that

No implicit or other judicially created exceptions to subject matter eligibility, including "abstract ideas," "laws of nature," or "natural phenomena," shall be used to determine patent eligibility under section 101, and all cases establishing or interpreting those exceptions to eligibility are hereby abrogated.³⁴²

This language would have overturned by statute not only the Alice/Mayo framework, but over two centuries of judicial decisions interpreting the "common law" exceptions to Section 101.³⁴³

The Second Tillis-Coons Proposal would have replaced the judicial exceptions with a new statutory definition of utility that incorporated elements of various prior proposals for a new Section 101 standard.³⁴⁴ To be patent-eligible subject matter under the Second Tillis-Coons Proposal, the invention would need to fit into one of the four statutory categories of eligible subject matter (which remain unchanged) and be "useful."³⁴⁵ To be "useful," an invention or discovery would need to provide "specific and practical utility in any field of technology through human intervention."³⁴⁶

Finally, to combat overbroad patent claims, the Second Tillis-Coons Proposal would have altered the functional claiming rules under Section 112(f), which permits patentees to claim their invention in functional terms as opposed to reciting specific physical structures.³⁴⁷ Consistent with decisions of the Federal Circuit,³⁴⁸ the proposal would have clarified that Section 112(f) applies to any claim element that fails to sufficiently recite a structure for performing a function.³⁴⁹ This change could have arguably made it tougher for a patentee to avoid the limiting effects of Section 112(f), even if the words "means for" are not used in the claim language.³⁵⁰ As with the first proposal, reactions to the Second Tillis-Coons Proposal from patent law stakeholders were mixed.³⁵¹ Critics of the Alice/Mayo framework generally applauded the draft bill as bringing much needed clarity and certainty to the law of patent eligibility,³⁵² particularly for biotechnology innovation.³⁵³ Opponents of the draft bill expressed concern that changes to the Alice/Mayo framework would eliminate an important tool against unmeritorious patent litigation.³⁵⁴ Critics also questioned the necessity and advisability of such a sweeping change to Section 101 law.³⁵⁵ Both supporters and opponents raised concerns about potential ambiguities in the proposed definition of "useful," particularly the terms "human intervention," "practical utility," and "field of technology."³⁵⁶

Stakeholders also debated the specific practical effects of the legislative changes at the hearings, such as the effect of elimination of the judicial exceptions on basic scientific research.³⁵⁷ One concern, raised by the American Civil Liberties Union in opposition to the draft bill, was that the Second Tillis-Coons Proposal, by abrogating the Myriad decision,³⁵⁸ would permit the patenting of human genes.³⁵⁹ Several witnesses denied that the draft bill would lead to that result because of the bill's "human intervention" requirement or other patent law principles.³⁶⁰ For their part, Senators Tillis and Coons made clear that they had "no intention" of overruling the result in Myriad that no one may patent "genes as they exist in the human body."³⁶¹

The 117th Congress

The 117th Congress saw two introduced bills that proposed reforms to Section 101, one in the House and one in the Senate.

The Restoring America's Leadership in Innovation Act of 2021

In the House, Representative Massie introduced H.R. 5874, the Restoring America's Leadership in Innovation Act of 2021 (RALIA 2021). Like RALIA 2020, the eligibility provisions of RALIA 2021 would have abrogated the Alice/Mayo framework and replaced the judicially created exceptions to patent-eligible subject matter with a single exception for inventions that "exist[] in nature independently of and prior to any human activity, or exist[] solely in the human mind."³⁶²

The Patent Eligibility Restoration Act of 2022

In the Senate, Senator Tillis introduced S. 4734, the Patent Eligibility Restoration Act of 2022 (PERA 2022). PERA 2022 would have retained the four statutory categories of eligible subject matter, deleted the word "new" in Section 101, and added a statutory definition of "useful."³⁶³ PERA 2022's utility definition would have required that "the invention or discovery has a specific and practical utility from the perspective of a person of ordinary skill in the art."³⁶⁴ In addition, PERA 2022 would have changed the definition of "process" to clarify that "a use, application, or method of manufacture of a known or naturally-occurring process" is patent-eligible.³⁶⁵ Like RALIA, PERA 2022 would have established that patent eligibility determinations should be made without regard to "any consideration in [35 U.S.C.] section 102, 103, or 112" including "whether a claim element is known, conventional, routine, or naturally occurring."³⁶⁶

As in First Tillis-Coons proposal in the 116th Congress, PERA 2022 contains a closed list of the types of inventions that would not be patent-eligible when claimed "as such," specifically:

(A) A mathematical formula, apart from a useful invention or discovery.

(B) A process that—

(i) is a non-technological economic, financial, business, social, cultural, or artistic process;

(ii) is a mental process performed solely in the human mind; or

(iii) occurs in nature wholly independent of, and prior to, any human activity.

(C) An unmodified human gene, as that gene exists in the human body.

(D) An unmodified natural material, as that material exists in nature.³⁶⁷

In effect, PERA would have abrogated the Alice/Mayo framework, and replaced the three judicially created ineligible categories with this closed statutory list of narrower ineligible categories.³⁶⁸

While both PERA 2022 and RALIA 2022 would have expanded the scope of patent-eligible subject matter, PERA's changes are generally more limited than RALIA's. This is because the list of patent-ineligible categories in PERA 2022 (mathematical formulae, non-technological processes, et al.) was broader than RALIA 2021's single exception to patent eligibility (for wholly mental or naturally occurring inventions). In other words, while both bills would have resulted in more patent-eligible inventions than current law, the increase would have been greater under RALIA 2021. For example, a non-technological business method would have been eligible under RALIA 2021, but ineligible under PERA 2022. The 118th Congress

In the 118th Congress, new versions of RALIA and PERA were introduced. In the House, Representative Massie introduced the Restoring America's Leadership in Innovation Act of 2024 (RALIA 2024), which proposed to amend Section 101 in the same way as the earlier versions of RALIA discussed above.³⁶⁹

In the Senate, Senator Tillis introduced S. 4734, the Patent Eligibility Restoration Act of 2023 (PERA 2023).³⁷⁰ PERA 2023 added a new findings section expressing the view that patent-eligible subject matter law "requires significant modification and clarification" and that the legal status quo is marked by "confusion and a lack of consistency."³⁷¹

Like PERA 2022, PERA 2023 would have added a new definition of utility and provided that Section 101 determinations should be made independently of considerations under Sections 102, 103, and 112 of the Patent Act.³⁷² PERA 2023 would have (like PERA 2022) effectively abrogated the Alice/Mayo framework, providing that "any useful process, machine, manufacture, or composition of matter" is patent-eligible subject only to a closed statutory list of ineligible categories.³⁷³ PERA 2023's patent-ineligible categories also remained mostly the same as the previous version. Specifically, mathematical formulae, purely mental or natural processes, unmodified human genes, and unmodified natural material would have been ineligible under both versions of PERA.³⁷⁴

PERA 2023's provisions on ineligible processes varied from those in PERA 2022. The earlier bill would have prohibited patenting a "non-technological economic, financial, business, social, cultural, or artistic process" unless that process "is embodied in a machine or manufacture," but not if "the machine or manufacture is recited in a patent claim without integrating . . . the steps of the process that the machine or manufacture perform."³⁷⁵ PERA 2023 would have made patent-ineligible any "process that is substantially economic, financial, business, social, cultural, or artistic," even if a step in the process "refers to a machine or manufacture."³⁷⁶ That said, if the process "cannot practically be performed without the use of a machine or manufacture" then it would have been patent-eligible.³⁷⁷

Representative Kiley introduced a bill substantially identical to PERA 2023 in the House as the Patent Eligibility Restoration Act of 2024.³⁷⁸

Conclusion

The Supreme Court's 2010s decisions on patent-eligible subject matter have inspired a robust debate among patent law stakeholders as to whether the Court's jurisprudence in this area advances or harms innovation. Actions by lower federal courts, the USPTO, and Congress have responded to the Supreme Court's decisions in various ways, including proposed statutory reforms introduced in the 116th and subsequent Congresses.

Footnotes

1. See generally Diamond v. Chakrabarty, 447 U.S. 303, 308–09 (1980) (tracing the history of statutory language on Diamond v. Chakrabarty, 447 U.S. 303, 308–09 (1980) (tracing the history of statutory language on
patentable subject matter). This observation—and this report more generally—is limited to traditional utility patents on patentable subject matter). This observation—and this report more generally—is limited to traditional utility patents on
useful inventions and discoveries. useful inventions and discoveries. See 35 U.S.C. §§ 100–135. Congress did not provide patent protection for 35 U.S.C. §§ 100–135. Congress did not provide patent protection for “"original original
and ornamental designs for an article of manufactureand ornamental designs for an article of manufacture”" (design patents), (design patents), id. §§ 171–173, and for §§ 171–173, and for “"distinct and new distinct and new
variet[ies] of plantsvariet[ies] of plants”" (plant patents), (plant patents), id. §§ 161–164, until 1842 and 1930, respectively. §§ 161–164, until 1842 and 1930, respectively. See An Act in addition to an act An Act in addition to an act
to promote the progress of the useful arts, and to repeal all acts and parts of acts heretofore made for that purpose, Pub. to promote the progress of the useful arts, and to repeal all acts and parts of acts heretofore made for that purpose, Pub.
L. No. 27-263, 5 Stat. 543 (1842); An Act to provide for plant patents, Pub. L. No. 71-245, 46 Stat. 376 (1930).L. No. 27-263, 5 Stat. 543 (1842); An Act to provide for plant patents, Pub. L. No. 71-245, 46 Stat. 376 (1930).
2 2. Graham v. John Deere Co. of Kan. City, 383 U.S. 1, 7 (1966) (describing Jefferson as Graham v. John Deere Co. of Kan. City, 383 U.S. 1, 7 (1966) (describing Jefferson as “"the author of the 1793 Patent the author of the 1793 Patent
Act”).
3Act"). 3. An Act to promote the progress of useful Arts; and to repeal the act heretofore made for that purpose, Pub. L. No. 2- An Act to promote the progress of useful Arts; and to repeal the act heretofore made for that purpose, Pub. L. No. 2-
11, § 1, 1 Stat. 318, 319 (1793). The first Patent Act, enacted in 1790, had phrased things slightly differently: 11, § 1, 1 Stat. 318, 319 (1793). The first Patent Act, enacted in 1790, had phrased things slightly differently: “"any any
useful art, manufacture, engine, machine, or device, or any improvement therein.useful art, manufacture, engine, machine, or device, or any improvement therein.”" See An Act to promote the progress An Act to promote the progress
of useful Arts, Pub. L. No. 1-7, § 1, 1 Stat. 109, 110 (1790). The Patent Acts of 1836 and 1870 used nearly identical of useful Arts, Pub. L. No. 1-7, § 1, 1 Stat. 109, 110 (1790). The Patent Acts of 1836 and 1870 used nearly identical
language as the 1793 Patent Act. language as the 1793 Patent Act. See An Act to promote the progress of useful arts, and to repeal all acts and parts of An Act to promote the progress of useful arts, and to repeal all acts and parts of
acts heretofore made for that purpose, Pub. L. No. 24-357, § 6, 5 Stat. 117, 119 (1836); An Act to revise, consolidate, acts heretofore made for that purpose, Pub. L. No. 24-357, § 6, 5 Stat. 117, 119 (1836); An Act to revise, consolidate,
and amend the Statutes relating to Patents and Copyrights, Pub. L. No. 41-230, § 24, 16 Stat. 198, 201 (1870). In 1952, and amend the Statutes relating to Patents and Copyrights, Pub. L. No. 41-230, § 24, 16 Stat. 198, 201 (1870). In 1952,
Congress replaced the term Congress replaced the term “"art,art,”" historically used to mean a process or method, with the more modern term historically used to mean a process or method, with the more modern term “"process,process,”
" while defining while defining “process”"process" to mean to mean “"process, art, or method.process, art, or method.”" Patent Act of 1952, Pub. L. No. 82-593, §§ 100–101, 66 Patent Act of 1952, Pub. L. No. 82-593, §§ 100–101, 66
Stat. 792, 797; Stat. 792, 797; see also 1 1 CHISUM ON PATENTSChisum on Patents, , Overview: Historical Development of Patent Law, § 2 n.4 (2019) (§ 2 n.4 (2019) (“"[As [As
used in the 1793 Patent Act, t]he term used in the 1793 Patent Act, t]he term ‘art’'art' meant process or method. meant process or method.”"); Bilski v. Kappos, 561 U.S. 593, 639 (2010) ); Bilski v. Kappos, 561 U.S. 593, 639 (2010)
(Stevens, J., concurring) ((Stevens, J., concurring) (“"That change [from That change [from ‘art’ to ‘process’'art' to 'process'] was made for clarity and did not alter the scope of a ] was made for clarity and did not alter the scope of a
patentable patentable ‘'process.process.’”'" (citing Diamond v. Diehr, 450 U.S. 175, 184 (1981))); The Telephone Cases, 126 U.S. 1, 532 (citing Diamond v. Diehr, 450 U.S. 175, 184 (1981))); The Telephone Cases, 126 U.S. 1, 532
(1888) ((1888) (“"this art—or, what is the same thing under the patent law, this process . . .this art—or, what is the same thing under the patent law, this process . . .”).
4 35 U.S.C. § 101.
5"). 4.

35 U.S.C. § 101.

5. Chakrabarty, 447 U.S. at 308 (, 447 U.S. at 308 (“"In choosing such expansive terms as In choosing such expansive terms as ‘manufacture’ and ‘'manufacture' and 'composition of matter,composition of matter,’
' modified by the comprehensive modified by the comprehensive ‘'any,any,’' Congress plainly contemplated that the patent laws would be given wide Congress plainly contemplated that the patent laws would be given wide
scope.scope.”).
6"). 6. Id. at 309 (quoting S. Rep. No. 1979, 82d Cong., 2d Sess., 5 (1952); H. R. Rep. No. 1923, 82d Cong., 2d Sess., 6 at 309 (quoting S. Rep. No. 1979, 82d Cong., 2d Sess., 5 (1952); H. R. Rep. No. 1923, 82d Cong., 2d Sess., 6
(1952)).(1952)).
7 7. See 35 U.S.C. §§ 102–103, 112; 35 U.S.C. §§ 102–103, 112; see generally infra "“Requirements for Patentability.”
8." 8. See Patent Technology Centers Management, U.S. , U.S. PAT. & TRADEMARK OFF., Pat. & Trademark Off., https://www.uspto.gov/patent/contact-https://www.uspto.gov/patent/contact-
patents/patent-technology-centers-management (last visited patents/patent-technology-centers-management (last visited Nov. 21, 2022Mar. 6, 2025) (listing technological divisions for ) (listing technological divisions for PTO
USPTO examiners).examiners).
9 Diehr, 450 U.S. at 185.
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exceptions “define[] the reach of the statute as a matter of statutory stare decisis going back 150
years.”10
In a series of decisions in the 2010s, the Supreme Court relied on Section 101 to reject patent
claims on
 a method for hedging price-fluctuation risks in commodity markets;11
 a method for measuring metabolites in human blood to calibrate the dosage of
particular drug;12
 isolated human DNA segments;13 and
 a method of mitigating settlement risk in financial transactions using a
computer.14
These cases established a two-step test for patentable subject matter sometimes called the
“Alice/Mayo test” or the “Alice/Mayo framework.”15 The Court’s decisions have been widely
recognized to effect a major change in the scope of patentable subject matter, restricting the sorts
of inventions that are patentable in the United States.16 The Alice/Mayo framework has thus
shifted, for better or worse, the balance between encouraging innovation and the social costs of
exclusive rights that is at the heart of patent law.17 The effects of this change have been
particularly pronounced for computer technologies and biomedical technologies.18
As a result, there is a significant and ongoing debate about the Alice/Mayo framework, with a
number of patent law stakeholders questioning the Court’s patentable subject matter rulings.19
Critics argue that the Alice/Mayo framework is vague, unpredictable, and not administrable;20

10 9.

Diehr, 450 U.S. at 185.

10. Bilski v. Kappos, 561 U.S. 593, 602 (2010) (citing Le Roy v. Tatham, 55 U.S. (14 How.) 156, 174–75 (1853)). Bilski v. Kappos, 561 U.S. 593, 602 (2010) (citing Le Roy v. Tatham, 55 U.S. (14 How.) 156, 174–75 (1853)).
11 Id. at 611–12.
12 11.

Id. at 611–12.

12. Mayo Collaborative Servs. v. Prometheus Labs., Inc., 566 U.S. 66, 77–80 (2012). Mayo Collaborative Servs. v. Prometheus Labs., Inc., 566 U.S. 66, 77–80 (2012).
13 Ass’ 13. Ass'n for Molecular Pathology v. Myriad Genetics, Inc., 569 U.S. 576, 590–94 (2013).n for Molecular Pathology v. Myriad Genetics, Inc., 569 U.S. 576, 590–94 (2013).
14 14. Alice Corp. Pty. v. CLS Bank Int Alice Corp. Pty. v. CLS Bank Int’'l, 573 U.S. 208, 218–26 (2014).l, 573 U.S. 208, 218–26 (2014).
15 15. See, e.g., Aatrix Software, Inc. v. Green Shades Software, Inc., 882 F.3d 1121, 1126, 1128 (Fed. Cir. 2018) (referring , Aatrix Software, Inc. v. Green Shades Software, Inc., 882 F.3d 1121, 1126, 1128 (Fed. Cir. 2018) (referring
to the inquiry as the to the inquiry as the “"Alice//Mayo testtest”" or the or the “"Alice//Mayo analysisanalysis”"). The Supreme Court refers to the two-step process ). The Supreme Court refers to the two-step process
first set forth in first set forth in Mayo as a as a “"framework.framework.”" Alice, 573 U.S. at 217., 573 U.S. at 217.
16 See U.S. PATENT & TRADEMARK OFF., PATENT ELIGIBLE SUBJECT MATTER: REPORT ON VIEWS AND
RECOMMENDATIONS FROM THE PUBLIC 16. See U.S. Patent & Trademark Off., Patent Eligible Subject Matter: Report on Views and Recommendations from the Public 23 (2017), https://www.uspto.gov/sites/default/files/documents/101- 23 (2017), https://www.uspto.gov/sites/default/files/documents/101-
Report_FINAL.pdf [hereinafter Report_FINAL.pdf [hereinafter PTO PSM REPORT] (“USPTO PSM Report] ("In general, commentators agreed that the Court decisions in In general, commentators agreed that the Court decisions in
Bilski, , Mayo, , Myriad, and , and Alice have had a significant impact on the scope of patent eligible subject matter. have had a significant impact on the scope of patent eligible subject matter.”"); Jeffrey ); Jeffrey
A. Lefstin et al., A. Lefstin et al., Final Report of the Berkeley Center for Law & Technology Section 101 Workshop: Addressing Patent
Eligibility Challenges, 33 , 33 BERKELEY TECHBerkeley Tech. L.J. 551, 555–59 (2018) [hereinafter . L.J. 551, 555–59 (2018) [hereinafter BCLT ReportReport] (describing these ] (describing these
Supreme Court opinions as a Supreme Court opinions as a “"sea-changesea-change”).
17"). 17. See Bonito Boats, Inc. v. Thunder Craft Boats, Inc., 489 U.S. 141, 146 (1989) Bonito Boats, Inc. v. Thunder Craft Boats, Inc., 489 U.S. 141, 146 (1989) ((“"From their inception, the federal From their inception, the federal
patent laws have embodied a careful balance between the need to promote innovation and the recognition that imitation patent laws have embodied a careful balance between the need to promote innovation and the recognition that imitation
and refinement through imitation are both necessary to invention itself and the very lifeblood of a competitive and refinement through imitation are both necessary to invention itself and the very lifeblood of a competitive
economy.economy.”"); Mark A. Lemley, ); Mark A. Lemley, Property, Intellectual Property, and Free Riding, 83 , 83 TEXTex. L. . L. REVRev. 1031, 1031 (2005) . 1031, 1031 (2005)
(“("[Traditionally,] the proper goal of intellectual property law is to give as little protection as possible consistent with [Traditionally,] the proper goal of intellectual property law is to give as little protection as possible consistent with
encouraging innovation.encouraging innovation.”"). 18. ).
18 See USPTO PSM Report PTO PSM REPORT, , supra note 16,note 16, at 34–35 (finding at 34–35 (finding “"a general consensus that two industries have been most a general consensus that two industries have been most
directly affected by the recent Supreme Court jurisprudence: life sciences and computer-related technologiesdirectly affected by the recent Supreme Court jurisprudence: life sciences and computer-related technologies”"). 19. ).
19 See generally id. at 27–34 (summarizing public comments that the at 27–34 (summarizing public comments that the Alice/Mayo framework is legally flawed, overly framework is legally flawed, overly
broad, unpredictable, and harmful to innovation).broad, unpredictable, and harmful to innovation).
20 20. Id. at 29–30 (describing public views that the Supreme Court at 29–30 (describing public views that the Supreme Court “"has failed to articulate objective, predictable criteriahas failed to articulate objective, predictable criteria”
" for patentable subject matter); Hon. Paul R. Michel, for patentable subject matter); Hon. Paul R. Michel, The Supreme Court Saps Patent Certainty, 82 , 82 GEO. WASH. L. REV.
Geo. Wash. L. Rev. 1751, 1758 (2014) (criticizing Court1751, 1758 (2014) (criticizing Court’'s modern Section 101 jurisprudence as s modern Section 101 jurisprudence as “"subjective,subjective,” “" "indeterminate,indeterminate,”" and and “"highly unpredictable"); David O. Taylor, Confusing Patent Eligibility, 84 Tenn. L. Revhighly
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muddies patent law by confusing patent eligibility with distinct patent law concerns, such as
nonobviousness;21 reduces incentives to innovate and invest in particular industries, such as
biotechnology;22 or puts U.S. industry at a disadvantage with international competitors.23 Other
stakeholders defend the Alice/Mayo framework, arguing that the Court’s decisions are a part of
the ordinary common law development of Section 101;24 an important tool for combating
unmeritorious litigation25 or preventing overbroad or otherwise harmful patents;26 or beneficial to
American consumers by lowering prices.27
In response to stakeholder concerns, there have been several recent administrative and legislative
developments that aim to clarify or reform the law of Section 101. In 2019, the Patent and
Trademark Office (PTO) issued Revised Patent Subject Matter Eligibility Guidance designed to
assist PTO patent examiners in determining patent eligibility with greater clarity and
predictability.28 In the 116th Congress, Senators Thom Tillis and Chris Coons, along with
Representatives Doug Collins, Hank Johnson, and Steve Stivers, released a “bipartisan, bicameral

unpredictable”); David O. Taylor, Confusing Patent Eligibility, 84 TENN. L. REV. 157, 158–60 (2016) (arguing that the . 157, 158–60 (2016) (arguing that the
Supreme CourtSupreme Court’'s Section 101 jurisprudence has created a s Section 101 jurisprudence has created a “"crisis of confusioncrisis of confusion”" in patent law and that the doctrine in patent law and that the doctrine
“"lacks administrabilitylacks administrability”).
21"). 21. See USPTO PSM Report PTO PSM REPORT, , supra note 16,note 16, at 31–32; Michael Risch, at 31–32; Michael Risch, Everything Is Patentable, 75 , 75 TENNTenn. L. . L. REVRev. 591, . 591,
598–606 (2008) (arguing that patentability criteria such as obviousness, novelty, utility, inventorship, written 598–606 (2008) (arguing that patentability criteria such as obviousness, novelty, utility, inventorship, written
description, and enablement motivate the Supreme Courtdescription, and enablement motivate the Supreme Court’'s patentable subject matter decisions). s patentable subject matter decisions). But see Mark A. Mark A.
Lemley et al., Lemley et al., Life After Bilski, 63 Bilski, 63 STANStan. L. . L. REVRev. 1315, 1319–32 (2011) (arguing that the preemption/overbreadth . 1315, 1319–32 (2011) (arguing that the preemption/overbreadth
concerns driving Section 101 are distinct from disclosure and definiteness concerns under Section 112).concerns driving Section 101 are distinct from disclosure and definiteness concerns under Section 112).
22 22. See, e.g., , PTO PSM REPORTUSPTO PSM Report, , supra note 16,note 16, at 32–33, 35–38; at 32–33, 35–38; BCLT Report, , supra note 16,note 16, at 582–84; Taylor at 582–84; Taylor, supra
note 20,note 20, at 240 ( at 240 (“"[The [The Alice/Mayo framework] substantially reduces incentives to invest in research and development, framework] substantially reduces incentives to invest in research and development,
particularly in the biotechnology and software technology areas.particularly in the biotechnology and software technology areas.”).
23"). 23. See USPTO PSM Report PTO PSM REPORT, , supra note 16,note 16, at 34; Ryan Davis, at 34; Ryan Davis, Kappos Calls for Abolition of Section 101 of Patent Act, Act,
LAW360Law360 (Apr. 12, 2016), https://www.law360.com/articles/783604/kappos-calls-for-abolition-of-section-101-of-patent- (Apr. 12, 2016), https://www.law360.com/articles/783604/kappos-calls-for-abolition-of-section-101-of-patent-
act (quoting former act (quoting former PTOUSPTO Director David Kappos as stating that international competitors Director David Kappos as stating that international competitors “"no longer have to steal U.S. no longer have to steal U.S.
technology in [biotechnology and software], since they can now take it for freetechnology in [biotechnology and software], since they can now take it for free”"); Robert L. Stoll, ); Robert L. Stoll, Courts Are Making
Bad Patent Law, , THE HILLThe Hill (July 16, 2015), https://thehill.com/blogs/pundits-blog/the-judiciary/248054-courts-are- (July 16, 2015), https://thehill.com/blogs/pundits-blog/the-judiciary/248054-courts-are-
making-bad-patent-lawmaking-bad-patent-law (" (“The courtsThe courts’' focus on subject matter eligibility as a mechanism to deny patents for [inventions focus on subject matter eligibility as a mechanism to deny patents for [inventions
in diagnostics and personalized medicine] will drive investment into research in these technologies to other areas. We in diagnostics and personalized medicine] will drive investment into research in these technologies to other areas. We
will lose our edge in the world . . . .will lose our edge in the world . . . .”).
24"). 24. See USPTO PSM Report PTO PSM REPORT, supra note 16, at 23–24.
25, supra note 16, at 23–24. 25. See id. at 24; at 24; BCLT Report, , supra note 16,note 16, at 555 ( at 555 (“"Many technology companies that rely on software innovation . . . Many technology companies that rely on software innovation . . .
welcomed the tightening of patent eligibility standards on software claims and the opportunity to seek early dismissals welcomed the tightening of patent eligibility standards on software claims and the opportunity to seek early dismissals
of lawsuits.of lawsuits.”"); Paul R. Gugliuzza, ); Paul R. Gugliuzza, Quick Decisions in Patent Cases, 106 , 106 GEOGeo. L.J. 619, 652–53 (2018) (. L.J. 619, 652–53 (2018) (“"The The
invigoration of the [patent] eligibility requirement can help courts resolve infringement disputes more quickly and invigoration of the [patent] eligibility requirement can help courts resolve infringement disputes more quickly and
cheaply by allowing validity to be resolved on the pleadings as a matter of law.cheaply by allowing validity to be resolved on the pleadings as a matter of law.”).
26"). 26. See The State of Patent Eligibility in America: Part I: Hearing Before the S. Judiciary Comm., Subcomm. on
Intellectual Property, 116th Cong. (2019) (statement of Prof. Joshua D. Sarnoff, DePaul University College of Law), at , 116th Cong. (2019) (statement of Prof. Joshua D. Sarnoff, DePaul University College of Law), at
3–8, https://www.judiciary.senate.gov/download/sarnoff-testimony [hereinafter Sarnoff Testimony]; 3–8, https://www.judiciary.senate.gov/download/sarnoff-testimony [hereinafter Sarnoff Testimony]; accord Mayo Mayo
Collaborative Servs. v. Prometheus Labs., Inc., 566 U.S. 66, 86 (2012) (Collaborative Servs. v. Prometheus Labs., Inc., 566 U.S. 66, 86 (2012) (“"[E]ven though rewarding with patents those [E]ven though rewarding with patents those
who discover new laws of nature and the like might well encourage their discovery, those laws and principles, who discover new laws of nature and the like might well encourage their discovery, those laws and principles,
considered generally, are the basic tools of scientific and technological work. And so there is a danger that the grant of considered generally, are the basic tools of scientific and technological work. And so there is a danger that the grant of
patents that tie up their use will inhibit future innovation . . . .patents that tie up their use will inhibit future innovation . . . .”" (citations omitted)); Lemley et al., (citations omitted)); Lemley et al., supra note 21,note 21, at at
1329 (arguing that Section 1011329 (arguing that Section 101’'s abstract ideas doctrine is s abstract ideas doctrine is “"about encouraging cumulative innovation and furthering about encouraging cumulative innovation and furthering
societal norms regarding access to knowledgesocietal norms regarding access to knowledge”).
27 PTO PSM REPORT, supra note 16, at 27.
28"). 27.

USPTO PSM Report, supra note 16, at 27.

28. Notice, 2019 Revised Patent Subject Matter Eligibility Guidance, 84 Fed. Reg. 50 (Jan. 7, 2019). Notice, 2019 Revised Patent Subject Matter Eligibility Guidance, 84 Fed. Reg. 50 (Jan. 7, 2019). PTOThe USPTO subsequently subsequently
issued an update to this guidance in October 2019. issued an update to this guidance in October 2019. See U.S. U.S. PAT. & TRADEMARK OFFPat. & Trademark Off., ., October 2019 Update: Subject
Matter Eligibility (Oct. 2019), (Oct. 2019), https://www.uspto.gov/sites/default/files/documents/peg_oct_2019_update.pdf. 29. See generally Sen. Chris Coons & Sen. Thom Tillis, What Coons and Tillis Learned at Patent Reform Hearings, Law360 (June 21, 2019), https://www.uspto.gov/sites/default/files/documents/peg_oct_2019_update.pdf.
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framework” for legislative Section 101 reform,29 and a draft bill to reform Section 101.30 After the
release of the draft bill, the Senate Judiciary Committee’s Intellectual Property Subcommittee
held three public hearings on Section 101 reform.31 These efforts did not result in formal
legislation introduced by these Members during the 116th Congress. In the 117th Congress,
Senator Tillis32 and Representative Thomas Massie33 have introduced bills on patent-eligible
subject matter.
This report provides the necessary background and context to understand the legal and practical
effects that these legislative reforms would have if enacted. First, the report reviews the basic
legal principles of the U.S. patent system. Second, it examines the historical development and
current state of patentable subject matter law. Third, it reviews several articulated rationales for
Section 101 and potential options for Section 101 reform. Finally, it examines recent judicial,
administrative, and legislative developments concerning patent-eligible subject matter, including
the proposed legislative reforms to Section 101.
This report focuses on patent-eligible subject matter reform from a legal perspective. For an
analysis of these issues as they relate to innovation policy, see CRS Report R47267, Patents and
Innovation Policy, by Emily G. Blevins.
Patent Law Background
Congress’s authority to grant patents derives from the Intellectual Property (IP) Clause of the
U.S. Constitution, which grants Congress the power “[t]o promote the Progress of Science and
useful Arts, by securing for limited Times to . . . Inventors the exclusive Right to their . . .
Discoveries.”34 Patents are generally available to any person who “invents or discovers any new

29 Press Release, Office of Sen. Thom Tillis, Sens. Tillis and Coons and Reps. Collins, Johnson, and Stivers Release
Section 101 Patent Reform Framework (Apr. 17, 2019), https://www.tillis.senate.gov/2019/4/sens-tillis-and-coons-and-
reps-collins-johnson-and-stivers-release-section-101-patent-reform-framework [hereinafter Sen. Tillis April 17 Press
Release]; Sen. Tillis et al., Draft Outline for Section 101 Reform, https://www.tillis.senate.gov/services/files/3491a23f-
09c3-4f4a-9a93-71292704c5b1 [hereinafter First Tillis-Coons Proposal].
30 Press Release, Office of Sen. Thom Tillis, Sens. Tillis and Coons and Reps. Collins, Johnson, and Stivers Release
Draft Bill Text to Reform Section 101 of the Patent Act (May 22, 2019), https://www.tillis.senate.gov/2019/5/sens-
tillis-and-coons-and-reps-collins-johnson-and-stivers-release-draft-bill-text-to-reform-section-101-of-the-patent-act
[hereinafter Sen. Tillis May 22 Press Release]; Sen. Tillis et al., Draft Bill for Section 101 Reform,
https://www.tillis.senate.gov/services/files/E8ED2188-DC15-4876-8F51-A03CF4A63E26 [hereinafter Second Tillis-
Coons Proposal].
31 See Sen. Chris Coons & Sen. Thom Tillis, What Coons and Tillis Learned at Patent Reform Hearings, LAW360 (June
21, 2019), https://www.law360.com/articles/1171672/. Video of the hearings and the written testimony are available https://www.law360.com/articles/1171672/. Video of the hearings and the written testimony are available
online. online. See The State of Patent Eligibility in America: Part I: Hearing Before the S. Judiciary Comm., Subcomm. on
Intellectual Property, 116th Cong. (2019), https://www.judiciary.senate.gov/meetings/the-state-of-patent-eligibility-in-, 116th Cong. (2019), https://www.judiciary.senate.gov/meetings/the-state-of-patent-eligibility-in-
america-part-i; america-part-i; The State of PatentPatent Eligibility in America: Part II: Hearing Before the S. Judiciary Comm., Subcomm.
on Intellectual Property, 116th Cong. (2019), https://www.judiciary.senate.gov/meetings/the-state-of-patent-eligibility-, 116th Cong. (2019), https://www.judiciary.senate.gov/meetings/the-state-of-patent-eligibility-
in-america-part-ii;in-america-part-ii; The State of Patent Eligibility in America: Part IIIIII: Hearing Before the S. Judiciary Comm.,
Subcomm. on Intellectual Property, 116th Cong. (2019), https://www.judiciary.senate.gov/meetings/the-state-of-patent-, 116th Cong. (2019), https://www.judiciary.senate.gov/meetings/the-state-of-patent-
eligibility-in-america-part-iii [hereinafter, collectively, eligibility-in-america-part-iii [hereinafter, collectively, Patent Eligibility Hearings].].
32 30. See Patent Eligibility Restoration Act of 2024, H.R. 9474, 118th Cong. (2024); Patent Eligibility Restoration Act of 2023, S. 2140, 118th Cong. (2023); Patent Eligibility Restoration Act of 2022, S. 4734, 117th Cong. (2022). Patent Eligibility Restoration Act of 2022, S. 4734, 117th Cong. (2022). 31. See
33 Restoring AmericaRestoring America’'s Leadership in Innovation Act of s Leadership in Innovation Act of 20212024, H.R. , H.R. 5874, 117th8134, 118th Cong. § 7 (2024); Restoring America's Leadership in Innovation Act of 2021, H.R. 5874, 117th Cong. § 7 (2021); Restoring America' Cong. § 7 (2021). Rep. Massie also
released similar proposals in past Congresses. See Restoring America’s Leadership in Innovation Act of 2020, H.R. s Leadership in Innovation Act of 2020, H.R.
7366, 116th Cong. § 7 (2020); Restoring America7366, 116th Cong. § 7 (2020); Restoring America’'s Leadership in Innovation Act of 2018, H.R. 6264, 115th Cong. § 7 s Leadership in Innovation Act of 2018, H.R. 6264, 115th Cong. § 7
(2018).
34 U.S. CONST. art. I, § 8, cl. 8.
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and useful process, machine, manufacture, or composition of matter, or any new and useful
improvement thereof.”35
Patent rights do not arise automatically. Rather, to obtain patent protection under the Patent Act,36
an inventor must formally apply for a patent with the PTO, beginning a process called patent
prosecution.37 During prosecution, a patent examiner at the PTO evaluates the patent application
to ensure that it meets all the applicable legal requirements to merit the grant of a patent.38 To be
patentable, an invention must be (1) directed at patent-eligible subject matter, (2) useful, (3) new,
(4) nonobvious, and (5) adequately disclosed and claimed in the patent application.39 If the PTO
finds these requirements met, it will issue (i.e., grant) the patent.40 Patents typically expire 20
years after the initial patent application.41
The current law of patent-eligible subject matter will be discussed separately in detail below.42
The remainder of this section briefly reviews the other requirements for patentability, the scope
and effect of patent claims, and the legal rights granted to the holder of a valid patent.
Requirements for Patentability
Section 101: Utility
Along with its subject matter requirements, Section 101 contains a requirement that a patented
invention must be “useful.”43 In particular, courts have held that an invention must have both a
specific and substantial utility to be patentable.44 The utility requirement derives from the
Constitution’s command that patent laws exist to “promote the Progress of . . . useful Arts.”45 The
constitutional purpose of patent law thus requires a “benefit derived by the public from an
invention with substantial utility,” where the “specific benefit exists in currently available
form.”46 This standard for utility is low, however, requiring only that the claimed invention have
some “significant and presently available benefit to the public” that “is not so vague as to be
meaningless.”47
Section 102: Novelty
Perhaps the most fundamental requirement for patentability is that the claimed invention must be
new. The PTO will not issue a patent if “the claimed invention was patented, described in a
printed publication, or in public use, on sale, or otherwise available to the public before the

35 35 U.S.C. § 101.
36(2018). 32.

For a succinct overview of this topic, see CRS In Focus IF12563, Patent-Eligible Subject Matter Reform: An Overview, by Emily G. Blevins and Kevin J. Hickey (2024).

33.

U.S. Const. art. I, § 8, cl. 8.

34.

35 U.S.C. § 101.

35. See Patent Act of 1952, Pub. L. No. 82-593, 66 Stat. 792 (codified as amended at 35 U.S.C. §§ 1–390). Patent Act of 1952, Pub. L. No. 82-593, 66 Stat. 792 (codified as amended at 35 U.S.C. §§ 1–390).
37 See General Information Concerning 36. See Applying for Patents, U.S. , U.S. PAT. & TRADEMARK OFF. (Oct. 2015)Pat. & Trademark Off., https://www.uspto.gov/patents/basics/apply (last visited Mar. 6, 2025). 37.

35 U.S.C. § 131.

38.

See id. §§ 101–103, 112.

39.

Id. § 131.

40.

Id. § 154(a)(2).

41. ,
https://www.uspto.gov/patents-getting-started/general-information-concerning-patents.
38 35 U.S.C. § 131.
39 See id. §§ 101–103, 112.
40 Id. § 131.
41 Id. § 154(a)(2).
42 See infra “The Current See infra "The Law of Section 101.”
43 35 U.S.C. § 101.
44." 42.

35 U.S.C. § 101.

43. Brenner v. Manson, 383 U.S. 519, 534–35 (1966); Brenner v. Manson, 383 U.S. 519, 534–35 (1966); In re Fisher, 421 F.3d 1365, 1371 (Fed. Cir. 2005). Fisher, 421 F.3d 1365, 1371 (Fed. Cir. 2005).
45 44. Stiftung v. Renishaw PLC, 945 F.2d 1173, 1180 (Fed. Cir. 1991) (citing Stiftung v. Renishaw PLC, 945 F.2d 1173, 1180 (Fed. Cir. 1991) (citing Brenner, 383 U.S. at 528–29)., 383 U.S. at 528–29).
46 45.

Brenner, 383 U.S. at 534–35.

46.

In re Fisher, 421 F.3d at 1371–72.

47. Brenner, 383 U.S. at 534–35.
47 In re Fisher, 421 F.3d at 1371–72.
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effective filing date of the claimed invention.”48 In other words, if every limitation of the claimed
invention is already disclosed in the “prior art”—the information available to the public at the
time of the patent application—then the alleged inventor “has added nothing to the total stock of
knowledge,” and no valid patent may issue to her.49
Section 103: Nonobviousness
Even if a claimed invention is novel in the narrow sense that it is not “identically disclosed” in a
prior-art reference (such as an earlier patent or publication), the invention must further be
nonobvious to be patentable.50 Specifically, an invention cannot be patented if “the differences
between the claimed invention and the prior art are such that the claimed invention as a whole
would have been obvious . . . to a person having ordinary skill” in the relevant technology.51
When determining obviousness, courts also evaluate secondary considerations (also known as
“objective indicia”) of nonobviousness such as “commercial success, long felt but unsolved
needs, [or] failure of others . . . to give light to the circumstances surrounding the origin of the
subject matter sought to be patented.”52 By its nature, obviousness is an “expansive and flexible”
inquiry that cannot be reduced to narrow, rigid tests.53 Nonetheless, if an invention merely
combines “familiar elements according to known methods,” yielding only “predictable results,” it
is likely to be obvious.54
Section 112(a): Written Description, Enablement, Best Mode
Finally, the Patent Act imposes several requirements relating to the technical disclosures in the
patent application. These provisions are intended to ensure that the patent adequately describes
the invention such that the public can use the invention after the expiration of the patent term.55
Section 112(a) of the Patent Act requires that patents must contain a “specification” that includes
a written description of the invention, and of the manner and process of making and using
it, in such full, clear, concise, and exact terms as to enable any person skilled in the art to
. . . make and use the same, and shall set forth the best mode contemplated by
the inventor or joint inventor of carrying out the invention.56
This statutory language yields three basic disclosure requirements for patentability.57 First, to
satisfy the written description requirement, the specification must “reasonably convey[] to those

48 35 U.S.C. § 102(a)(1). There are certain exceptions to this requirement when, for example, the prior-art disclosure 35 U.S.C. § 102(a)(1). There are certain exceptions to this requirement when, for example, the prior-art disclosure
derives from the inventor and the patent application is made within one year of the disclosure. derives from the inventor and the patent application is made within one year of the disclosure. Id. § 102(b)(1). § 102(b)(1).
49 48. Great Atl. & Pac. Tea Co. v. Supermarket Equip. Corp., 340 U.S. 147, 153 (1950); Graham v. John Deere Co. of Great Atl. & Pac. Tea Co. v. Supermarket Equip. Corp., 340 U.S. 147, 153 (1950); Graham v. John Deere Co. of
Kan. City, 383 U.S. 1, 6 (1966) (Kan. City, 383 U.S. 1, 6 (1966) (“"Congress may not authorize the issuance of patents whose effects are to remove Congress may not authorize the issuance of patents whose effects are to remove
existent knowledge from the public domain, or to restrict free access to materials already available.existent knowledge from the public domain, or to restrict free access to materials already available.”).
50 35 U.S.C. § 103.
51"). 49.

35 U.S.C. § 103.

50. Id. Patent law often relies on the concept of a Patent law often relies on the concept of a “"person having ordinary skill in the art,person having ordinary skill in the art,”" a a “"hypothetical personhypothetical person”" with a with a
typical level of skill in the relevant technology who is typical level of skill in the relevant technology who is “"presumed to be aware of all the pertinent prior artpresumed to be aware of all the pertinent prior art”" in the in the
particular field. particular field. See Standard Oil Co. v. Am. Cyanamid Co., 774 F.2d 448, 454 (Fed. Cir. 1985).Standard Oil Co. v. Am. Cyanamid Co., 774 F.2d 448, 454 (Fed. Cir. 1985).
52 51. Graham, 383 U.S. at 17–18; , 383 U.S. at 17–18; see also Apple Inc. v. Samsung Elecs. Co., 839 F.3d 1034, 1048 (Fed. Cir. 2016) (en Apple Inc. v. Samsung Elecs. Co., 839 F.3d 1034, 1048 (Fed. Cir. 2016) (en
banc) (banc) (“"Objective indicia of nonobviousness must be considered in every case where present.).Objective indicia of nonobviousness must be considered in every case where present.).
53 KSR Int’ 52. KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398, 415–19 (2007).l Co. v. Teleflex Inc., 550 U.S. 398, 415–19 (2007).
54 Id. at 416.
55 53.

Id. at 416.

54. See Kewanee Oil Co. v. Bicron Corp., 416 U.S. 470, 480–81 (1974). Kewanee Oil Co. v. Bicron Corp., 416 U.S. 470, 480–81 (1974).
56 55. 35 U.S.C. § 112(a) (emphases added). 35 U.S.C. § 112(a) (emphases added).
57 56. See Festo Corp. v. Shoketsu Kinzoku Kogyo Kabushiki Co., 535 U.S. 722, 736 (2002); Ariad Pharms., Inc. v. Eli Festo Corp. v. Shoketsu Kinzoku Kogyo Kabushiki Co., 535 U.S. 722, 736 (2002); Ariad Pharms., Inc. v. Eli
Lilly & Co., 598 F.3d 1336, 1344 (Fed. Cir. 2010) (en banc).Lilly & Co., 598 F.3d 1336, 1344 (Fed. Cir. 2010) (en banc).
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skilled in the art that the inventor had possession of the claimed subject matter as of the filing
date” of the patent application.58 Second, to satisfy the enablement requirement, the specification
must contain enough information to teach a person skilled in the art how “to make and use the
invention without undue experimentation.”59 Finally, to satisfy the best mode requirement, if the
inventor knew of a preferred way of practicing her invention at the time of the patent application,
the specification must disclose that “preferred embodiment[]” of the invention. 60
Patent Claims
Section 112(b): Definiteness
If granted, the legal scope of the patent is defined by the patent claims, a sequence of statements
that formally set forth the patentee’s asserted rights. In essence, while the specification explains
the invention in a technical sense, the claims set forth the legal effect of the patent.61 Much as a
deed may describe the boundaries of a tract of land, the claims define the “metes and bounds” of
the patent right.62 Patent claims must be sufficiently definite to be valid—that is, they must
“particularly point[] out and distinctly claim[] the subject matter which the inventor . . . regards as
the invention.”63 In other words, when the claims are read in context, they must “inform, with
reasonable certainty, those skilled in the art about the scope of the invention.”64
Section 112(f): Functional Claiming
For the most part, the current Patent Act uses a system of peripheral claiming, in which the patent
claims formally set out the outer boundaries of the patentee’s rights.65 However, the Patent Act

58 Ariad, 598 F.3d at 1351.
59 57.

Ariad, 598 F.3d at 1351.

58. In re Wands, 858 F.2d 731, 735 (Fed. Cir. 1988). Wands, 858 F.2d 731, 735 (Fed. Cir. 1988).
60 59. Eli Lilly & Co. v. Barr Labs., Inc., 251 F.3d 955, 963 (Fed. Cir. 2001). Failure to disclose the best mode is not a basis Eli Lilly & Co. v. Barr Labs., Inc., 251 F.3d 955, 963 (Fed. Cir. 2001). Failure to disclose the best mode is not a basis
on which a patent claim can be invalidated in subsequent patent infringement proceedings. 35 U.S.C. § 282(b)(3)(A).on which a patent claim can be invalidated in subsequent patent infringement proceedings. 35 U.S.C. § 282(b)(3)(A).
61 60. See Ariad,, 598 F.3d at 1347 (Fed. Cir. 2010); 598 F.3d at 1347 (Fed. Cir. 2010); In re Vamco Mach. & Tool, Inc., 752 F.2d 1564, 1577 n.5 (Fed. Cir. Vamco Mach. & Tool, Inc., 752 F.2d 1564, 1577 n.5 (Fed. Cir.
1985).1985).
62 61. Corning Glass Works v. Sumitomo Elec. U.S.A., Inc., 868 F.2d 1251, 1257 (Fed. Cir. 1989). Corning Glass Works v. Sumitomo Elec. U.S.A., Inc., 868 F.2d 1251, 1257 (Fed. Cir. 1989).
63 62. 35 U.S.C. § 112(b); Laitram Corp. v. NEC Corp., 163 F.3d 1342, 1347 (Fed. Cir. 1998) ( 35 U.S.C. § 112(b); Laitram Corp. v. NEC Corp., 163 F.3d 1342, 1347 (Fed. Cir. 1998) (“"[I]t is the [I]t is the claims, not the , not the
written description, which define the scope of the patent right.written description, which define the scope of the patent right.”).
64"). 63. Nautilus, Inc. v. Biosig Instruments, Inc., 572 U.S. 898, 901 (2014). Nautilus, Inc. v. Biosig Instruments, Inc., 572 U.S. 898, 901 (2014).
65 64. See 35 U.S.C. § 112(b); Mark A. Lemley, 35 U.S.C. § 112(b); Mark A. Lemley, Software Patents and the Return of Functional Claiming, 2013 , 2013 WISWis. L. . L.
REVRev. 905, 911 (2013) (. 905, 911 (2013) (“"Today, peripheral claiming is universal [in patent law]; patentees write claims in an effort to Today, peripheral claiming is universal [in patent law]; patentees write claims in an effort to
define the outer boundaries of their invention.define the outer boundaries of their invention.”"); Jeanne C. Fromer, ); Jeanne C. Fromer, Claiming Intellectual Property, 76 U. , 76 U. CHIChi. L. . L. REV.
Rev. 719, 725–30 (2009) (explaining the distinction between peripheral and central claiming systems for intellectual 719, 725–30 (2009) (explaining the distinction between peripheral and central claiming systems for intellectual
property). Until the late 19th century, however, central claiming prevailed: the patentee had only to describe the core property). Until the late 19th century, however, central claiming prevailed: the patentee had only to describe the core
principle or an example of his invention, and courts would decide whether the accused infringerprinciple or an example of his invention, and courts would decide whether the accused infringer’'s product or method s product or method
was sufficiently similar to the patenteewas sufficiently similar to the patentee’'s invention to infringe the patent. s invention to infringe the patent. See Lemley, Lemley, supra, at 910–11; Fromer, , at 910–11; Fromer, supra, ,
at 731–33. Peripheral claiming began as a defensive strategy by patentees to describe their invention at a higher level of at 731–33. Peripheral claiming began as a defensive strategy by patentees to describe their invention at a higher level of
generality, and the gradual switch toward the modern patent claiming was eventually codified in the Patent Act in 1870. generality, and the gradual switch toward the modern patent claiming was eventually codified in the Patent Act in 1870.
See An Act to revise, consolidate, and amend the Statutes relating to Patents and Copyrights, Pub. L. No. 41-230 § 26, An Act to revise, consolidate, and amend the Statutes relating to Patents and Copyrights, Pub. L. No. 41-230 § 26,
16 Stat. 198, 201 (1870) (requiring patent applicant to 16 Stat. 198, 201 (1870) (requiring patent applicant to “"particularly point out and distinctly claim the part, particularly point out and distinctly claim the part,
improvement, or combination which he claims as his invention or discoveryimprovement, or combination which he claims as his invention or discovery”"); ); see generally Fromer, Fromer, supra, at 731–35 , at 731–35
(reviewing American patent law(reviewing American patent law’'s historical shift from central to peripheral claiming); Dan L. Burk & Mark A. Lemley, s historical shift from central to peripheral claiming); Dan L. Burk & Mark A. Lemley,
Fence Posts or Sign Posts? Rethinking Patent Claim Construction, 157 U. , 157 U. PAPa. L. . L. REVRev. 1743, 1766–71 (2009) (same). . 1743, 1766–71 (2009) (same).
This account of patent-claiming history is somewhat simplified: notably, despite the 1870 statutory shift, the Patent Act This account of patent-claiming history is somewhat simplified: notably, despite the 1870 statutory shift, the Patent Act
retained (and retains) features of central claiming. retained (and retains) features of central claiming. See Burk & Lemley, Burk & Lemley, supra, at 1771 (, at 1771 (“"[I]t may be fairer to say that [I]t may be fairer to say that
during the twentieth century we had not a peripheral-claiming system, but a hybrid peripheral claiming system.during the twentieth century we had not a peripheral-claiming system, but a hybrid peripheral claiming system.”).
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still retains elements of its former system of central claiming, in which the patentee would
describe the core principles or examples of what he had invented, but need not formally delineate
the outer boundaries of his rights.66 For example, under the doctrine of equivalents, an accused
infringer may be found liable even if his product does not literally meet every element of the
patent claims, if the differences between a claim element and its alleged equivalent in the accused
product are “insubstantial.”67
A potential danger of a peripheral claiming system is that patentees may seek to claim more than
they invented by couching the patent claims in broad, functional language—that is, by claiming a
result or goal without limitation to any specific structure or device that accomplishes the result.68
In Halliburton Oil Well Cementing Co. v. Walker, the Supreme Court limited this practice,
invalidating as indefinite a “functional” patent claim, in which the invention—an apparatus for
determining the location of an obstruction in an oil well—was claimed not in terms of specific
machinery, but instead as a “means for” performing various functions.69
Functional claims (also known as “means-plus-function” claims) such as those in Halliburton
may be convenient for the patentee, who can express a claim element in terms of a general end,
rather than an “exhaustive list” of every possible apparatus that could be used to perform that
goal.70 On the other hand, as Halliburton recognized, functional claims may be overbroad and
ambiguous, or permit the patentee to claim more than he actually invented.71 In the Patent Act of
1952, Congress enacted current Section 112(f) as a compromise for functional claims, overruling
Halliburton72 but providing a standard to make functional claims more definite.73
Under Section 112(f), a patentee may opt to express a claim element as “a means or step for
performing a specified function without the recital of structure, material, or acts in support
thereof.”74 If the patentee chooses to claim functionally, however, the claim is construed not to
cover all possible means of performing the function, but only “the corresponding structure,
material, or acts described in the specification and equivalents thereof.”75 Courts have held that a

66"). 65. See Warner-Jenkinson Co. v. Hilton Davis Chemical Co., 520 U.S. 17, 27 n.4 (1997) (Warner-Jenkinson Co. v. Hilton Davis Chemical Co., 520 U.S. 17, 27 n.4 (1997) (“"[T]he abandonment of [T]he abandonment of
‘central’'central' claiming [in American patent law] may be overstated. claiming [in American patent law] may be overstated.”");); Fromer, Fromer, supra note 65,note 64, at 735–41 (describing at 735–41 (describing
“vestiges”"vestiges" of central claiming in the modern Patent Act). of central claiming in the modern Patent Act).
67 66. See Warner-Jenkinson, 520 U.S. at 39–40; Graver Tank & Mfg. Co. v. Linde Co., 339 U.S. 605, 608–09 (1950) , 520 U.S. at 39–40; Graver Tank & Mfg. Co. v. Linde Co., 339 U.S. 605, 608–09 (1950)
(laying out factors to consider in determining equivalence).(laying out factors to consider in determining equivalence).
68 67. See Lemley, Lemley, supra note note 65, 64, at 911–13. Such claiming should in theory be prohibited on novelty or enablement at 911–13. Such claiming should in theory be prohibited on novelty or enablement
grounds, grounds, see 35 U.S.C. §§ 102, 112(a), but the problem persists, for example, in modern software patents. 35 U.S.C. §§ 102, 112(a), but the problem persists, for example, in modern software patents. See Lemley, Lemley,
supra note 65,note 64, at 921–23 (citing examples). at 921–23 (citing examples).
69 68. See 329 U.S. 1, 8–9, 12–13 (1946).329 U.S. 1, 8–9, 12–13 (1946).
70 69. Stephen Winslow, Stephen Winslow, Means for Improving Modern Functional Patent Claiming, 98 , 98 GEOGeo. L.J. 1891, 1892 (2010) (. L.J. 1891, 1892 (2010) (“A
"A patent can be clearer, more concise, and more comprehensible when the patentee drafts her claims using language patent can be clearer, more concise, and more comprehensible when the patentee drafts her claims using language
describing what a particular element does, rather than giving an exhaustive list of the various structures that could describing what a particular element does, rather than giving an exhaustive list of the various structures that could
provide that function within her invention.provide that function within her invention.”).
71"). 70. See Halliburton, 329 U.S. at 12., 329 U.S. at 12.
72 71. See Williamson v. Citrix Online, LLC, 792 F.3d 1339, 1347 (Fed. Cir. 2015) (en banc) (Williamson v. Citrix Online, LLC, 792 F.3d 1339, 1347 (Fed. Cir. 2015) (en banc) (“"In enacting [§ 112(f)], In enacting [§ 112(f)],
Congress struck a balance in allowing patentees to express a claim limitation by reciting a function to be performed Congress struck a balance in allowing patentees to express a claim limitation by reciting a function to be performed
rather than by reciting structure for performing that function, while placing specific constraints on how such a rather than by reciting structure for performing that function, while placing specific constraints on how such a
limitation is to be construed . . . .limitation is to be construed . . . .”"); P.J. ); P.J. FEDERICO, COMMENTARY ON THE NEW PATENT ACTFederico, Commentary on the New Patent Act (West 1954), (West 1954), reprinted in
75 J. 75 J. PAT. & TRADEMARK OFF. SOC’YPat. & Trademark Off. Soc'y 161, 186 (1993) (observing that 161, 186 (1993) (observing that “"[t]he last paragraph of section 112[t]he last paragraph of section 112”" means that means that
“"decisions such as that in [decisions such as that in [Halliburton Oil] are modified or rendered obsolete . . . .] are modified or rendered obsolete . . . .”).
73"). 72.

Valmont Indus. v. Reinke Mfg. Co., 983 F.2d 1039, 1042 (Fed. Cir. 1993).

73.

35 U.S.C. § 112(f).

74.

Id. (emphasis added).

75.

Williamson, 792 F.3d at 1348 (quoting Watts v. XL Sys., Inc., 232 F.3d 877, 880 (Fed. Cir. 2000)).

76.

Id.

77.

35 U.S.C. § 154(a).

78.

Id. § 154(b)(1).

79. Valmont Indus. v. Reinke Mfg. Co., 983 F.2d 1039, 1042 (Fed. Cir. 1993).
74 35 U.S.C. § 112(f).
75 Id. (emphasis added).
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patentee is presumed to invoke Section 112(f) when the term “means” is used in the claims.76
Conversely, there is a presumption that the patentee does not invoke Section 112(f) if she does not
use the term “means,” but that presumption may be overcome, such that Section 112(f) will apply
to any claim that fails to recite a “sufficiently definite structure” for performing a function.77
Rights of Patent Holders
With some exceptions, a patent is generally granted “for a term beginning on the date on which
the patent issues and ending 20 years from the date on which the application for the patent was
filed.”78 The Patent Act includes provisions that may modify the 20-year term, including to
account for excessive delays in patent examination at the PTO,79 or delays associated with
obtaining marketing approval from other federal agencies.80
Once granted, a valid patent gives the patent holder the exclusive right to make, use, sell, or
import the invention in the United States until the patent expires.81 Any other person who
practices the invention (i.e., makes, uses, sells, offers to sell, or imports it) without permission
from the patent holder infringes the patent and may be liable for monetary damages and
injunctive relief if sued by the patentee.82 To obtain relief from infringement, the patentee must
generally sue in court.83 Patent law is an area of exclusive federal jurisdiction,84 and the
traditional forum for most patent disputes is federal district court.85 Although patent suits may be
filed in any district court across the country with jurisdiction over the defendant and proper
venue,86 a single specialized court, the U.S. Court of Appeals for the Federal Circuit (Federal
Circuit), hears all appeals in patent cases.87

76 Williamson, 792 F.3d at 1348 (quoting Watts v. XL Sys., Inc., 232 F.3d 877, 880 (Fed. Cir. 2000)).
77 Id.
78 35 U.S.C. § 154(a).
79 Id. § 154(b)(1).
80 Id. § 156. In the pharmaceutical context,§ 156. In the pharmaceutical context, patents claiming a drug product or medical device (or a method of using or patents claiming a drug product or medical device (or a method of using or
manufacturing the same) may be extended for up to five years to account for delays in obtaining regulatory approval, if manufacturing the same) may be extended for up to five years to account for delays in obtaining regulatory approval, if
certain statutory conditions are met.certain statutory conditions are met. See Eli Lilly & Co. v. Medtronic, Inc., 496 U.S. 661, 670–71 (1990);Eli Lilly & Co. v. Medtronic, Inc., 496 U.S. 661, 670–71 (1990); Merck & Co. Merck & Co.
v. Hi-Tech Pharmacal Co., 482 F.3d 1317, 1320–21 (Fed. Cir. 2007); Stephanie Plamondon Bair, v. Hi-Tech Pharmacal Co., 482 F.3d 1317, 1320–21 (Fed. Cir. 2007); Stephanie Plamondon Bair, Adjustments,
Extensions, Disclaimers, and Continuations: When Do Patent Term Adjustments Make Sense?, 41 , 41 CAPCap. U. L. . U. L. REVRev. 445, . 445,
460 (2013).460 (2013).
81 80. 35 U.S.C. § 271(a). 35 U.S.C. § 271(a).
82 81. Id. §§ 271, 281, 283–85. §§ 271, 281, 283–85.
83 35 U.S.C. § 281.
84 28 U.S.C. § 1338.
85 In 2018, roughly 3,447 82.

35 U.S.C. § 281.

83.

28 U.S.C. § 1338.

84. In 2023, roughly 3,108 patent lawsuits were filed in federal district courts, as compared to 1, patent lawsuits were filed in federal district courts, as compared to 1,717192 petitions filed before the Patent before the Patent
Trial and Appeal Board (PTAB). Trial and Appeal Board (PTAB). See 20182023 Patent Dispute Report: Year in Review, , UNIFIED PATENTS (Jan. 2, 2019Unified Patents (Jan. 8, 2024), ),
https://www.unifiedpatents.com/https://www.unifiedpatents.com/news/2019/1/2/2018-insights/2024/1/8/patent-dispute-report-patent-dispute-report-year2023-in-review-in-review [hereinafter 2018 Patent
Dispute Year in Review]. The third main forum for patent disputes is the International Trade Commission (ITC), which . The third main forum for patent disputes is the International Trade Commission (ITC), which
has authority to conduct administrative trials (called has authority to conduct administrative trials (called “"Section 337 investigationsSection 337 investigations”") into whether imported goods violate ) into whether imported goods violate
patent and other intellectual property rights. patent and other intellectual property rights. See 19 U.S.C. § 1337. 19 U.S.C. § 1337.
86The ITC usually receives fewer than 100 complaints per year (and not all of these are patent cases). See Section 337 Statistics: Number of New, Completed, and Active Investigations by Fiscal Year (Updated Quarterly), ITC, https://www.usitc.gov/intellectual_property/337_statistics_number_new_completed_and_active.htm (last updated Feb. 3, 2025). 85. See generally TC Heartland LLC v. Kraft Foods Grp., 137 S. Ct. 1514, 1518–21 (2017) (addressing scope of patent TC Heartland LLC v. Kraft Foods Grp., 137 S. Ct. 1514, 1518–21 (2017) (addressing scope of patent
venue statute); Gunn v. Minton, 568 U.S. 251 (2013) (addressing scope of federal patent subject matter jurisdiction); venue statute); Gunn v. Minton, 568 U.S. 251 (2013) (addressing scope of federal patent subject matter jurisdiction);
Xilinx, Inc. v. Papst Licensing GmbH & Co. KG, 848 F.3d 1346 (Fed. Cir. 2017) (addressing personal jurisdiction in Xilinx, Inc. v. Papst Licensing GmbH & Co. KG, 848 F.3d 1346 (Fed. Cir. 2017) (addressing personal jurisdiction in
patent dispute).patent dispute).
87 86.

28 U.S.C. § 1295(a)(1).

87.

35 U.S.C. § 282(b)(1).

88. 28 U.S.C. § 1295(a)(1).
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Defending Against Patent Suits
Parties accused of patent infringement may defend on several grounds. First, the accused
infringer may claim an “absence of liability” because of noninfringement.88 In other words, even
presuming the patent is valid, the patentee may fail to prove that the activities of the accused
infringer fall within the scope of the patent claims—that is, the accused infringer is not making,
using, selling, or importing the patented invention.89 Second, although patents benefit from a
presumption of validity, the accused infringer may assert that the patent is invalid.90 To prove
invalidity, the accused infringer must show, by clear and convincing evidence, that the PTO
should not have granted the patent because it failed to meet the requirements for patentability.91
Thus, for example, the accused infringer may argue that the invention lacks novelty, is obvious, or
claims nonpatentable subject matter; that the patent fails to enable the invention; or that the patent
claims are indefinite.92 Finally, the accused infringer may assert as a defense that the patent is
unenforceable based on the inequitable or illegal activities of the patent holder, such as obtaining
the patent through fraud on the PTO.93 While the patent holders bears the burden of proving
infringement,94 the accused infringer bears the burden of proving invalidity or inequitable
conduct.95
Following the passage of the 2011 Leahy-Smith America Invents Act (AIA),96 the Patent Trial
and Appeal Board (PTAB) has become an increasingly important forum for patent disputes.97 The
AIA created several new administrative procedures for challenging patent validity, including (1)
post-grant review (PGR), which allows any person to challenge patent validity based on any of
the requirements of patentability if the PGR petition is filed within nine months of the patent’s
issuance;98 (2) inter partes review (IPR), which allows any person other than the patentee to
challenge patent validity on limited grounds (novelty or obviousness based on prior patents or
printed publications) at any time after nine months following the patent’s issuance;99 and (3) a
transitional program for covered business method patents (CBM), a PGR-like process limited to

88 35 U.S.C. § 282(b)(1).
89 To prove direct infringement, the plaintiff must show that each element contained in a patent claim is practiced by To prove direct infringement, the plaintiff must show that each element contained in a patent claim is practiced by
the alleged infringer, either literally or by an equivalent. Warner-Jenkinson Co. v. Hilton Davis Chem. Co., 520 U.S. the alleged infringer, either literally or by an equivalent. Warner-Jenkinson Co. v. Hilton Davis Chem. Co., 520 U.S.
17, 29–30 (1997). Often, whether or not the accused infringer17, 29–30 (1997). Often, whether or not the accused infringer’'s activities fall within the patent claims depends upon s activities fall within the patent claims depends upon
claim construction: how the words used in the patent claims are interpreted. : how the words used in the patent claims are interpreted. See generally Markman v. Westview Markman v. Westview
Instruments, Inc., 517 U.S. 370, 372–74 (1996); Phillips v. AWH Corp., 415 F.3d 1303, 1312–19 (Fed. Cir. 2005) (en Instruments, Inc., 517 U.S. 370, 372–74 (1996); Phillips v. AWH Corp., 415 F.3d 1303, 1312–19 (Fed. Cir. 2005) (en
banc).banc).
90 89. 35 U.S.C. § 282(a), (b)(2)–(3). 35 U.S.C. § 282(a), (b)(2)–(3).
91 90. Id. § 282(b)(2)–(3); Microsoft Corp. v. i4i Ltd. P § 282(b)(2)–(3); Microsoft Corp. v. i4i Ltd. P’'ship, 564 U.S. 91, 95–96 (2011).ship, 564 U.S. 91, 95–96 (2011).
92 91. See supra "“Requirements for Patentability.”
93." 92. 35 U.S.C. § 282(b)(1); Therasense, Inc. v. Becton, Dickinson & Co., 649 F.3d 1276, 1285, 1290–91 (Fed. Cir. 2011) 35 U.S.C. § 282(b)(1); Therasense, Inc. v. Becton, Dickinson & Co., 649 F.3d 1276, 1285, 1290–91 (Fed. Cir. 2011)
(en banc).(en banc).
94 93. Medtronic, Inc. v. Mirowski Fam. Ventures, LLC, 571 U.S. 191, 193 (2014). Medtronic, Inc. v. Mirowski Fam. Ventures, LLC, 571 U.S. 191, 193 (2014).
95 94. 35 U.S.C. § 282(a); 35 U.S.C. § 282(a); Therasense, 649 F.3d at 1291. 649 F.3d at 1291.
96 95. Pub. L. No. 112-29, 125 Stat. 284 (2011). Pub. L. No. 112-29, 125 Stat. 284 (2011).
97 See generally 96. See generally CRS Report R48016, The Patent Trial and Appeal Board and Inter Partes Review, by Christopher T. Zirpoli and Kevin J. Hickey (2024); Rochelle Cooper Dreyfuss, Giving the Federal Circuit a Run for Its Money: Challenging Patents in the Rochelle Cooper Dreyfuss, Giving the Federal Circuit a Run for Its Money: Challenging Patents in the
PTABPTAB, 91 Notre Dame L. Rev, 91 NOTRE DAME L. REV. 235, 249 (2015); CRS Report R44962, Patent Law: A Primer and Overview of
Emerging Issues, by Kevin J. Hickey at 6–9.
98. 235, 249 (2015). 97. 35 U.S.C. §§ 321–329. 35 U.S.C. §§ 321–329.
99 98. Id. §§ 311–319. §§ 311–319.
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certain patents claiming “business methods” that was available only through September 2020.100
Of these procedures, IPR is by far the most widely used.101
The Current Law of Section 101
At a general level, there are two basic requirements for an invention to claim patent-eligible
subject matter. First, the invention must fit into one or more of the four statutory categories in
Section 101—the claimed invention must be a (1) process, (2) machine, (3) manufacture, or (4)
composition of matter.102 Given the (intentionally) expansive nature of these terms, nearly all
claimed inventions will satisfy this requirement.103 Still, exceptions to this rule do exist. For
example, in In re Nuijten, the Federal Circuit held that a transitory electromagnetic signal was
neither a process, machine, manufacture, or composition of matter, and was therefore not patent-
eligible subject matter.104
Because most claimed inventions fit into one of the four statutory categories, the second
requirement tends to be more practically important, and receives more attention.105 The second
patentable subject matter requirement is that the invention cannot claim one of the judicially
created categories of ineligible subject matter. That is, the claimed invention must not be a (1) law
of nature, (2) natural phenomenon, or (3) abstract idea.106 As explained below, the modern
Supreme Court has articulated a two-step test for this second requirement, known as the
Alice/Mayo framework.107

100 Pub. L. No. 112-29, § 18, 125 Stat 284, 329–30 (2011) (not codified in U.S.C.).
101 See 2018 Patent Dispute Year in Review, supra note 85 (finding that IPRs constituted 93.9% of petitions submitted
to the PTAB in 2018).
102 35 U.S.C. § 101.
103 See Lemley et al., supra note 21, at 1328 (“ 99.

Pub. L. No. 112-29, § 18, 125 Stat 284, 329–30 (2011) (not codified in U.S.C.).

100.

See PTAB Trial Statistics: FY23 End of Year Outcome Roundup, USPTO, https://www.uspto.gov/sites/default/files/documents/ptab_aia_fy2023__roundup.pdf (last visited Mar. 6, 2025), at 3 (98% of petitions filed with PTAB in FY2023 were IPRs).

101.

35 U.S.C. § 311(b).

102.

35 U.S.C. § 101.

103. See Lemley et al., supra note 21, at 1328 ("[P]atent claims almost never fall [P]atent claims almost never fall outside of the four fundamental of the four fundamental
categories of § 101 . . . .categories of § 101 . . . .”).
104"). 104. 500 F.3d 1346, 1354–57 (Fed. Cir. 2007). 500 F.3d 1346, 1354–57 (Fed. Cir. 2007).
105 105. See Kevin Emerson Collins, Kevin Emerson Collins, Patent-Ineligibility As Counteraction, 94 , 94 WASHWash. U. L. . U. L. REVRev. 955, 968 (2017) . 955, 968 (2017)
(“("Contemporary debates over patent-ineligibility rarely parse the plain meanings of [the four statutory categories]. Contemporary debates over patent-ineligibility rarely parse the plain meanings of [the four statutory categories].
They focus instead on a set of judicial exclusions from patent-eligibility that are not expressly codified in the statute: They focus instead on a set of judicial exclusions from patent-eligibility that are not expressly codified in the statute:
laws of nature, products of nature, and abstract ideas . . . .laws of nature, products of nature, and abstract ideas . . . .”).
106"). 106. Diamond v. Diehr, 450 U.S. 175, 185 (1981). Diamond v. Diehr, 450 U.S. 175, 185 (1981). Diehr’'s modern distillation of patentable subject matter doctrine to s modern distillation of patentable subject matter doctrine to
these three categories is a somewhat simplified version of the doctrinethese three categories is a somewhat simplified version of the doctrine’'s historical development, which often identified s historical development, which often identified
patent-ineligible categories in addition to these three. patent-ineligible categories in addition to these three. See, e.g., Daniel J. Klein, , Daniel J. Klein, TheThe Integrity of Section 101: A ‘'New
and Useful’' Test for Patentable Subject Matter, 93 J. , 93 J. PAT. & TRADEMARK OFF. SOC’YPat. & Trademark Off. Soc'y 287, 288 (2011) (listing eight 287, 288 (2011) (listing eight
terms that the Court has used to denote patent-ineligible subject matter); Michel, terms that the Court has used to denote patent-ineligible subject matter); Michel, supra note 20,note 20, at 1757 (counting six at 1757 (counting six
categories of patent-ineligible subject matter); categories of patent-ineligible subject matter); accord Emily Michiko Morris, Emily Michiko Morris, Intuitive Patenting, 66 S.C. L. , 66 S.C. L. REVRev. 61, . 61,
66 n.31 (2014) (describing the Supreme Court66 n.31 (2014) (describing the Supreme Court’'s patentable subject matter jurisprudence as s patentable subject matter jurisprudence as “"insolubly murkyinsolubly murky”).
"). In addition to the three modern patent-ineligible categories and their close variants (such as In addition to the three modern patent-ineligible categories and their close variants (such as “"products of natureproducts of nature”" or or
“"physical phenomenaphysical phenomena”" as synonyms for natural phenomena, see Diamond v. Chakrabarty, 447 U.S. 303, 309, 313 as synonyms for natural phenomena, see Diamond v. Chakrabarty, 447 U.S. 303, 309, 313
(1980), or (1980), or “"scientific truthscientific truth”" as a synonym for a law of nature, see Mackay Radio & Tel. Co. v. Radio Corp. of Am., 306 as a synonym for a law of nature, see Mackay Radio & Tel. Co. v. Radio Corp. of Am., 306
U.S. 86, 94 (1939)), courts have at times referenced U.S. 86, 94 (1939)), courts have at times referenced “"principles,principles,” “" "natural agencies,natural agencies,” “" "functions of a machine,functions of a machine,” “" "effects effects
of a machine,of a machine,” “" "mathematical formulas,mathematical formulas,” “algorithms,” “" "algorithms," "mental processes,mental processes,” “" "mental steps,mental steps,”" and and “"printed matterprinted matter”" as as
patent-ineligible categories. patent-ineligible categories. See Le Roy v. Tatham, 55 U.S. 156, 175 (1852) ( Le Roy v. Tatham, 55 U.S. 156, 175 (1852) (“"principle[s]principle[s]”" and and “"natural agenciesnatural agencies”"); );
Corning v. Burden, 56 U.S. 252, 268 (1853) (Corning v. Burden, 56 U.S. 252, 268 (1853) (“"function or abstract effect of a machinefunction or abstract effect of a machine”"); Gottschalk v. Benson, 409 ); Gottschalk v. Benson, 409
U.S. 63, 67, 72 (1972) (U.S. 63, 67, 72 (1972) (“"mathematical formula,mathematical formula,” “algorithm,” “" "algorithm," "mental processesmental processes”"); Diamond v. Diehr, 450 U.S. 175, ); Diamond v. Diehr, 450 U.S. 175,
195–200 (1981) (Stevens, J., dissenting) (reviewing history of 195–200 (1981) (Stevens, J., dissenting) (reviewing history of “"mental stepsmental steps”" doctrine that prohibited patents on doctrine that prohibited patents on
“"processes involving mental operationsprocesses involving mental operations”"); Praxair Distribution, Inc. v. Mallinckrodt Hosp. Prod. IP Ltd., 890 F.3d ); Praxair Distribution, Inc. v. Mallinckrodt Hosp. Prod. IP Ltd., 890 F.3d
1024, 1031–33 (Fed. Cir. 2018) (1024, 1031–33 (Fed. Cir. 2018) (“"printed matterprinted matter”).
107"). 107. See infra "“The Modern Alice/Mayo Framework.”
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The Supreme Court has justified the three ineligible categories as necessary to prevent patent
monopolies on the “‘basic tools of scientific and technological work,’” which “might tend to
impede innovation more than it would tend to promote it.”108 Thus, the Court has explained that
“a new mineral discovered in the earth or a new plant found in the wild is not patentable subject
matter. Likewise, Einstein could not patent his celebrated law that E=mc2; nor could Newton have
patented the law of gravity.”109 At the same time, the Court has said that even if a mathematical
formula or law of nature is not patentable “in the abstract,” a practical application of such a
principle or law “to a new and useful end” is patent-eligible.110
Beyond such broad illustrations, it is not easy to define what an “abstract idea,” “law of nature,”
or “natural phenomenon” is.111 Because these exceptions to patent-eligible subject matter are
judicially created, they have no formal statutory definition; their meaning has instead been
developed through two centuries of case-by-case “common law” adjudication in the federal
courts.112 As a result, the scope of patentable subject matter has waxed and waned over time,
depending on the trends in judicial decisions.113
This section overviews the leading Supreme Court cases addressing patent-eligible subject matter,
beginning with formative cases from the 19th century and culminating in the series of 2010s
Supreme Court decisions that have led some to call for legislative reform of Section 101. Table 1
summarizes the facts and holdings of the major cases.

108The Modern Alice/Mayo Framework." 108. Mayo Collaborative Servs. v. Prometheus Labs., Inc., 566 U.S. 66, 71 (2012) (quoting Gottschalk v. Benson, 409 Mayo Collaborative Servs. v. Prometheus Labs., Inc., 566 U.S. 66, 71 (2012) (quoting Gottschalk v. Benson, 409
U.S. 63, 67 (1972)).U.S. 63, 67 (1972)).
109 109. Diamond v. Chakrabarty, 447 U.S. 303, 309 (1980). Diamond v. Chakrabarty, 447 U.S. 303, 309 (1980).
110 110. See, e.g.,, Diehr, 450 U.S. at 187; Funk Bros. Seed Co. v. Kalo Inoculant Co., 333 U.S. 127, 130 (1948); Mackay , 450 U.S. at 187; Funk Bros. Seed Co. v. Kalo Inoculant Co., 333 U.S. 127, 130 (1948); Mackay
Radio & Telegraph Co. v. Radio of Am., 306 U.S. 86, 94 (1939); Radio & Telegraph Co. v. Radio of Am., 306 U.S. 86, 94 (1939); Le Roy, 55 U.S. at 174–75., 55 U.S. at 174–75.
111 111. See Morris, Morris, supra note 106,note 106, at 62 (describing the Supreme Court at 62 (describing the Supreme Court’'s patentable subject matter jurisprudence as s patentable subject matter jurisprudence as
“"insolubly murkyinsolubly murky”"); Klein, ); Klein, supra note 106,note 106, at 289 (describing the three categories of nonpatentable subject matter as at 289 (describing the three categories of nonpatentable subject matter as
“"metaphysically vague and extra-statutorymetaphysically vague and extra-statutory”"); ); Funk Bros., 333 U.S. at 134–35 (Frankfurter, J., concurring) (, 333 U.S. at 134–35 (Frankfurter, J., concurring) (“"It only It only
confuses the issue, however, to introduce such terms as confuses the issue, however, to introduce such terms as ‘'the work of naturethe work of nature’' and the and the ‘'laws of nature.laws of nature.’' For these are For these are
vague and malleable terms infected with too much ambiguity and equivocation. Everything that happens may be vague and malleable terms infected with too much ambiguity and equivocation. Everything that happens may be
deemed deemed ‘'the work of nature,the work of nature,’' and any patentable composite exemplifies in its properties and any patentable composite exemplifies in its properties ‘'the laws of nature.the laws of nature.’”).
112'"). 112. See, e.g., Peter S. Menell, , Peter S. Menell, Forty Years of Wondering in the Wilderness and No Closer to the Promised Land:
BilskiBilski’s's Superficial Textualism and the Missed Opportunity to Return Patent Law to Its Technology Mooring, 63 , 63 STAN.
L. REVStan. L. Rev. 1289, 1307 (2011) (. 1289, 1307 (2011) (“"Since the founding of our nation, courts have evolved [patentable subject matter limits] Since the founding of our nation, courts have evolved [patentable subject matter limits]
within a hybrid constitutional/common law tradition.within a hybrid constitutional/common law tradition.”"); Lemley et al., ); Lemley et al., supra note 21,note 21, at 1325 (describing the three at 1325 (describing the three
judicially created ineligible categories as judicially created ineligible categories as “"common law exceptionscommon law exceptions”" to patentable subject matter). to patentable subject matter).
113 113. The evolving standards applied to the patentability of computer software over the last 50 years are just one notable The evolving standards applied to the patentability of computer software over the last 50 years are just one notable
example. example. See generally Lemley et al., Lemley et al., supra note 21,note 21, at 1317–19 (reviewing the at 1317–19 (reviewing the “"tortured historytortured history”" of the patentability of the patentability
of software). of software). Compare, , e.g., , Benson, 409 U.S. 63 (method for converting binary-coded decimal numerals into pure , 409 U.S. 63 (method for converting binary-coded decimal numerals into pure
binary numerals on computer is not patentable subject matter) binary numerals on computer is not patentable subject matter) with State Street Bank v. Signature Fin. Grp., 149 F.3d State Street Bank v. Signature Fin. Grp., 149 F.3d
1368, 1373 (Fed. Cir. 1998) (Rich, J.) (transformations of data are patentable so long as they produce 1368, 1373 (Fed. Cir. 1998) (Rich, J.) (transformations of data are patentable so long as they produce “"a useful, a useful,
concrete and tangible resultconcrete and tangible result”"), ), abrogated by In re Bilski, 545 F.3d 943, 960 (Fed. Cir. 2008) (en banc) Bilski, 545 F.3d 943, 960 (Fed. Cir. 2008) (en banc) and Alice Corp. Alice Corp.
Pty. v. CLS Bank IntPty. v. CLS Bank Int’'l, 573 U.S. 208, 224–26 (2014) (computer-implemented business method not patentable because l, 573 U.S. 208, 224–26 (2014) (computer-implemented business method not patentable because
it is an abstract idea lacking an it is an abstract idea lacking an “"inventive conceptinventive concept”"). For a broader review of the history of patentable subject matter ). For a broader review of the history of patentable subject matter
jurisprudence, see, e.g., Jeffrey A. Lefstin, jurisprudence, see, e.g., Jeffrey A. Lefstin, Inventive Application: A History, 67 , 67 FLAFla. L. . L. REVRev. 565, 570–645 (2015); . 565, 570–645 (2015);
Max Stul Oppenheimer, Max Stul Oppenheimer, PatentsPatents 101: Patentable Subject Matter and Separation of Powers, 15 , 15 VANDVand. J. . J. ENT. & TECH.
Ent. & Tech. L. 1, 5–28 (2012); Joshua D. Sarnoff, L. 1, 5–28 (2012); Joshua D. Sarnoff, Patent-Eligible Inventions After BilskiBilski: History and Theory, 63 , 63 HASTINGSHastings L.J. L.J.
53, 63–90 (2011); John F. Duffy, 53, 63–90 (2011); John F. Duffy, Rules and Standards on the Forefront of Patentability, 51 , 51 WM. & MARY L. REVWm. & Mary L. Rev. 609, . 609,
623–46 (2009).623–46 (2009).
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Historical Development of the Judicial Exceptions to
Patent-Eligible Subject Matter
Nineteenth Century
The 1853 case of Le Roy v. Tatham, the “fountainhead” of American patentable subject matter
jurisprudence,114 concerned a patent on machinery to manufacture metal pipes that exploited a
newly developed property of lead.115 Although the Court ultimately did not decide the case on
subject matter grounds,116 Le Roy relied on influential English patent cases117 to set forth a basic
distinction between abstract “principles” and natural laws (which may not be patented) and
practical applications of those principles (which may be patented).118 The Court stated that “[a]
principle, in the abstract, is a fundamental truth; an original cause; a motive; these cannot be
patented, as no one can claim in either of them an exclusive right.”119 On the other hand, a “new
property discovered in matter, when practically applied, in the construction of a useful article of
commerce or manufacture, is patentable,” for the “invention is not in discovering [the natural
principles], but in applying them to useful objects.”120
In its next term, the Court applied this rule, in the famous case of O’Reilly v. Morse,121 to Samuel
Morse’s patent on the telegraph. Although the Court found that Morse was the first inventor of
the telegraph and sustained much of his patent,122 the Court rejected Morse’s eighth claim to any
“use of the motive power of the electric or galvanic current . . . however developed for marking
or printing intelligible characters, signs, or letters, at any distances, being a new application of
that power of which I claim to be the first inventor or discoverer.”123 Observing that “the
discovery of a principle in natural philosophy or physical science, is not patentable,”124 Chief
Justice Roger Taney’s majority opinion held that Morse’s eighth claim was “too broad” because
he had not discovered “that the electric or galvanic current will always print at a distance, no
matter what may be the form of the machinery” used, but only that the specific machinery
disclosed in the patent specification would do so.125
In the second half of the nineteenth century, the Court issued a series of important decisions on
the patentability of processes. The result of these cases was a move away from an earlier rule that
prohibited “pure” method patents as ineligible (i.e., a process claimed independently of the

114 114. See infra Table 1. 115. See, e.g., Lefstin, , Lefstin, supra note 113,note 113, at 594 (describing at 594 (describing Le Roy as as “"the fountainhead of subject-matter exclusion in the fountainhead of subject-matter exclusion in
American patent lawAmerican patent law”"); Menell, ); Menell, supra note 112,note 112, at 1296 (describing at 1296 (describing Le Roy as as “"the foundation for much patentable the foundation for much patentable
subject matter jurisprudencesubject matter jurisprudence”).
115"). 116. 55 U.S. (14 How.) 156, 176–77 (1853). 55 U.S. (14 How.) 156, 176–77 (1853).
116 117. The dispositive issue in the case was the scope of the patent claims. The dispositive issue in the case was the scope of the patent claims. See infra note 180; note 181; Lefstin, Lefstin, supra note 113,note 113, at at
595 (595 (“"The outcome in The outcome in Le Roy therefore turned entirely on the Court therefore turned entirely on the Court’'s narrow construction of the claim.s narrow construction of the claim.”).
117"). 118. For a full historical account of these English cases and how they shaped the Supreme Court For a full historical account of these English cases and how they shaped the Supreme Court’'s jurisprudence, see s jurisprudence, see
Lefstin, Lefstin, supra note 113, at 577–644.
118note 113, at 577–644. 119.

Le Roy, 55 U.S. at 174–75.

120.

Id. at 175.

121.

Id.

122.

56 U.S. 62 (1853).

123.

Id. at 111–12, 123–24.

124.

Id. at 112–20.

125.

Id. at 116.

126.

Id. at 117, 119.

127. See, e.g., Corning v. Burden, 56 U.S. (15 How.) 252, 268–70 (1853) (construing "equivocal" Le Roy, 55 U.S. at 174–75.
119 Id. at 175.
120 Id.
121 56 U.S. 62 (1853).
122 Id. at 111–12, 123–24.
123 Id. at 112–20.
124 Id. at 116.
125 Id. at 117, 119.
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specific machinery used to accomplish the method) either by construing nominal process patents
as claiming a machine or limiting the process patents to the machinery disclosed and its
equivalents.126 In Cochrane v. Deener, which involved a patent on an improved manufacturing
process for flour, the Court defined a patentable process as “a mode of treatment of certain
materials to produce a given result. It is an act, or a series of acts, performed upon the subject-
matter to be transformed and reduced to a different state or thing.”127 Cochrane held that such
methods are patentable “irrespective of the particular form of the instrumentalities used.”128
Similarly, in Tilghman v. Proctor, the Court held that a method for separating fat into glycerin and
fatty acids using water, pressure, and heat was patentable.129
In The Telephone Cases, the Court distinguished Morse to allow Alexander Graham Bell’s patent
claim on a “method of and apparatus for transmitting vocal or other sounds telegraphically, as
herein described, by causing electrical undulations, similar in form to the vibrations of the air
accompanying the said vocal or other sounds, substantially as set forth.”130 Chief Justice Edward
Douglass White interpreted Morse as holding that “the use of magnetism as a motive power,
without regard to the particular process with which it was connected in the patent, could not be
claimed, but that its use in that connection could.”131 The Court found that Bell’s claim, unlike
Morse’s, did not reach uses of electricity to transmit speech that are “distinct from the particular
process with which it is connected in [Bell’s] patent,” and upheld the claim, so construed.132
Twentieth Century
In the first half of the 20th century, the Court decided two major cases on the patentability of
natural phenomena. In American Fruit Growers v. Brogdex Co., the Court rejected patent claims
on citrus fruit treated with a solution of borax to render it resistant to mold.133 The Court held that
treated fruit was not a “manufacture” under Section 101, but a patent-ineligible “natural article”;
treatment with borax did not effect a “change in the name, appearance, or general character of the
fruit” or imbue it with a “new or distinctive form, quality, or property.”134 In Funk Brothers Seed
Co. v. Kalo Inoculant Co., the Court rejected patent claims on an inoculant for leguminous plants
consisting of multiple species of bacteria, where the particular bacterial strains were selected to
avoid inhibiting each other (as prior multispecies combinations had).135 Because the patentee’s
combination “produces no new bacteria [and] no change in the six species of bacteria,” Justice

126 See, e.g., Corning v. Burden, 56 U.S. (15 How.) 252, 268–70 (1853) (construing “equivocal” patent to claim a patent to claim a
machine, and not a process, to save its validity because a machine, and not a process, to save its validity because a “process”"process" in the sense of in the sense of “"the function of a machine, or the the function of a machine, or the
effect produced by iteffect produced by it”" cannot be patented); cannot be patented); see generally Sarnoff, Sarnoff, supra note 113, note 113, at 67 (at 67 (“"[A]t the end of the eighteenth [A]t the end of the eighteenth
century, pure method patents—methods claiming all future applications and not merely those substantially similar to century, pure method patents—methods claiming all future applications and not merely those substantially similar to
the disclosed implementing machinery and their equivalents—were ineligible for protection and remained so until the the disclosed implementing machinery and their equivalents—were ineligible for protection and remained so until the
late nineteenth century.late nineteenth century.”") & ) & id. n. 88 (collecting cases).n. 88 (collecting cases).
127 94 U.S. 780, 788 (1876).
128 Id. at 787.
129 128.

94 U.S. 780, 788 (1876).

129.

Id. at 787.

130. 102 U.S. 707, 728–30 (1880). 102 U.S. 707, 728–30 (1880).
130 131.

Dolbear v. Am. Bell Tel. Co. (The Telephone Cases), 126 U.S. 1, 531, 534–35 (1888).

132.

Id. at 534.

133.

Id. at 534–35.

134.

283 U.S. 1, 6, 11–12 (1931).

135.

Id. at 11–12.

136.

333 U.S. 127, 130–32 (1948).

137.

Id.

138. Dolbear v. Am. Bell Tel. Co. (The Telephone Cases), 126 U.S. 1, 531, 534–35 (1888).
131 Id. at 534.
132 Id. at 534–35.
133 283 U.S. 1, 6, 11–12 (1931).
134 Id. at 11–12.
135 333 U.S. 127, 130–32 (1948).
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William Douglas’s majority opinion held that it was only “the discovery of some of the
handiwork of nature and hence is not patentable.”136
From 1972 to 1981, the Supreme Court decided four patentable subject matter cases.137 In
Gottschalk v. Benson, the Court held that an algorithm for converting binary-coded decimal
numerals into pure binary numerals (either by hand, or, more practically, on a computer) was
patent-ineligible.138 Justice Douglas reasoned that “one may not patent an idea” and that
upholding this patent would “wholly pre-empt the mathematical formula and in practical effect
would be a patent on the algorithm itself.”139 Second, in Parker v. Flook, the Court rejected a
patent on a method for updating alarm limits during catalytic conversion of hydrocarbons (such as
petroleum), which relied in part on a mathematical formula, because the only novel feature of the
method was the mathematical formula.140 Third, in Diamond v. Chakrabarty, the Court upheld a
patent on a genetically engineered bacterium useful in breaking down oil (e.g., in cleaning up oil
spills).141 Chief Justice Warren Burger distinguished American Fruit Growers and Funk Brothers
because this bacterium, although a living organism, was human-made and possessed “markedly
different characteristics from any [bacteria] found in nature.”142 Finally, in Diamond v. Diehr, the
Court distinguished Flook to uphold a patent on a process for molding synthetic rubber that relied
on a mathematical formula (the Arrhenius equation).143 Justice William Rehnquist’s majority
opinion reached back to Cochrane v. Deener, holding that the process at issue was patentable
because it transformed an article (uncured rubber) into a different state or thing.144 Even though
the method used a mathematical formula, the patent in Diehr did not claim the formula itself and
would not “pre-empt the use of that equation” in other fields.145
After Diehr, the Court did not decide a major patentable subject matter case for nearly 30
years.146 Development of patent-eligible subject matter law was mainly left to the Federal Circuit,

136 Id.
137 Three of these four ( Three of these four (Benson, , Flook, and , and Diehr), which concern the patentability of inventions relating to ), which concern the patentability of inventions relating to
mathematical formulas and computers, are often referred to as a mathematical formulas and computers, are often referred to as a “"trilogy.trilogy.”" See, e.g., Michel, , Michel, supra note 20,note 20, at 1755; at 1755;
Menell,Menell, supra note 112,note 112, at 1290. This usage leaves out at 1290. This usage leaves out Chakrabarty, which was also decided in the same time frame, , which was also decided in the same time frame,
because that case concerned the exception for products of nature.because that case concerned the exception for products of nature.
138 139. 409 U.S. 63, 64, 71–73 (1972). 409 U.S. 63, 64, 71–73 (1972).
139 Id. at 71–72.
140 140.

Id. at 71–72.

141. 437 U.S. 584, 585, 591–92 (1978). 437 U.S. 584, 585, 591–92 (1978).
141 142. 447 U.S. 303, 305, 309–10 (1980). 447 U.S. 303, 305, 309–10 (1980).
142 Id. at 310.
143 450 U.S. 175, 177, 183–93 (1981).
144 Id. at 184.
145 143.

Id. at 310.

144.

450 U.S. 175, 177, 183–93 (1981).

145.

Id. at 184.

146. Id. at 187. In the view of many commentators, at 187. In the view of many commentators, Diehr effectively overturned effectively overturned Flook (or at least some statements in (or at least some statements in
Flook)) without explicitly saying so. without explicitly saying so. See, e.g., Michel, , Michel, supra note 20,note 20, at 1756 ( at 1756 (“"Diehr, to my eye, overruled , to my eye, overruled Flook five five
to four.to four.”"); Menell,); Menell, supra note 112,note 112, at 1298 ( at 1298 (“"Justice Rehnquist [in Justice Rehnquist [in Diehr] effectively overrode ] effectively overrode Flook’'s statutory subject s statutory subject
matter test.matter test.”"); ); BCLT Report, , supra note 16,note 16, at 554 ( at 554 (“"Flook was effectively overruled three years later in was effectively overruled three years later in Diamond v.
Diehr . . . . . . . .”"); Athena Diagnostics, Inc. v. Mayo Collaborative Servs., 927 F.3d 1333, 1346 (Fed. Cir. 2019) (Chen, J., ); Athena Diagnostics, Inc. v. Mayo Collaborative Servs., 927 F.3d 1333, 1346 (Fed. Cir. 2019) (Chen, J.,
concurring in the denial of rehearing en banc) (concurring in the denial of rehearing en banc) (“"Given Given Diehr’'s evident disagreement with s evident disagreement with Flook’'s analysis, s analysis, Diehr, as , as
the later opinion, was widely understood to be the guiding, settled precedent on § 101 for three decades.the later opinion, was widely understood to be the guiding, settled precedent on § 101 for three decades.”"); Dennis ); Dennis
Crouch, Crouch, Revival of Parker v. Flook Parker v. Flook II, , PATENTLYOPatentlyO (Jan. 4, 2018), https://patentlyo.com/patent/2018/01/revival-parker- (Jan. 4, 2018), https://patentlyo.com/patent/2018/01/revival-parker-
flook.html (presenting data showing that courts rarely cited flook.html (presenting data showing that courts rarely cited Flook between 1982 and 2007). between 1982 and 2007).
The Supreme Court does not appear to view matters this way, however—it continues to cite and rely on The Supreme Court does not appear to view matters this way, however—it continues to cite and rely on Flook as good as good
law. law. See, e.g.,, Alice Corp. Pty. v. CLS Bank IntAlice Corp. Pty. v. CLS Bank Int’'l, 573 U.S. 208, 218, 222 (2014).l, 573 U.S. 208, 218, 222 (2014).
146 147. See Lemley et al., Lemley et al., supra note 21,note 21, at 1317; Menell, at 1317; Menell, supra note 112,note 112, at 1298. There are two partial exceptions to this at 1298. There are two partial exceptions to this
generalization. The first is generalization. The first is J.E.M. Ag SupplySupply, Inc. v. Pioneer Hi-Bred Int’'l, Inc., in which the Court held that human-., in which the Court held that human-
made plant varieties were patentable under Section 101. 534 U.S. 124, 127 (2001). However, that case turned not on
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whose decisions generally expanded patent-eligible subject matter,147 such that by the late 1990s
Section 101 became perceived as “a dead letter.”148
The Modern Alice/Mayo Framework
In 2010, the Supreme Court reentered the field of patent-eligible subject matter, deciding four
cases on the issue within five years.149 These cases established the two-step Alice/Mayo test for
patentable subject matter.
The first step of the Alice/Mayo test addresses whether the patent claims are “directed to” an
ineligible concept: a law of nature, a natural phenomenon, or an abstract idea.150 The inquiry at
step one focuses on the “claim as whole.”151 To be “directed to” an eligible concept at step one of
Alice/Mayo, the claims must not simply involve a patent-ineligible concept.152 Rather, the “focus
on the claims” must be a patent-ineligible concept, and not the improvement of a technological
process.153 If the patent claims are not directed to an ineligible concept, then the subject matter is
patent-eligible.154
If the claims are directed to an ineligible category, then the invention is not patentable unless the
patent claims have an “inventive concept” under the second step of the Alice/Mayo test.155 Step
two of Alice/Mayo considers the elements of each patent claim both individually and as an
ordered combination in the search for an “inventive concept”—additional elements that
“transform the nature of the claim” into a patent-eligible application of an ineligible concept.156
To have an “inventive concept,” the patent claims must contain elements “sufficient to ensure that

made plant varieties were patentable under Section 101. 534 U.S. 124, 127 (2001). However, that case turned not on general patent-eligibility principles, but on whether two specialized statutes for protection of plant varieties precluded general patent-eligibility principles, but on whether two specialized statutes for protection of plant varieties precluded
utility patents on plants under the general provisions of Section 101. utility patents on plants under the general provisions of Section 101. Id. at 132–44. Second, although the Supreme at 132–44. Second, although the Supreme
Court ultimately did not decide the case, Justice BreyerCourt ultimately did not decide the case, Justice Breyer’'s 2006 dissent from the dismissal of a writ of certiorari as s 2006 dissent from the dismissal of a writ of certiorari as
improvidently granted in improvidently granted in Laboratory Corporation of America Holdings v. Metabolite Laboratories, Inc., served as an , served as an
important signal of the Courtimportant signal of the Court’'s renewed interest in patentable subject matter. s renewed interest in patentable subject matter. See 548 U.S. 124 (2006). 548 U.S. 124 (2006). Metabolite
involved claims for diagnosing vitamin deficiencies, much like the claims the Supreme Court would address years later involved claims for diagnosing vitamin deficiencies, much like the claims the Supreme Court would address years later
in in Mayo, when the Court largely adopted the reasoning of Justice Breyer, when the Court largely adopted the reasoning of Justice Breyer’'s s Metabolite dissent. dissent. See id. at 129, 135–38. at 129, 135–38.
147 148. See generally Menell, Menell, supra note 112,note 112, at 1298–99; Julie E. Cohen & Mark A. Lemley, at 1298–99; Julie E. Cohen & Mark A. Lemley, Patent Scope and Innovation
in the Software Industry, 89 , 89 CALCal. L. . L. REVRev. 1, 9–14 (2001). The canonical examples are . 1, 9–14 (2001). The canonical examples are In re Alappat, 33 F.3d 1526, , 33 F.3d 1526,
1542–45 (Fed. Cir. 1994) (en banc) (permitting software claims if tied to a machine, including a programmed general1542–45 (Fed. Cir. 1994) (en banc) (permitting software claims if tied to a machine, including a programmed general
-purpose computer) and purpose computer) and State Street Bank v. Signature Financial Group, 149 F.3d 1368, 1373 (Fed. Cir. 1998) (Rich, J.) , 149 F.3d 1368, 1373 (Fed. Cir. 1998) (Rich, J.)
(holding that computer-implemented business methods are patentable if tied to a machine that produces (holding that computer-implemented business methods are patentable if tied to a machine that produces “"a useful, a useful,
concrete and tangible resultconcrete and tangible result”"). Both cases were later abrogated. ). Both cases were later abrogated. See In re Bilski, 545 F.3d 943, 959–60 (Fed. Cir. 2008) Bilski, 545 F.3d 943, 959–60 (Fed. Cir. 2008)
(en banc), (en banc), aff’'d, sub nom. Bilski v. Kappos, 561 U.S. 593 (2010).Bilski v. Kappos, 561 U.S. 593 (2010).
148 149. Lemley et al., Lemley et al., supra note 21,note 21, at 1318 ( at 1318 (“"[A]fter 1998, patentable subject matter was effectively a dead letter[A]fter 1998, patentable subject matter was effectively a dead letter”"). 150. ).
149 Bilski v. Kappos, 561 U.S. 593 (2010); Mayo Collaborative Servs. v. Prometheus Labs., Inc., 566 U.S. 66 (2012); Bilski v. Kappos, 561 U.S. 593 (2010); Mayo Collaborative Servs. v. Prometheus Labs., Inc., 566 U.S. 66 (2012);
Ass’Ass'n for Molecular Pathology v. Myriad Genetics, Inc., 569 U.S. 576 (2013); Alice Corp. Pty. v. CLS Bank Intn for Molecular Pathology v. Myriad Genetics, Inc., 569 U.S. 576 (2013); Alice Corp. Pty. v. CLS Bank Int’'l, 573 l, 573
U.S. 208 (2014).U.S. 208 (2014).
150 Alice, 573 U.S. at 217.
151 151.

Alice, 573 U.S. at 217.

152. Athena Diagnostics, Inc. v. Mayo Collaborative Servs., 915 F.3d 743, 750 (Fed. Cir. 2019) (citing Elec. Power Grp., Athena Diagnostics, Inc. v. Mayo Collaborative Servs., 915 F.3d 743, 750 (Fed. Cir. 2019) (citing Elec. Power Grp.,
v. Alstom S.A., 830 F.3d 1350, 1353 (Fed. Cir. 2016)).v. Alstom S.A., 830 F.3d 1350, 1353 (Fed. Cir. 2016)).
152 153. Enfish, LLC v. Microsoft Corp., 822 F.3d 1327, 1335–36 (Fed. Cir. 2016). Enfish, LLC v. Microsoft Corp., 822 F.3d 1327, 1335–36 (Fed. Cir. 2016).
153 154. Id.; ; see also Athena, 915 F.3d at 750 (, 915 F.3d at 750 (“"To determine whether a claim is directed to an ineligible concept, we have To determine whether a claim is directed to an ineligible concept, we have
frequently considered whether the claimed advance improves upon a technological process or merely an ineligible frequently considered whether the claimed advance improves upon a technological process or merely an ineligible
concept, based on both the written description and the claim.concept, based on both the written description and the claim.”") (citations omitted). 155.

Alice, 573 U.S. at 217.

156.

Id.

157.

Alice, 573 U.S. at 217–28 (quotations omitted).

158.

Id. (quoting Mayo Collaborative Servs. v. Prometheus Labs., Inc., 566 U.S. 66, 73 (2012)).

159. ) (citations omitted).
154 Alice, 573 U.S. at 217.
155 Id.
156 Alice, 573 U.S. at 217–28 (quotations omitted).
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the patent in practice amounts to significantly more than a patent upon the [ineligible concept]
itself.”157 Claim limitations that are “conventional, routine and well understood,” such as generic
computer implementation, cannot supply an inventive concept.158
Bilski v. Kappos, the first in the series of Supreme Court cases that developed what became
known as the Alice/Mayo framework, concerned a patent on a business method for hedging
against price-fluctuation risks in energy and commodity markets.159 The Federal Circuit had held
that this method was not patentable as a “process” under Section 101 because it failed the
“machine-or-transformation test”—that is, it was neither “tied to a particular machine or
apparatus” nor “transform[ed] a particular article into a different state or thing.”160 All nine
members of the Supreme Court agreed with that result—that the business method at issue was not
patent-eligible—but differed significantly as to their reasoning. Writing for five Justices, Justice
Anthony Kennedy held that the machine-or-transformation test was not the “sole test” for
determining whether a process is patent-eligible but still “a useful and important clue.”161 While
the majority rejected the “atextual” notion that business methods were categorically unpatentable
under Section 101,162 it relied on Benson and Flook to conclude that this particular patent
attempted to claim an unpatentable abstract idea: the “concept of hedging risk.”163 Concurring
only in the judgment, Justice John Paul Stevens wrote for four Justices who would have held,
based on the history of the Patent Act and its constitutional purpose, that business methods were
always patent-ineligible.164
In Mayo Collaborative Services v. Prometheus Laboratories, the Court addressed the scope of the
“law of nature” exception.165 The patent in Mayo claimed a method for measuring metabolites in
human blood in order to calibrate the dosage of thiopurine drugs in the treatment of autoimmune
disorders.166 Writing for a unanimous Court, Justice Stephen Breyer’s opinion held that the patent
claims were addressed to a law of nature: “namely, relationships between concentrations of
certain metabolites in the blood and the likelihood that a dosage of a thiopurine drug will prove
ineffective or cause harm.”167 Because the claims were little “more than an instruction to doctors
to apply the applicable laws when treating their patients,” the patent lacked any inventive concept
and was held to be patent-ineligible.168
The next case, Association for Molecular Pathology v. Myriad Genetics, Inc., concerned the
applicability of the “natural phenomena” exception to the patentability of human DNA.169 The

157 Id. (quoting Mayo Collaborative Servs. v. Prometheus Labs., Inc., 566 U.S. 66, 73 (2012)).
158 Ariosa Diagnostics, Inc. v. Sequenom, Inc., 788 F.3d 1371, 1378 (Fed. Cir. 2015); Ariosa Diagnostics, Inc. v. Sequenom, Inc., 788 F.3d 1371, 1378 (Fed. Cir. 2015); accord Alice, 573 U.S. at 225; , 573 U.S. at 225;
Mayo, 566 U.S. at 79 (, 566 U.S. at 79 (“"Purely Purely ‘'conventional or obviousconventional or obvious’ ‘' '[pre]-solution activity[pre]-solution activity’' is normally not sufficient to transform is normally not sufficient to transform
an unpatentable law of nature into a patent-eligible application of such a law.an unpatentable law of nature into a patent-eligible application of such a law.”" (quoting Parker v. Flook, 437 U.S. 584, (quoting Parker v. Flook, 437 U.S. 584,
590 (1978))).590 (1978))).
159 160. Bilski, 561 U.S. at 598–99., 561 U.S. at 598–99.
160 161. In re Bilski, 545 F.3d 943, 954 (Fed. Cir. 2008) (en banc) (Michel, C.J.). Bilski, 545 F.3d 943, 954 (Fed. Cir. 2008) (en banc) (Michel, C.J.).
161 Bilski, 561 U.S. at 604.
162 Id. at 609.
163 Id. at 609–12.
164 Id. at 626–57 (Stevens, J., concurring in the judgment).
165 566 U.S. 66, 77 (2012).
166 Id. at 73–75.
167 Id. at 77.
168 Id. at 79.
169 569 U.S. 576 (2013).
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inventor in Myriad had discovered the precise location and genetic sequence of two human genes
associated with an increased risk of breast cancer.170 Based on this discovery, the patentee claimed
two molecules associated with the genes: (1) an isolated DNA segment and (2) a complementary
DNA (cDNA) segment, in which the nucleotide sequences that do not code for amino acids were
removed in the laboratory.171 Justice Clarence Thomas’s unanimous opinion in Myriad held that
isolated DNA segments were nonpatentable products of nature because the patent claimed
naturally occurring genetic information.172 The Court held, however, that cDNA, as a synthetic
molecule distinct from naturally occurring DNA, was patentable even though the underlying
nucleotide sequence was dictated by nature.173
Most recently, Alice Corp. v. CLS Bank International examined the scope of the “abstract idea”
category of nonpatentable subject matter.174 Alice concerned a patent on a system for mitigating
“settlement risk”—the risk that only one party to a financial transaction will pay what it owes—
using a computer as an intermediary.175 The Court first held, relying on Bilski, that the invention
was directed at “the abstract idea of intermediated settlement.”176 Although this idea was
implemented on a computer (which is, of course, a physical machine), the patent lacked an
inventive concept because the claims merely “implement[ed] the abstract idea of intermediated
settlement on a generic computer.”177
Table 1 summarizes the facts and holding of the Supreme Court’s major patentable subject matter
cases, in reverse chronological order.
Table 1. Major Supreme Court Decisions on Patentable Subject Matter
Case Citation
Claimed Inventions
Holding and Rationale
Alice Corp. Pty. v. CLS
Computer-implemented method and
Ineligible: The claims are drawn to the
Bank Int'l, 573 U.S.
system for mitigating settlement risk in
abstract idea of intermediated settlement;
208 (2014)
financial transactions using a third-party
implementation on a generic computer does
intermediary
not transform an ineligible abstract idea into a
patent-eligible invention.
Ass'n for Molecular
Isolated human DNA segments and
Certain Claims Ineligible: Isolated human
Pathology v. Myriad
exon-only complementary DNA (cDNA) DNA segments are patent-ineligible because
Genetics, Inc., 569
segments corresponding to genes
the nucleotide sequence is a product of
U.S. 576 (2013)
discovered to be linked to an increased
nature and isolation from the rest of the
risk of breast cancer
genome is insufficient to render them
patentable; however, cDNA is patentable
because it is not naturally occurring.

170 Id. at 579.
171 Id. at 580–85.
172 Id. at 591–94. Justice Antonin Scalia joined the opinion save for the “fine details of molecular biology,” 162.

Bilski, 561 U.S. at 604.

163.

Id. at 609.

164.

Id. at 609–12.

165.

Id. at 626–57 (Stevens, J., concurring in the judgment).

166.

566 U.S. 66, 77 (2012).

167.

Id. at 73–75.

168.

Id. at 77.

169.

Id. at 79.

170.

569 U.S. 576 (2013).

171.

Id. at 579.

172.

Id. at 580–85.

173. Id. at 591–94. Justice Antonin Scalia joined the opinion save for the "fine details of molecular biology," as he found as he found
himself himself “"unable to affirm those details on my own knowledge or even my own belief.unable to affirm those details on my own knowledge or even my own belief.”" Id. at 596 (Scalia, J., concurring at 596 (Scalia, J., concurring
in part and in the judgment).in part and in the judgment).
173 Id. at 594–95.
174 573 U.S. 208 (2014).
175 Id. at 212.
176 Id. at 221.
177 Id. at 225.
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Case Citation
Claimed Inventions
Holding and Rationale
Mayo Collaborative
Method for optimizing dosage of
Ineligible: The relationship between the
Servs. v. Prometheus
thiopurine drugs for treating
concentration of particular metabolites in the
Labs., Inc., 566 U.S.
autoimmune disease, by administering
blood and a drug’s effectiveness is directed to
66 (2012)
the drug, measuring a metabolite, and
a law of nature, and the claims lack an
adjusting the dosage based on the
inventive concept beyond conventional post-
measurement
solution activity.
Bilski v. Kappos, 561
Business method for hedging against
Ineligible: Although business methods are
U.S. 593 (2010)
price-fluctuation risks in energy and
not categorically patent-ineligible, the process
commodity markets
at issue was not patentable because it claimed
the abstract idea of hedging risk.
J.E.M. Ag. Supply v.
Human-developed inbred and hybrid
Eligible: Newly developed plant varieties are
Pioneer Hi-Bred Int’l,
corn plant varieties and seeds
human-made manufactures or compositions
Inc., 534 U.S. 124
of matter, even though protection may also
(2001)
be available under the Plant Patent Act or the
Plant Variety Protection Act.
Diamond v. Diehr, 450 Process for molding raw, uncured
Eligible: The invention does not claim a
U.S. 175 (1981)
synthetic rubber into cured products,
mathematical formula or a law of nature as
relying on the Arrhenius equation and a
such, but applies a natural law to a particular
programmed computer to calculate the
industrial process that transforms an article
curing time
into a different state or thing.
Diamond v.
Genetically engineered bacterium
Eligible: The genetically engineered
Chakrabarty, 447 U.S.
capable of breaking down components in bacterium was not naturally occurring and
303 (1980)
crude oil
possessed markedly different characteristics
from any bacteria found in nature.
Parker v. Flook, 437
Method of updating alarm limits used in
Ineligible: The only novel feature of the
U.S. 584 (1978)
catalytic conversion of hydrocarbons
invention was a mathematical formula,
(e.g., in oil refining) relying on a
conventionally applied to a specific field.
mathematical formula
Gottschalk v. Benson,
Method for converting binary-coded
Ineligible: The patent claims cover all
409 U.S. 63 (1972)
decimal numerals into pure binary
practical uses of a mathematical algorithm and
numerals on digital computer
would, in effect, amount to a patent on the
algorithm itself.
Funk Bros. Seed Co. v.
Inoculant for leguminous plants
Ineligible: Each bacterial strain is naturally
Kalo Inoculant Co.,
comprising several strains of mutually
occurring, and discovery of the noninhibitive
333 U.S. 127 (1948)
noninhibitive species of bacteria to
qualities of certain strains was not invention
improve nitrogen fixation
but merely the discovery of a nonpatentable
natural phenomenon.
Mackay Radio & Tel.
Radio antenna in which the angle of the
Assumed to be patentable: Although a
Co. v. Radio Corp. of
wires and their length are determined by mathematical expression of a scientific truth
Am., 306 U.S. 86
a mathematical formula
is not patentable, a novel and useful structure
(1939)178
created with the aid of knowledge of scientific
truth may be patentable.
Am. Fruit Growers v.
Citrus fruit treated with borax solution
Ineligible: Treatment with borax did not
Brogdex Co., 283 U.S.
to render it resistant to mold
transform the fruit (a product of nature) into
1 (1931)
a manufacture with a new or distinctive form,
quality, or property.

178 174.

Id. at 594–95.

175.

573 U.S. 208 (2014).

176.

Id. at 212.

177.

Id. at 221.

178.

Id. at 225.

179. Although Although Mackay Radio is widely quoted in subsequent jurisprudence for the proposition that useful applications of is widely quoted in subsequent jurisprudence for the proposition that useful applications of
laws of nature are patentable, see, for example,laws of nature are patentable, see, for example, Mayo Collaborative Servs. v. Prometheus Labs., Inc., 566 U.S. 66, 71 Mayo Collaborative Servs. v. Prometheus Labs., Inc., 566 U.S. 66, 71
(2012); Diamond v. Diehr, 450 U.S. 175, 188 (1981), Justice Harlan Stone(2012); Diamond v. Diehr, 450 U.S. 175, 188 (1981), Justice Harlan Stone’'s statement is dicta because the Court s statement is dicta because the Court
merely merely “"assume[d], without decidingassume[d], without deciding”" that the invention was patentable, ruling instead on grounds of noninfringement, that the invention was patentable, ruling instead on grounds of noninfringement,
see see Mackay Radio,, 306 U.S. at 94, 101.306 U.S. at 94, 101.
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Case Citation
Claimed Inventions
Holding and Rationale
The Telephone Cases,
Method and apparatus for transmitting
Eligible: The patentee did not claim all uses
126 U.S. 1 (1888)
sound telegraphically by causing
of electricity to transmit speech at a distance,
electrical undulations, similar to air
but only the particular process and apparatus
vibrations accompanying speech and
disclosed in the patent.
other sounds
Tilghman v. Proctor,
Process for separating fat into glycerin
Eligible: New and useful manufacturing
102 U.S. 707 (1881)
and fatty acids using water, pressure, and processes are “arts” that may be patented
heat
independently of the apparatus used.
Cochrane v. Deener,
Improved industrial process for
Eligible: A process (“a series of acts,
94 U.S. 780 (1877)
manufacturing flour
performed upon the subject-matter to be
transformed and reduced to a different state
or thing”) is patentable independent of the
machinery used.
Rubber-Tip Pencil Co.
Rubber cap with cavity designed to be
Ineligible: An “idea of itself” (here, the idea
v. Howard, 87 U.S.
attached to lead pencils for convenient
of attaching a piece of rubber to the end of a
(20 Wall.) 498
use as an eraser
pencil for use as an eraser) is not patentable.
(1874)
Corning v. Burden, 56
Machine for rol ing puddle balls and
Eligible: The patentee did not claim the
U.S. (15 How.) 252
other masses of iron used in the
function or abstract effect of a machine, but
(1854)
manufacture of iron products
only the machine that produced the result.
O'Reilly v. Morse, 56
Any use of electro-magnetism for
Ineligible: The discovery of a scientific
U.S. (15 How.) 62
printing intelligible characters, signs, or
principle is not patentable, nor can a patentee
(1854)179
letters, at a distance
claim a useful result in the abstract, apart
from the particular process or machine by
which the result is accomplished.
Le Roy v. Tatham, 55
Machinery for manufacturing wrought
Potentially patentable: Although a
U.S. (14 How.) 156
metal pipes exploiting a newly
principle in the abstract is not patentable, a
(1853)180
discovered property of lead
practical application of such a principle to a
new and useful end is patentable.
Source: CRS.

179 180. The specific doctrinal basis of The specific doctrinal basis of O’'Reilly v. Morse is unclear, as the Court speaks in language that, when cast in is unclear, as the Court speaks in language that, when cast in
modern terms, sounds at times like enablement and at times like patentable subject matter. modern terms, sounds at times like enablement and at times like patentable subject matter. Compare 56 U.S. at 113 56 U.S. at 113
(“("The court is of opinion that the claim is too broad . . . .The court is of opinion that the claim is too broad . . . .”") ) with id. at 116 ( at 116 (“"[T]he discovery of a principle in natural [T]he discovery of a principle in natural
philosophy or physical science, is not patentable.philosophy or physical science, is not patentable.”"). Many patent scholars regard ). Many patent scholars regard Morse as a case not about Section 101 as a case not about Section 101
but about enablement under Section 112 of the modern Patent Act. but about enablement under Section 112 of the modern Patent Act. See, e.g., Taylor, , Taylor, supra note 20, note 20, at 205 (at 205 (“"In modern In modern
terms, it is quite clear that the problem with Claim 8 in terms, it is quite clear that the problem with Claim 8 in Morse’'s patent was based on the enablement and written s patent was based on the enablement and written
description requirements located in § 112 and not in § 101.description requirements located in § 112 and not in § 101.”"); Lefstin, ); Lefstin, supra note 113,note 113, at 597 ( at 597 (“"Morse is about is about
disclosure and scope, not patent-eligible subject matter.disclosure and scope, not patent-eligible subject matter.”"). The Supreme Court, however, appears to regard ). The Supreme Court, however, appears to regard Morse as as
primarily a subject matter decision. primarily a subject matter decision. See, e.g., , Mayo, 566 U.S. at 70, 73 (citing to , 566 U.S. at 70, 73 (citing to Morse to support notion that to support notion that “"laws of laws of
nature”nature" or claims that or claims that “"preempt the use of a natural lawpreempt the use of a natural law”" are are “"not patentablenot patentable”).
180"). 181. Statements in Statements in Le Roy to the effect that a to the effect that a “"principle, in the abstractprinciple, in the abstract”" is not patentable, but a practical application of is not patentable, but a practical application of
such a principle may be patentable, 55 U.S. at 174–75, are widely quoted and influential in subsequent American such a principle may be patentable, 55 U.S. at 174–75, are widely quoted and influential in subsequent American
jurisprudence. jurisprudence. See supra note 114.note 115. Nonetheless, because the result in Nonetheless, because the result in Le Roy turned primarily on claim construction, turned primarily on claim construction,
see 55 U.S. at 176, these general statements were dicta and did not entail the holding of the case.55 U.S. at 176, these general statements were dicta and did not entail the holding of the case.
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The Debate Over Alice/Mayo and Section 101
Reform
A substantial group of patent law stakeholders, including inventors, academics, industry
representatives, patent attorneys, current and former Federal Circuit judges, and former PTO
officials, has criticized the Alice/Mayo framework on various grounds.181 Other patent law
stakeholders defend the Supreme Court’s Section 101 decisions.182
Criticisms of the Alice/Mayo Framework
Generally, critics of the Court’s patentable subject matter jurisprudence raise four principal
concerns. First, the Alice/Mayo framework is criticized as excessively vague, subjective, and
unpredictable in application. For example, the Federal Circuit has stated that when determining
whether a patent claim is “directed to” an ineligible concept at step one, courts must determine
whether the “focus” of the claims is on that concept.183 At the same time, the Federal Circuit has
cautioned that this “focus” must be articulated “with enough specificity to ensure the step one
inquiry is meaningful.”184 The appropriate level of specificity can vary from patent to patent and
from judge to judge.185
Thus, in the view of many stakeholders, the Supreme Court’s patentable subject matter case law
and the Federal Circuit’s implementation of the Alice/Mayo framework fail to articulate
“objective, predictable criteria” for making patent-eligibility determinations.186 Key terms, such
as what an “abstract idea” is, or precisely how claim elements can make an invention
“significantly more” than an ineligible category (the “inventive concept”), are largely left
undefined, making it difficult for patent applicants and litigants to know whether their patent
claims will survive judicial scrutiny.187 Moreover, the Federal Circuit has explicitly recognized

181 182.

See infra "Criticisms of the Alice/Mayo Framework."

183. See infra "Defenses See infra “Criticisms of the Alice/Mayo Framework." 184. Alice/Mayo Framework.”
182 See infra “Defenses of the Alice/Mayo Framework.”
183 Elec. Power Grp. v. Alstom S.A., 830 F.3d 1350, 1353 (Fed. Cir. 2016). Elec. Power Grp. v. Alstom S.A., 830 F.3d 1350, 1353 (Fed. Cir. 2016).
184 185. Thales Visionix Inc. v. United States, 850 F.3d 1343, 1347 (Fed. Cir. 2017). Thales Visionix Inc. v. United States, 850 F.3d 1343, 1347 (Fed. Cir. 2017).
185 186. See Visual Memory LLC v. NVIDIA Corp., 867 F.3d 1253, 1262 (Fed. Cir. 2017) (Hughes, J., dissenting) Visual Memory LLC v. NVIDIA Corp., 867 F.3d 1253, 1262 (Fed. Cir. 2017) (Hughes, J., dissenting)
(disagreeing with the majority over whether characterizing the claims as directed to (disagreeing with the majority over whether characterizing the claims as directed to “"categorical data storagecategorical data storage”" views views
the invention the invention “"at an unduly at an unduly ‘'high level of abstractionhigh level of abstraction’”'") (quoting Enfish, LLC v. Microsoft Corp., 822 F.3d 1327, 1337 ) (quoting Enfish, LLC v. Microsoft Corp., 822 F.3d 1327, 1337
(Fed. Cir. 2016)).(Fed. Cir. 2016)).
186 PTO PSM REPORT, supra note 16, at 29.
187 See 187.

USPTO PSM Report, supra note 16, at 29.

188. See id. at 30 (describing comments that the . at 30 (describing comments that the Alice//Mayo test test “"fails to define crucial terms, such as fails to define crucial terms, such as ‘abstract’'abstract' and ' and
‘substantially moresubstantially more’”'"); Taylor, ); Taylor, supra note 20,note 20, at 231 ( at 231 (“"[N]o one really knows what an inventive concept is.[N]o one really knows what an inventive concept is.”"); Lemley ); Lemley
et al., et al., supra note 21, note 21, at 1316 (at 1316 (“"[N]o one understands what makes an idea [N]o one understands what makes an idea ‘'abstract,abstract,’' and hence ineligible . . . . and hence ineligible . . . .”"); );
Morris, Morris, supra note 106, note 106, at 68 (arguing that the judicially created patentable subject matter decisions are at 68 (arguing that the judicially created patentable subject matter decisions are “"merely post merely post
hoc rationalizationshoc rationalizations”"). Some Supreme Court Justices have echoed this criticism. ). Some Supreme Court Justices have echoed this criticism. See, e.g., Bilski v. Kappos, 561 U.S. , Bilski v. Kappos, 561 U.S.
593, 621 (2010) (Stevens, J., concurring in the judgment) (593, 621 (2010) (Stevens, J., concurring in the judgment) (“"The Court . . . never provides a satisfying account of what The Court . . . never provides a satisfying account of what
constitutes an unpatentable abstract idea.constitutes an unpatentable abstract idea.”"); Fred Funk Seed Bros. Co. v. Kalo Inoculant Co., 333 U.S. 127, 134–35 ); Fred Funk Seed Bros. Co. v. Kalo Inoculant Co., 333 U.S. 127, 134–35
(1948) (Frankfurter, J., concurring) ((1948) (Frankfurter, J., concurring) (“"It only confuses the issue, however, to introduce such terms as It only confuses the issue, however, to introduce such terms as ‘'the work of the work of
nature’nature' and the and the ‘'laws of nature.laws of nature.’' For these are vague and malleable terms infected with too much ambiguity and For these are vague and malleable terms infected with too much ambiguity and
equivocation.equivocation.”"). To some extent, uncertainty in Section 101 is not a new phenomenon.). To some extent, uncertainty in Section 101 is not a new phenomenon. See, e.g., Duffy, , Duffy, supra note 113,
note 113, at 623–38 (reviewing history of failed patentable subject matter rules and observing that at 623–38 (reviewing history of failed patentable subject matter rules and observing that “"instability in the law of instability in the law of
patentable subject matterpatentable subject matter”" is a recurring issue). is a recurring issue). However, at least in the decade before However, at least in the decade before Mayo, uncertainty was less , uncertainty was less
practically important for patentees because courts and the practically important for patentees because courts and the PTO only “rarely”USPTO only "rarely" rejected patents based on Section 101. rejected patents based on Section 101. See
BCLT Report, , supra note 16,note 16, at 575–76 (reviewing data showing a at 575–76 (reviewing data showing a “dramatic”"dramatic" increase in the number of Section 101 increase in the number of Section 101
district court decisions following district court decisions following Mayo, with a , with a “"10-fold10-fold”" increase following increase following Alice).).
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that the two steps of the analysis are not clearly defined and may overlap.188 As a result, many
observers characterize the court’s Section 101 jurisprudence as a “highly subjective,” “I know it
when I see it” approach.189 This subjectivity, in the view of critics, injects unpredictability and
uncertainty into whether an invention is of a type that is patentable.190
Second, the Alice/Mayo framework is criticized as legally flawed on various grounds. Some
stakeholders argue that the Alice/Mayo framework misinterprets Section 101, imposing “extra-
statutory” requirements for patent eligibility, contrary to congressional intent or the constitutional
purpose of patent law.191 Others argue that Mayo’s requirement of an “inventive concept” rests on
a historically inaccurate understanding of 19th century English patent law, first imported into
American jurisprudence in cases such as Le Roy and Morse.192 Finally, many commentators and
stakeholders argue that the Alice/Mayo framework confuses patent law by conflating eligibility
under Section 101 with policy concerns—such as the obviousness of the invention and claim
breadth—that are better addressed by other provisions in the Patent Act, such as Sections 102,
103, and 112.193 For example, patent claims have been found to lack an inventive concept at
Alice/Mayo step two where they implement an abstract idea on conventional computer
hardware.194 Issues about what was “conventional” or “well-understood” at the time of the
invention, however, are questions usually reserved for novelty or nonobviousness analysis.195
Third, the Alice/Mayo framework is alleged to have detrimental effects on incentives to innovate,
especially in the biotechnology and computer software industries. Given the patent claims at issue
in Alice (a computer-implemented business method), Myriad (an isolated human DNA segment),
and Mayo (a drug dose optimization method), most observers agree that these two industries have

188 189. Elec. Power Grp., 830 F.3d at 1353 (, 830 F.3d at 1353 (“"[T]he two stages are plainly related: not only do many of our opinions make [T]he two stages are plainly related: not only do many of our opinions make
clear that the two stages involve overlapping scrutiny of the content of the claims, but we have noted that there can be clear that the two stages involve overlapping scrutiny of the content of the claims, but we have noted that there can be
close questions about when the inquiry should proceed from the first stage to the second.close questions about when the inquiry should proceed from the first stage to the second.”") (citations omitted).) (citations omitted).
189 190. See, e.g., , PTO PSM REPORTUSPTO PSM Report, , supra note 16,note 16, at 30 (quoting stakeholder view that at 30 (quoting stakeholder view that Alice//Mayo is is “"hopelessly hopelessly
subjective”subjective"); Taylor, ); Taylor, supra note 20,note 20, at 227–30 (arguing that at 227–30 (arguing that AliceAlice//Mayo framework has framework has “"no objective guidanceno objective guidance”" and and
“"leaves the determination of eligibility to the unconstrained, subjective opinion of a patent examiner or judgeleaves the determination of eligibility to the unconstrained, subjective opinion of a patent examiner or judge”"); Klein, ); Klein,
supra note 106,note 106, at 288 (criticizing patentable subject matter case law as amounting to at 288 (criticizing patentable subject matter case law as amounting to “"an an ‘'I know it when I see itI know it when I see it’
approach”).
190' approach"). 191. See, e.g., , BCLT Report, , supra note 16,note 16, at 561 (describing at 561 (describing “"uncertainty and confusion resulting from the Courtuncertainty and confusion resulting from the Court’s
's recent [patentable subject matter] jurisprudencerecent [patentable subject matter] jurisprudence”"); ); accord PTO PSM REPORTUSPTO PSM Report, , supra note 16,note 16, at 30–31 (describing at 30–31 (describing
views that the views that the Alice//Mayo test yields test yields “unpredictable” and “inconsistent” results).
191 See PTO PSM REPORT"unpredictable" and "inconsistent" results). 192. See USPTO PSM Report, supra note 16,, supra note 16, at 28; Klein, at 28; Klein, supra note 106, note 106, at 289–91 (criticizing the three judicially at 289–91 (criticizing the three judicially
created categorical exclusions as created categorical exclusions as “"extra-statutoryextra-statutory”" and proposing test that focuses on text of Section 101). and proposing test that focuses on text of Section 101).
192 193. Lefstin, Lefstin, supra note 113,note 113, at 565 (arguing that at 565 (arguing that Alice//Mayo test test’s “'s "inventive applicationinventive application”" requirement rests on a requirement rests on a “"basic misapprehension"basic
misapprehension” of the 19th century English case cited by the Supreme Court); of the 19th century English case cited by the Supreme Court); PTO PSM REPORTUSPTO PSM Report, , supra note 16, at
note 16, at 27–28 (same).27–28 (same).
193 See PTO PSM REPORT 194. See USPTO PSM Report, supra note 16,, supra note 16, at 31–32; Taylor at 31–32; Taylor, supra note 20,note 20, at 157 ( at 157 (“"[T]he current approach to [T]he current approach to
determining patent eligibility confuses the relevant policy concerns underlying numerous discrete patent law determining patent eligibility confuses the relevant policy concerns underlying numerous discrete patent law
doctrines.doctrines.”"); ); see also Risch, Risch, supra note 21,note 21, at 594 (arguing that the Court at 594 (arguing that the Court’'s patentable subject matter doctrine would be s patentable subject matter doctrine would be
more consistent and rigorous if replaced with a strict application of other patentability doctrines such as obviousness, more consistent and rigorous if replaced with a strict application of other patentability doctrines such as obviousness,
novelty, utility, inventorship, written description, and enablement). This criticism has been echoed by Supreme Court novelty, utility, inventorship, written description, and enablement). This criticism has been echoed by Supreme Court
Justices. Justices. See Parker v. Flook, 437 U.S. 584, 600 (1978) (Stewart, J., dissenting) (Parker v. Flook, 437 U.S. 584, 600 (1978) (Stewart, J., dissenting) (“"[The majority] strikes what seems to [The majority] strikes what seems to
me an equally damaging blow at basic principles of patent law by importing into its inquiry under 35 U.S.C. § 101 the me an equally damaging blow at basic principles of patent law by importing into its inquiry under 35 U.S.C. § 101 the
criteria of novelty and inventiveness.criteria of novelty and inventiveness.”).
194"). 195. See, e.g., , Elec. Power Grp., 830 F.3d at 1355., 830 F.3d at 1355.
195 196. See, e.g.,, Berkheimer v. HP Inc., 881 F.3d 1360, 1368–69 (Fed. Cir. 2018) (noting that Berkheimer v. HP Inc., 881 F.3d 1360, 1368–69 (Fed. Cir. 2018) (noting that Alice//Mayo step two step two
determination of whether claims are determination of whether claims are “"well-understood, routine and conventionalwell-understood, routine and conventional”" overlaps with Section 102 novelty overlaps with Section 102 novelty
inquiry).inquiry).
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been the most affected by the Supreme Court’s Section 101 rulings.196 In the biotechnology
industry, stakeholders argue that the Alice/Mayo framework has limited their ability to obtain
patents on diagnostic methods and kits, personalized medicine, and isolated natural substances.197
Views in the computer industry are “sharply divided,” but at least some stakeholders argue that
Alice has devalued their patents and created uncertainty for their business.198 In both fields, some
stakeholders argue that the law of Section 101 is reducing incentives to innovate in these areas
and driving investment elsewhere.199
Finally, the uncertainty and unpredictability caused by Alice/Mayo is alleged to put the United
States at a disadvantage relative to international competitors. Some stakeholders argue that U.S.
competitiveness may be harmed because a lack of patent availability will drive investment in
certain industries to other countries where such inventions are more clearly patent-eligible.200
Others argue that one effect of Alice/Mayo is a loss of any patent protection for certain inventions,
which will enable competitors to “free ride” off of American innovation.201
Defenses of the Alice/Mayo Framework
Defenders of the current law of Section 101 respond that these criticisms of Alice/Mayo are
overstated, or that the Supreme Court’s reinvigoration of Section 101 has important benefits for
the patent system. As to the subjective or unpredictable nature of Section 101 doctrine, there is
some indication that the Alice/Mayo framework is not quite as unpredictable as is sometimes
claimed.202 Some commentators also observe that uncertainty in patentable subject matter law is
hardly a new phenomenon,203 and may even be “inevitable.”204 A subjective or “amorphous”

196 PTO PSM REPORT, supra note 16, at 34–35 (“ 197. USPTO PSM Report, supra note 16, at 34–35 ("Among members of the public, there was a general consensus that two Among members of the public, there was a general consensus that two
industries have been most directly affected [by the industries have been most directly affected [by the Alice//Mayo framework]: life sciences and computer-related framework]: life sciences and computer-related
technologies.technologies.”"); ); see also BCLT Report, , supra note 16,note 16, at 582–85 (examining the at 582–85 (examining the Alice//Mayo framework framework’'s effects on s effects on
diagnostics, personalized medicine, biosciences, software, and information technology).diagnostics, personalized medicine, biosciences, software, and information technology).
197 See PTO PSM REPORT 198. See USPTO PSM Report, supra note 16,, supra note 16, at 34–35; at 34–35; BCLT Report, , supra note 16, at 582–84.
198 See PTO PSM REPORTnote 16, at 582–84. 199. See USPTO PSM Report, supra note 16,, supra note 16, at 37–38 (characterizing the views on at 37–38 (characterizing the views on Alice//Mayo in the computer industry as in the computer industry as
“"sharply dividedsharply divided”"); ); BCLT Report, , supra note 16, at 582–84.
199 See PTO PSM REPORTnote 16, at 582–84. 200. See USPTO PSM Report, supra note 16,, supra note 16, at 35, 38; at 35, 38; BCLT Report, , supra note 16, at 583.
200note 16, at 583. 201. See, e.g.,, Stoll,Stoll, supra note 23 (“note 23 ("The courtsThe courts’' focus on subject matter eligibility as a mechanism to deny patents for focus on subject matter eligibility as a mechanism to deny patents for
[inventions in diagnostics and personalized medicine] will drive investment into research in these technologies to other [inventions in diagnostics and personalized medicine] will drive investment into research in these technologies to other
areas. We will lose our edge in the world . . . .areas. We will lose our edge in the world . . . .”"); ); accord PTO PSM REPORTUSPTO PSM Report, , supra note 16,note 16, at 34; Kevin Madigan & at 34; Kevin Madigan &
Adam Mossoff, Adam Mossoff, Turning Gold into Lead: How Patent Eligibility Doctrine Is Undermining U.S. Leadership in
Innovation, 24 , 24 GEO. MASON L. REVGeo. Mason L. Rev. 939, 942–44 (2017) (expressing . 939, 942–44 (2017) (expressing “"concern about the U.S. conceding its gold concern about the U.S. conceding its gold
standard patent system to China and Europestandard patent system to China and Europe”" because of the uncertainty of the because of the uncertainty of the Alice//Mayo framework). framework).
201 202. See, e.g.,, Davis, Davis, supra note 23 note 23 (quoting former (quoting former PTOUSPTO Director David Kappos as stating that international competitors Director David Kappos as stating that international competitors
“"no longer have to steal U.S. technology in [biotech and software], since they can now take it for freeno longer have to steal U.S. technology in [biotech and software], since they can now take it for free”).
202"). 203. See Jason D. Reinecke, Jason D. Reinecke, Is the Supreme Court’'s Patentable Subject Matter Test Overly Ambiguous? An Empirical
Test, 2019 , 2019 UTAH L. REVUtah L. Rev. 581, 583 (2019) (empirical study indicating that while . 581, 583 (2019) (empirical study indicating that while “"the [the [Alice//Mayo] test is likely not a ] test is likely not a
beacon of absolute clarity, it is not completely amorphous,beacon of absolute clarity, it is not completely amorphous,”" as patent prosecutors correctly predicted judicial results as patent prosecutors correctly predicted judicial results
67.3% of the time based only on claim language).67.3% of the time based only on claim language).
203 204. See, e.g., Duffy, , Duffy, supra note 113,note 113, at 623–38 (reviewing 100-year history of failed rules and tests for patentable at 623–38 (reviewing 100-year history of failed rules and tests for patentable
subject matter and observing that subject matter and observing that “"instability in the law of patentable subject matterinstability in the law of patentable subject matter”" is a recurring issue) & is a recurring issue) & id. at 616 at 616
(citing 19th century treatise writers noting difficulty and complexity of the patentable subject matter); Risch, (citing 19th century treatise writers noting difficulty and complexity of the patentable subject matter); Risch, supra note note
21,, at 591 (criticizing, in 2008, the at 591 (criticizing, in 2008, the “"currently confused and inconsistent jurisprudence of patentable subject mattercurrently confused and inconsistent jurisprudence of patentable subject matter”"); );
Donald S. Chisum, Donald S. Chisum, The Patentability of Algorithms, 47 U. , 47 U. PITTPitt. L. . L. REVRev. 959, 992 (1986) (noting . 959, 992 (1986) (noting “"confusion and confusion and
arbitrary distinctionsarbitrary distinctions”" in the law of the patentability of computer software resulting from the in the law of the patentability of computer software resulting from the Benson decision). decision).
204 205. Morris, Morris, supra note 106,note 106, at 107 (arguing that the Court at 107 (arguing that the Court’s “intuitive”'s "intuitive" approach to patentable subject matter approach to patentable subject matter
determinations is “inevitable”).
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approach to patentable subject matter, on this view, may have certain benefits, including
flexibility and adaptability to new technologies.205 Moreover, even if one views the current state
of the law as unacceptably vague, courts may eventually clarify or change Section 101 doctrine in
line with the long history of common law development in this area.206
As to the legal correctness of Alice/Mayo, defenders of the framework note that while the
judicially created categories are not directly grounded in the text of Section 101, they have been
treated as part of the law “as a matter of statutory stare decisis going back 150 years.”207 As to
Mayo’s reliance on 19th century English patent law, some commentators defend the Supreme
Court’s “inventive application” requirement as a faithful reading of this precedent.208 Finally,
although the Alice/Mayo framework may overlap with other patent law doctrines, several
commentators and judges of the Federal Circuit argue that Section 101 serves purposes distinct
from Sections 102, 103, and 112.209 For example, even if the invention in Myriad—an isolated
human DNA sequence discovered to be linked to increased breast cancer risk—was novel,
nonobvious, and sufficiently disclosed, some commentators would still argue that the invention
should not be patented based on harm to future innovation or moral concerns about patenting
human DNA.210
Regarding the alleged detrimental effects of the Court’s Section 101 decisions on innovation,
some stakeholders point to countervailing benefits either generally or in certain industries. In
particular, some stakeholders in industries (such as computer software) affected by litigation by
patent assertion entities211 argue that Section 101 is a useful and important tool for weeding out
overly broad or vague patents at the outset of litigation.212 Other commentators point to general
utilitarian or moral benefits of robust exclusions for patents on basic discoveries in science and
nature.213

205determinations is "inevitable"). 206. Id. at 107–09 (arguing that intuitive approach to Section 101 may be at 107–09 (arguing that intuitive approach to Section 101 may be “desirable”"desirable" because because “"there is simply no other there is simply no other
more rigorous and yet durable way of identifying the proper boundaries for patentable subject mattermore rigorous and yet durable way of identifying the proper boundaries for patentable subject matter”" and and “"vagueness vagueness
provides the flexibility necessary to adjust future technological developmentsprovides the flexibility necessary to adjust future technological developments”"); Duffy, ); Duffy, supra note 113,note 113, at 639 ( at 639 (“"[T]he [T]he
traditional doctrines of patentable subject matter—the prohibition against patenting abstract ideas, natural phenomena, traditional doctrines of patentable subject matter—the prohibition against patenting abstract ideas, natural phenomena,
and principles of nature—have survived because . . . they have been amorphous.and principles of nature—have survived because . . . they have been amorphous.”).
206 See PTO PSM REPORT"). 207. See USPTO PSM Report, supra note 16,, supra note 16, at 23–24 (expressing stakeholder views that the Court at 23–24 (expressing stakeholder views that the Court’'s decisions are part of s decisions are part of
the normal common law development of Section 101, and that the Federal Circuitthe normal common law development of Section 101, and that the Federal Circuit’'s subsequent development of the law s subsequent development of the law
may be may be “"headed in the right directionheaded in the right direction”"). 208. ).
207 Bilski v. Kappos, 561 U.S. 593, 602 (2010) (citing Le Roy v. Tatham, 55 U.S. (14 How.) 156, 174–75 (1853)). Bilski v. Kappos, 561 U.S. 593, 602 (2010) (citing Le Roy v. Tatham, 55 U.S. (14 How.) 156, 174–75 (1853)).
208 209. See Brief of Nine Law Professors as Brief of Nine Law Professors as Amicus Curiae in Support of Petitioners at 8–16; Mayo Collaborative Servs. v. in Support of Petitioners at 8–16; Mayo Collaborative Servs. v.
Prometheus Labs., Inc., 566 U.S. 66 (2012) (No. 10-1150), 2011 WL 4071921.Prometheus Labs., Inc., 566 U.S. 66 (2012) (No. 10-1150), 2011 WL 4071921.
209 210. See, e.g., Morris, , Morris, supra note 106, note 106, at 113 (at 113 (“"To be sure, patentable subject matter overlaps with and serves some of To be sure, patentable subject matter overlaps with and serves some of
the same purposes as the other patentability requirements . . . . But only patentable subject matter serves to distinguish the same purposes as the other patentability requirements . . . . But only patentable subject matter serves to distinguish
patentable technology from unpatentable discoveries, information, and human thought and activity.patentable technology from unpatentable discoveries, information, and human thought and activity.”"); Lemley et al., ); Lemley et al.,
supra note 21,note 21, at 1330–32 (distinguishing purpose of Section 101 from Section 112); at 1330–32 (distinguishing purpose of Section 101 from Section 112); accord Mayo, 566 U.S. at 90–91; , 566 U.S. at 90–91;
Athena Diag., Inc. v. Mayo Collaborative Servs., 927 F.3d 1333, 1337–39 (Fed. Cir. 2019) (Dyk, J., concurring in the Athena Diag., Inc. v. Mayo Collaborative Servs., 927 F.3d 1333, 1337–39 (Fed. Cir. 2019) (Dyk, J., concurring in the
denial of rehearing en banc).denial of rehearing en banc).
210 See generally infra “Potential Rationales for Section 101.”
211 211.

See generally infra "Views on the Purposes of Section 101."

212. A patent assertion entity, sometimes called a nonpracticing entity or (pejoratively) a A patent assertion entity, sometimes called a nonpracticing entity or (pejoratively) a “"patent troll,patent troll,”" is a loose term is a loose term
for an individual or organization that seeks to license or litigate patents, but does not itself practice the patented for an individual or organization that seeks to license or litigate patents, but does not itself practice the patented
invention. invention. See Colleen V. Chien, Colleen V. Chien, From Arms Race to Marketplace: The Complex Patent Ecosystem and Its
Implications for the Patent System, 62 , 62 HASTINGSHastings L.J. 297, 326–27 (2010) (discussing distinction among various types L.J. 297, 326–27 (2010) (discussing distinction among various types
of nonpracticing patent entities).of nonpracticing patent entities).
212 PTO PSM REPORT, supra note 16, 213. USPTO PSM Report, supra note 16, at 24–26; at 24–26; BCLT Report, , supra note 16,note 16, at 596; Gugliuzza, at 596; Gugliuzza, supra note 25,note 25, at 652– at 652–
53.53.
213 214. Sarnoff, Sarnoff, supra note 113, note 113, at 106–24 (reviewing asserted utilitarian and moral benefits of robust Section 101 exclusions); see generally infra "Views on the Purposes of Section 101." 215.

USPTO PSM Report, supra note 16, at 27.

216.

Id.

217. at 106–24 (reviewing asserted utilitarian and moral benefits of robust Section 101
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Lastly, in response to concerns about the Alice/Mayo framework’s effect on international
competitiveness, some commentators assert that these changes are good for the United States as a
geopolitical matter.214 In particular, restricted patent-eligibility standards may benefit U.S.
consumers if a lack of patent protection leads to increased competition and lower prices for
certain products without harming innovation.215
Potential Rationales for Section 101
More broadly, there is a long-running debate over the functions and purposes that Section 101
serves in the patent system. For its part, the modern Supreme Court has largely settled on the
“preemption rationale” for the judicially created subject matter exclusions. These decisions assert
that abstract ideas, laws of nature, and natural phenomena should not be patentable because
permitting a monopoly on the “‘basic tools of scientific and technological work’ . . . might tend to
impede innovation more than it would tend to promote it,”216 in that such patents would
“significantly impede future innovation.”217 The gist of the preemption rationale is that Section
101 functions to prevent patents that reach so broadly that they “threaten downstream innovation”
by preempting all uses of a natural law, abstract idea, or fundamental research tools.218
The preemption rationale is not the only potential justification for Section 101, however.
Although a complete survey of the various rationales proffered for Section 101 is beyond the
scope of this report, at least four broad categories of rationales for Section 101 have been
proposed.219
First, some commentators argue that Section 101’s purpose is to identify certain patents or
categories of patents that should not be granted because their economic harms exceed their
benefits—that is, their net social costs are negative for innovation, or more generally.220
Preemption theory, which claims that certain overbroad patents should be denied patent
protection under Section 101 because of their negative effects on downstream innovation, is an
example from this group.221

exclusions); see generally infra “Potential Rationales for Section 101.”
214 PTO PSM REPORT, supra note 16, at 27.
215 Id.
216 Mayo Collaborative Servs. v. Prometheus Labs., Inc., 566 U.S. 66, 71 (2012) (quoting Gottschalk v. Benson, 409 Mayo Collaborative Servs. v. Prometheus Labs., Inc., 566 U.S. 66, 71 (2012) (quoting Gottschalk v. Benson, 409
U.S. 63, 67 (1972)); Alice Corp. Pty. v. CLS Bank IntU.S. 63, 67 (1972)); Alice Corp. Pty. v. CLS Bank Int’'l, 573 U.S. 208, 216 (2014) (l, 573 U.S. 208, 216 (2014) (“"We have described the concern We have described the concern
that drives [the ineligible categories of patentable subject matter] as one of pre-emption.that drives [the ineligible categories of patentable subject matter] as one of pre-emption.”).
217"). 218. Mayo, 566 U.S. at 91., 566 U.S. at 91.
218 219. See, e.g., Lemley et al., , Lemley et al., supra note 21,note 21, at 1346–47; at 1346–47; accord Benson, 409 U.S. at 72 (rejecting patent because it would , 409 U.S. at 72 (rejecting patent because it would
“"wholly pre-empt the mathematical formula and in practical effect would be a patent on the algorithm itselfwholly pre-empt the mathematical formula and in practical effect would be a patent on the algorithm itself”").). But see
Katherine J. Strandburg, Katherine J. Strandburg, Much Ado About Preemption, 50 , 50 HOUSHous. L. . L. REVRev. 563, 566 (2012) (critiquing preemption . 563, 566 (2012) (critiquing preemption
rationale’s “rationale's "sole focus on broad downstream impactsole focus on broad downstream impact”" as not providing a satisfactory explanation for the Supreme as not providing a satisfactory explanation for the Supreme
Court’Court's Section 101 case law).s Section 101 case law).
219 220. See generally J. Jonas Anderson, J. Jonas Anderson, Applying Patent-Eligible Subject Matter Restrictions, 17 , 17 VANDVand. J. . J. ENT. & TECHEnt. & Tech. L. . L.
267, 269–40, 279–86 (2015) (surveying the 267, 269–40, 279–86 (2015) (surveying the “"diverse set of proposed theoriesdiverse set of proposed theories”" of Section 101 and categorizing them of Section 101 and categorizing them
into several broad categories).into several broad categories).
220 221. See Anderson, Anderson, supra note 219, note 220, at 284–85 (overviewing this group of theories); at 284–85 (overviewing this group of theories); see, e.g., David S. Olson, , David S. Olson, Taking the
Utilitarian Basis for Patent Law Seriously: The Case for Restricting Patentable Subject Matter, 82 , 82 TEMPTemp. L. . L. REVRev. 181, . 181,
184 (2009) (arguing that patentable subject matter doctrine should be driven by looking at when 184 (2009) (arguing that patentable subject matter doctrine should be driven by looking at when “"granting a patent right granting a patent right
for this type of innovation causes more loss to society than gainfor this type of innovation causes more loss to society than gain”).
221 See supra note 218 and accompanying text.
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Second—in what is in some sense a special case of the first rationale—other commentators assert
that Section 101’s purpose is to identify and deny patents to categories of inventions that would
have been developed even without a patent incentive.222 For example, several commentators have
argued the patents on business methods should be excluded under Section 101 either because they
affirmatively harm innovation and the economy, or because they are simply unnecessary because
sufficient incentives to create business methods would exist even if patents are unavailable.223
Third, some commentators assert that Section 101 (or elements of Section 101 doctrine) are based
not on economic considerations but on moral or ethical concerns.224 For example, the judicial
prohibition on patenting products of nature—such as human DNA sequences—may be motivated
by noneconomic, deontological notions of human dignity, or the inviolability of natural
creation.225
Finally, some commentators believe that Section 101 serves no independent purpose in patent law
not already better served by other patentability requirements.226 On this view, Section 101’s
judicially created exceptions to patentable subject matter should simply be eliminated as an
independent requirement for patentability, in favor of a rigorous application of the other
patentability requirements in Sections 102, 103, and 112 of the Patent Act.227
Potential Options for Section 101
Before examining the particular approaches used in PTO guidance and proposed legislative
reforms, this section will review some of the general ways in which Section 101 may or may not
be reformed. These different paths are introduced to contextualize the current Section 101 reform
proposals within the universe of possible reforms. This list is not exhaustive, nor are each of these
options necessarily mutually exclusive.
At a general level, most of the proposed paths forward for Section 101 fall into one of four
categories.228 First, some oppose any legislative intervention, proposing instead to allow the

222"). 222.

See supra note 219 and accompanying text.

223. See Anderson, supra note 220, See Anderson, supra note 219, at 285–86 (overviewing this group of theories); at 285–86 (overviewing this group of theories); see, e.g., Pamela Samuelson, Benson, Pamela Samuelson, Benson
Revisited: The Case Against Patent Protection for Algorithms and Other Computer Program-Related Inventions, 39 , 39
EMORYEmory L.J. 1025, 1136 (1990) (arguing that software should not be patentable in part because L.J. 1025, 1136 (1990) (arguing that software should not be patentable in part because “"the fact that this growth the fact that this growth
[in the software industry] has occurred without the aid of patent protection is powerful evidence that patent protection [in the software industry] has occurred without the aid of patent protection is powerful evidence that patent protection
is not necessary for the software industry to thriveis not necessary for the software industry to thrive”).
223"). 224. See, e.g.,, Rochelle Cooper Dreyfuss, Rochelle Cooper Dreyfuss, Are Business Method Patents Bad for Business?, 16 , 16 SANTA CLARA COMPUTER
& HIGH TECHSanta Clara Computer & High Tech. L.J. 263, 274 (2000) (arguing that business method patents are unwise because they . L.J. 263, 274 (2000) (arguing that business method patents are unwise because they “"adversely affect adversely affect
innovation, and worse, the economyinnovation, and worse, the economy”"); ); accord Bilski v. Kappos, 561 U.S. 593, 651 (2010) (Stevens, J., concurring in Bilski v. Kappos, 561 U.S. 593, 651 (2010) (Stevens, J., concurring in
the judgment) (arguing that business methods should not be patentable because there are the judgment) (arguing that business methods should not be patentable because there are “"ample incentives to develop ample incentives to develop
business methods even without patent protectionbusiness methods even without patent protection”" (quoting Dan L. Burk & Mark A. Lemley, (quoting Dan L. Burk & Mark A. Lemley, Policy Levers in Patent
Law, 89 , 89 VAVa. L. . L. REVRev. 1575, 1618 (2003))).. 1575, 1618 (2003))).
224 225. See Anderson, Anderson, supra note 219, note 220, at 286 (overviewing this group of theories); at 286 (overviewing this group of theories); see, e.g., Sarnoff, , Sarnoff, supra note 113,note 113, at 84– at 84–
90 (surveying religious and deontological bases for prohibition on patenting science, nature, and ideas); Tun-Jen 90 (surveying religious and deontological bases for prohibition on patenting science, nature, and ideas); Tun-Jen
Chiang, Chiang, Competing Visions of Patentable Subject Matter, 82 , 82 GEO. WASH. L. REVGeo. Wash. L. Rev. 1858, 1860 (2014) (arguing that . 1858, 1860 (2014) (arguing that
Section 101 determinations are Section 101 determinations are “"often about noneconomic moral valuesoften about noneconomic moral values”).
225 Chiang, supra note 224, at 1873–81.
226"). 226.

Chiang, supra note 225, at 1873–81.

227. See Anderson, Anderson, supra note 219, note 220, at 280 (overviewing this group of theories).at 280 (overviewing this group of theories).
227 228. See, e.g., Risch, , Risch, supra note 21,note 21, at 591–94 (articulating this view); Davis, at 591–94 (articulating this view); Davis, supra note 23 note 23 (quoting former (quoting former PTO
USPTO Director David Kappos as calling for abolishing Section 101 and instead Director David Kappos as calling for abolishing Section 101 and instead “"faithfully applying other areas of patent law faithfully applying other areas of patent law
to ensure that patents are not obvious or anticipated or lacking in written descriptionto ensure that patents are not obvious or anticipated or lacking in written description”).
228"). 229. See David O. Taylor, David O. Taylor, Amending Patent Eligibility, 50 U.C. , 50 U.C. DAVIS L. REVDavis L. Rev. 2149, 2189–2211 (2017) (listing proposed . 2149, 2189–2211 (2017) (listing proposed
Section 101 reforms, including a European-style Section 101 reforms, including a European-style “"laundry listlaundry list”" of exclusions, a new of exclusions, a new “"workable eligibility standard,workable eligibility standard,”" or or
the elimination of the judicially created ineligible categories); the elimination of the judicially created ineligible categories); PTO PSM REPORTUSPTO PSM Report, , supra note 16,note 16, at 39–46 (reviewing at 39–46 (reviewing
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courts to continue to develop and refine the standards for patent eligibility.229 Second, some
propose replacing the Alice/Mayo framework with an explicit list of subject matter that is patent-
eligible or -ineligible, similar to the approach that is used for European patents.230 Third, some
propose replacing the Alice/Mayo framework with a different, usually lower, standard for patent
eligibility, such as a requirement that the invention result from human effort, exist outside the
human mind, or contribute to the technological arts.231 Fourth, some propose to do away with any
limitations on patentable subject matter, beyond the four statutory categories and other existing
statutory patentability requirements.232
Continued Common Law Judicial Development
One option is for Congress to leave Section 101 as it is, and allow the courts and the PTO to
continue developing the law of patent-eligible subject matter. Stakeholders and commentators
may support this option for several different reasons. Some may disagree that the Alice/Mayo
framework is as indeterminate or as harmful to innovation as the critics claim.233 Other
commentators, even if they accept the criticisms directed at Alice/Mayo, believe that the courts
will eventually refine, clarify, or otherwise improve the law of patentable subject matter given
more time for judicial development.234 Still other commentators support the current law of
Section 101 as affirmatively good for innovation and society because it precludes property rights
in fundamental aspects of science, nature, and ideas,235 or serves as an important mechanism to
weed out overly broad patents or obtain early dismissal of unmeritorious patent litigation.236
Supporters of continued judicial development may point to the administrative guidance put forth
by the PTO237 and significant Section 101 decisions of the Federal Circuit238 as promising steps in

proposed Section 101 recommendations, including continued judicial and/or administrative development, codification proposed Section 101 recommendations, including continued judicial and/or administrative development, codification
of explicitly defined Section 101 exceptions, or new standards for patent eligibility); of explicitly defined Section 101 exceptions, or new standards for patent eligibility); BCLT Report, , supra note 16,note 16, at at
562–66 (same).562–66 (same).
229 See PTO PSM REPORT 230. See USPTO PSM Report, supra note 16,, supra note 16, at 39–41; at 39–41; BCLT Report, , supra note 16, at 566.
230note 16, at 566. 231. See Taylor, Taylor, supra note 228,note 229, at 2198–2201; at 2198–2201; PTO PSM REPORTUSPTO PSM Report, , supra note 16,note 16, at 43–45; at 43–45; BCLT Report, , supra note note
16,, at 564. at 564.
231 232. See Taylor, Taylor, supra note 228, atnote 229, at 2202–06; 2202–06; PTO PSM REPORTUSPTO PSM Report, , supra note 16,note 16, at 41–43; at 41–43; BCLT Report, , supra note 16,
note 16, at 563–65.at 563–65.
232 233. See, e.g., Risch, , Risch, supra note 21,note 21, at 591–94; at 591–94; see generally "“Requirements for Patentability”" (reviewing requirements (reviewing requirements
for patentability under Sections 102, 103, and 112 of the Patent Act).for patentability under Sections 102, 103, and 112 of the Patent Act).
233 See BCLT Report, supra note 16, at 566.
234 See PTO PSM REPORT 234.

See BCLT Report, supra note 16, at 566.

235.

See USPTO PSM Report, supra note 16, at 39.

236.

Sarnoff Testimony, supra note 26, at 1.

237. , supra note 16, at 39.
235 Sarnoff Testimony, supra note 26, at 1.
236 See Patent Eligibility Hearings, supra note 31 note 29 (statement of Prof. Paul R. Gugliuzza, Boston University School of (statement of Prof. Paul R. Gugliuzza, Boston University School of
Law), at 1, https://www.judiciary.senate.gov/imo/media/doc/Gugliuzza%20Testimony.pdf [hereinafter Gugliuzza Law), at 1, https://www.judiciary.senate.gov/imo/media/doc/Gugliuzza%20Testimony.pdf [hereinafter Gugliuzza
Testimony] (Testimony] (“"[T]he eligibility requirement, though imperfect, plays a crucial role in reducing litigation costs by giving [T]he eligibility requirement, though imperfect, plays a crucial role in reducing litigation costs by giving
courts a mechanism to quickly dismiss infringement claims that plainly lack merit.courts a mechanism to quickly dismiss infringement claims that plainly lack merit.”).
237"). 238. See infra “"Administrative Developments: PTO Subject Matter Eligibility Guidance.”
238 in the USPTO ." 239. See, e.g., Am. Axle & Mfg. v. Neapco Holdings, 967 F.3d 1285 (Fed. Cir. 2020); Yu v. Apple Inc., 1 F.4th 1040 , Am. Axle & Mfg. v. Neapco Holdings, 967 F.3d 1285 (Fed. Cir. 2020); Yu v. Apple Inc., 1 F.4th 1040
(Fed. Cir. 2021); Chamberlain Grp., Inc. v. Techtronic Indus. Co., 935 F.3d 1341 (Fed. Cir. 2019); ChargePoint, Inc. v. (Fed. Cir. 2021); Chamberlain Grp., Inc. v. Techtronic Indus. Co., 935 F.3d 1341 (Fed. Cir. 2019); ChargePoint, Inc. v.
SemaConnect, Inc., 920 F.3d 759 (Fed. Cir. 2019); Athena Diagnostics, Inc. v. Mayo Collaborative Servs., LLC, 915 SemaConnect, Inc., 920 F.3d 759 (Fed. Cir. 2019); Athena Diagnostics, Inc. v. Mayo Collaborative Servs., LLC, 915
F.3d 743 (Fed. Cir. 2019); Vanda Pharms. Inc. v. West-Ward Pharms. IntF.3d 743 (Fed. Cir. 2019); Vanda Pharms. Inc. v. West-Ward Pharms. Int’'l Ltd., 887 F.3d 1117 (Fed. Cir. 2018); Aatrix l Ltd., 887 F.3d 1117 (Fed. Cir. 2018); Aatrix
Software v. Green Shades Software, 882 F. 3d 1121 (Fed. Cir. 2018); Berkheimer v. HP Inc., 881 F.3d 1360 (Fed. Cir. Software v. Green Shades Software, 882 F. 3d 1121 (Fed. Cir. 2018); Berkheimer v. HP Inc., 881 F.3d 1360 (Fed. Cir.
2018); Enfish, LLC v. Microsoft Corp., 822 F.3d 1327 (Fed. Cir. 2016); Finjan, Inc. v. Blue Coat Systems, Inc., 879 2018); Enfish, LLC v. Microsoft Corp., 822 F.3d 1327 (Fed. Cir. 2016); Finjan, Inc. v. Blue Coat Systems, Inc., 879
F.3d 1299 (Fed. Cir. 2018); McRO, Inc. v. Bandai Namco Games Am. Inc., 837 F.3d 1299 (Fed. Cir. 2016); Bascom F.3d 1299 (Fed. Cir. 2018); McRO, Inc. v. Bandai Namco Games Am. Inc., 837 F.3d 1299 (Fed. Cir. 2016); Bascom
Global Internet Services, Inc. v. AT&T Mobility LLC, 827 F.3d 1341 (Fed. Cir. 2016); Ariosa Diagnostics, Inc. v. Global Internet Services, Inc. v. AT&T Mobility LLC, 827 F.3d 1341 (Fed. Cir. 2016); Ariosa Diagnostics, Inc. v.
Sequenom, Inc., 788 F.3d 1371 (Fed. Cir. 2015); DDR Holdings, LLC v. Hotels.com, L.P., 773 F.3d 1245 (Fed. Cir.
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the development of Section 101 after the Alice, Mayo, and Myriad decisions. Opponents of
maintaining the legal status quo, for their part, observe that the Supreme Court has not shown
much interest in revisiting its Section 101 jurisprudence despite many opportunities,239 and that
the PTO and the Federal Circuit are bound by the Court’s decisions.
Specific Statutory List of Included or Excluded Subject Matter Categories
Another potential route for reform would be to amend Section 101 to replace the Alice/Mayo
framework with a more specific list of subject matter that is patent-eligible or ineligible.
Currently, Section 101 contains a broad list of included subject matter categories (processes,
machines, manufactures, and compositions of matter), and most of the doctrine focuses on the
three judicially created ineligible categories: laws of nature, natural phenomena, and abstract
ideas.240 The “laundry list” approach would seek to make Section 101 clearer and more
predictable by more specifically defining categories of eligible or ineligible subject matter.241
Depending on how this sort of proposal is structured, it would retain the notion of ineligible
classes of subject matter, but define such categories differently, more precisely, and perhaps more
narrowly than the common law exceptions under the Alice/Mayo framework.
The European Patent Convention’s (EPC’s) approach to patent eligibility offers a potential model
for this type of approach.242 Under EPC article 52(1), patent-eligible subject matter reaches “all
fields of technology, provided that they are new, involve an inventive step and are susceptible of
industrial application.”243 At the same time, EPC article 52(2) defines specific subject matter that
is not patentable when claimed “as such”:
(a) discoveries, scientific theories and mathematical methods;
(b) aesthetic creations;
(c) schemes, rules and methods for performing mental acts, playing games or doing
business, and programs for computers;
(d) presentations of information.244
EPC article 53 further denies patents on inventions that are “contrary to [public order] or
morality,” claim “plant and animal varieties,” or claim “methods for treatment of the human or
animal body by surgery or therapy and diagnostic methods practised on the human or animal
body.”245
Assuming that the new statutory categories are more clearly defined than existing judicial
categories, a potential virtue of the laundry-list approach is greater clarity and predictability in the
sort of inventions that are patentable.246 This approach would also more firmly ground subject
matter determinations in the statutory text. On the other hand, the list-of-specific-exclusions

2014).
239 See infra “Judicial Developments.”
240 See supra “The Current Law of Section 101.”
241 See Taylor, supra note 228, at 2198, 2200 (coining this term).
242 BCLT Report, supra note 16, at 564.
243 Convention on the Grant of European Patents art. 52(1), Oct. 5, 1973, 1065 U.N.T.S. 254 (as amended),
https://www.epo.org/law-practice/legal-texts/html/epc/2016/e/EPC_conv_20190401_en_20190326.pdf.
244 Id. art. 52(2)–(3).
245 Id. art. 53.
246 See Taylor, supra note 228, at 2200.
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approach might be less flexible and less able to adapt to unforeseen new technologies than other
options.247 It might also, to some degree, replace case-by-case judicial judgments of eligibility
with more categorical legislative ones, which may be a virtue or a vice depending on one’s
perspective.248
Replace Judicial Exceptions with a Different Standard
A third group of proposed Section 101 reforms seeks to replace the Alice/Mayo framework with a
new statutory standard for assessing patent eligibility.249 Proposals in this category are fairly
diverse, but common elements in proposed new standards would limit patent eligibility to
inventions that
 result from human effort;250
 contribute to the technological arts;251
 have practical utility or application;252
 cannot be solely performed in the human mind;253
 do not preempt all practical uses of a law of nature, abstract idea, or natural
phenomenon.254
Usually, the proposed new patentability standard would supersede the three judicially created
subject matter exclusions and the two-step Alice/Mayo test.255
Several proposed new standards blend more than one of these elements. For example, the
American Intellectual Property Law Association has submitted a Section 101 reform proposal that
replaces the Alice/Mayo framework with a single exception to patent eligibility if an invention
“exists in nature independently of and prior to any human activity” or “is performed solely in the
human mind.”256 A 2017 proposal by the American Bar Association (ABA) would explicitly allow
patenting “practical applications” of laws of nature, natural phenomena, and abstract ideas, so
long as the patent claim does not “preempt the use by others of all practical applications of the
law of nature, natural phenomenon, or abstract idea.”257
It is difficult to generalize given the significant differences among the various proposals in this
category, but stakeholders may wish to consider whether proposed new standards would provide

247 See id. at 2201.
248 Compare id. at 2193–97 (arguing that judicial “policymaking”Sequenom, Inc., 788 F.3d 1371 (Fed. Cir. 2015); DDR Holdings, LLC v. Hotels.com, L.P., 773 F.3d 1245 (Fed. Cir. 2014). 240.

See infra "Judicial Developments."

241. See supra "The Law of Section 101." 242.

See Taylor, supra note 229, at 2198, 2200 (coining this term).

243.

BCLT Report, supra note 16, at 564.

244.

Convention on the Grant of European Patents art. 52(1), Oct. 5, 1973, 1065 U.N.T.S. 254 (as amended), https://www.epo.org/law-practice/legal-texts/html/epc/2016/e/EPC_conv_20190401_en_20190326.pdf.

245.

Id. art. 52(2)–(3).

246.

Id. art. 53.

247.

See Taylor, supra note 229, at 2200.

248.

See id. at 2201.

249. Compare id. at 2193–97 (arguing that judicial "policymaking" under Section 101 should be constrained), under Section 101 should be constrained), with
Morris, Morris, supra note 106, note 106, at 107–17 (arguing that a subjective, intuitive, case-by-case, judgment-based approach to at 107–17 (arguing that a subjective, intuitive, case-by-case, judgment-based approach to
Section 101 is inevitable and Section 101 is inevitable and “"perhaps even desirableperhaps even desirable”).
249"). 250. For examples of this sort of proposal, see Taylor, For examples of this sort of proposal, see Taylor, supra note 228,note 229, at 2202–07; at 2202–07; PTO PSM REPORTUSPTO PSM Report, , supra note 16,note 16, at at
42–43, 59–62; 42–43, 59–62; BCLT Report, , supra note 16, at 563–65.
250note 16, at 563–65. 251. See, e.g.,, Taylor, Taylor, supra note 228, note 229, at 2202–05;at 2202–05; BCLT Report, , supra note 16, at 563.
251note 16, at 563. 252. See, e.g.,, PTO PSM REPORTUSPTO PSM Report, , supra note 16,note 16, at 42, 64. at 42, 64.
252 253. See, e.g.,, PTO PSM REPORTUSPTO PSM Report, , supra note 16,note 16, at 43; at 43; BCLT Report, , supra note 16,note 16, at 563–64; at 563–64; Taylor, Taylor, supra note 228,
note 229, at 2205–07.at 2205–07.
253 254. See, e.g.,, BCLT Report, , supra note 16, at 563.
254note 16, at 563. 255. See, e.g.,, PTO PSM REPORTUSPTO PSM Report, supra note 16, at 60–61. 256.

See, e.g., BCLT Report, supra note 16, at 563–65.

257. , supra note 16, at 60–61.
255 See, e.g., BCLT Report, supra note 16, at 563–65.
256 Am. Intellectual Prop. Law Ass Am. Intellectual Prop. Law Ass’'n, Joint AIPLA-IPO Proposal on Patent Eligibility (May 2018), https://www.aipla.org/policy-advocacy/legislative/joint-aipla-ipo-proposal-on-patent-eligibility. 258.

See USPTO PSM Report, supra note 16, at 60.

259. See Taylor, supra note 229,n, Joint AIPLA-IPO Proposal on Patent Eligibility (May 2018),
https://www.aipla.org/policy-advocacy/legislative/joint-aipla-ipo-proposal-on-patent-eligibility.
257 See PTO PSM REPORT, supra note 16, at 60.
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greater clarity and predictability in patent-eligibility law, while still being flexible enough to
adapt to new technologies.258
Eliminate Implied Patentable Subject Matter Limits
A final option is to eliminate the Alice/Mayo framework and judicially created exceptions to
patent eligibility altogether, without replacing them with a new standard.259 Several commentators
have argued that patent-eligibility doctrine serves no purpose that is not already served by the
existing statutory patentability requirements of utility, novelty, obviousness, written description,
definiteness, and enablement.260 On this view, the appropriate course would be for Congress to
simply eliminate the nonstatutory eligibility requirements (i.e., the judicial prohibitions on
patenting laws of nature, natural phenomena, and abstract ideas) in favor of the application of the
patentability requirements of Sections 102, 103, and 112 of the Patent Act.261
Supporters of this approach argue that it advances the policy concerns motivating Section 101
law, but does so in a “more consistent and more rigorous” manner.262 Opponents argue that
Section 101 serves important purposes that are distinct from the other patentability requirements,
which would be lost if the judicial exceptions were eliminated.263
Recent Developments in Patent-Eligible Subject
Matter Reform
The Supreme Court’s modern patentable subject matter jurisprudence has led to responses from
the courts, the PTO, and Congress. This section reviews recent judicial, administrative, and
legislative developments on patent-eligible subject matter standards and proposed reform.
Judicial Developments
Since its 2014 decision in Alice, the Supreme Court has denied dozens of petitions for certiorari
(i.e., requests that the Court hear an appeal) on Section 101 issues, despite calls from some patent
law stakeholders asking the Court to revisit its patent-eligible subject matter jurisprudence.264 For
example, in Sequenom v. Ariosa Diagnostics, Inc.,265 the Supreme Court denied certiorari despite
22 amicus briefs supporting certiorari and calls from commentators, stakeholders, and Federal

258 See Taylor, supra note 228, at 2189–97 (articulating general principles for evaluating proposed Section 101 at 2189–97 (articulating general principles for evaluating proposed Section 101
reforms).
259 See BCLT Report, supra note 16, at 565.
260 See Risch, supra note 21,reforms). 260.

See BCLT Report, supra note 16, at 565.

261. See Risch, supra note 21, at 594, 606–09; Taylor, at 594, 606–09; Taylor, supra note 228, at 2171–89.
261note 229, at 2171–89. 262.

Risch, supra note 21, at 606–09.

263. Risch, supra note 21, at 606–09.
262 Id. at 594; at 594; accord Taylor, Taylor, supra note 228, at 2211.
263note 229, at 2211. 264. See, e.g., Mayo Collaborative Servs. v. Prometheus Labs., Inc., 566 U.S. 66, 91 (2012) (relying on concerns about , Mayo Collaborative Servs. v. Prometheus Labs., Inc., 566 U.S. 66, 91 (2012) (relying on concerns about
preemption to preemption to “"decline the Governmentdecline the Government’'s invitation to substitute §§ 102, 103, and 112 inquiries for the better s invitation to substitute §§ 102, 103, and 112 inquiries for the better
established inquiry under § 101established inquiry under § 101”"); ); see supra note 209 note 210 (citing academic sources); (citing academic sources); see generally “Potential Rationales for
Section 101.”
264"Views on the Purposes of Section 101." 265. See Burman York Mathis III, Burman York Mathis III, Supreme Court Denies 43rd Petition for Cert on 101 Grounds in Villena v. Iancu, Villena v. Iancu,
IPWATCHDOGIPWatchdog (Sept. 3, 2019), https://www.ipwatchdog.com/2019/06/16/supreme-court-denies-43rd-petition-cert-101- (Sept. 3, 2019), https://www.ipwatchdog.com/2019/06/16/supreme-court-denies-43rd-petition-cert-101-
grounds-villena-v-iancu/id=110425/grounds-villena-v-iancu/id=110425/.
265. 266. See 788 F.3d 1371 (Fed. Cir. 2015), 788 F.3d 1371 (Fed. Cir. 2015), cert. denied, 579 U.S. 928 (2016)., 579 U.S. 928 (2016).
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Circuit judges urging the Court to take the case to clarify Section 101.266 Similarly, in opinions
concerning rehearing en banc in Athena Diagnostics, Inc. v. Mayo Collaborative Services,267 all
of the active judges on the Federal Circuit called upon the Supreme Court (or Congress) to
change Section 101 law to clearly allow for the patenting of diagnostic methods.268 The Supreme
Court nonetheless denied certiorari in Athena and again declined to revisit its Section 101 case
law.269
The most prominent recent Section 101 case that the Court declined to hear was American Axle &
Manufacturing v. Neapco Holdings.270 That case was thought by some observers to be an ideal
vehicle for the Court because the patented technology—a method for manufacturing driveline
shafts for automotive vehicles—was tangible and relatively straightforward, yet the lower courts
held it ineligible as directed to a law of nature.271 As in Athena, the Federal Circuit was closely
divided with respect to rehearing American Axle en banc, dividing 6-6, with 5 judges averring
that “[Federal Circuit] rulings on patent eligibility have become so diverse and unpredictable as to
have a serious effect on the innovation incentive in all fields of technology.”272 Many
stakeholders again supported the petition for certiorari in American Axle, including a brief filed
jointly by Senator Tillis, the Hon. Paul R. Michel (a former Chief Judge of the Federal Circuit),
and David J. Kappos (a former PTO Director).273 The Supreme Court invited the views of the
Solicitor General, who filed a brief supporting a partial grant of certiorari in American Axle.274
The Supreme Court declined to hear the case.275
In light of the Supreme Court’s apparent reluctance to revisit Section 101, some stakeholders
have called for Congress to intervene on the issue.

266 267. BCLT Report, , supra note 16,note 16, at 577 (describing at 577 (describing Sequenom as a as a “"case that many Federal Circuit jurists, scholars, and case that many Federal Circuit jurists, scholars, and
practitioners regarded as an ideal vehicle for [the Court to] clarify[] patent eligibility standardspractitioners regarded as an ideal vehicle for [the Court to] clarify[] patent eligibility standards”"); USPTO); PTO PSM Report, ,
supra note 16,note 16, at 11 (same); at 11 (same); SCOTUSBLOGScotusblog, , Sequenom, Inc. v. Ariosa Diagnostics, Inc., .,
https://www.scotusblog.com/case-files/cases/sequenom-inc-v-ariosa-diagnostics-inc/ (last visited https://www.scotusblog.com/case-files/cases/sequenom-inc-v-ariosa-diagnostics-inc/ (last visited Nov. 21, 2022)
Mar. 31, 2025) (linking to 22 amicus briefs in support of the petition for certiorari).(linking to 22 amicus briefs in support of the petition for certiorari).
267 268. Athena Diagnostics, Inc. v. Mayo Collaborative Servs., LLC, 915 F.3d 743 (Fed. Cir. 2019), Athena Diagnostics, Inc. v. Mayo Collaborative Servs., LLC, 915 F.3d 743 (Fed. Cir. 2019), cert. denied, 140 S. Ct. , 140 S. Ct.
855 (2020).855 (2020).
268 269. See Athena Diagnostics, Inc. v. Mayo Collaborative Servs., LLC, 927 F.3d 1333, 1335 (Fed. Cir. 2019) (opinions Athena Diagnostics, Inc. v. Mayo Collaborative Servs., LLC, 927 F.3d 1333, 1335 (Fed. Cir. 2019) (opinions
regarding the denial of rehearing en banc);regarding the denial of rehearing en banc); CRS Legal Sidebar LSB10344, CRS Legal Sidebar LSB10344, Judges Urge Congress to Revise What Can
Be Patented, , coordinated by Kevin by Kevin T. RichardsJ. Hickey (2020) (reviewing the Federal Circuit (reviewing the Federal Circuit’'s opinions in s opinions in Athena Diagnostics).).
269 140 S. Ct. 855 (2020).
270 967 F.3d 1285 (Fed. Cir. 2020), cert. denied, 142 S. Ct. 2902 (2022).
271 Id. at 1292–99.
272 270.

140 S. Ct. 855 (2020).

271.

967 F.3d 1285 (Fed. Cir. 2020), cert. denied, 142 S. Ct. 2902 (2022).

272.

Id. at 1292–99.

273. Am. Axle & Mfg., Inc. v. Neapco Holdings LLC, 966 F.3d 1347, 1357 (Fed. Cir. 2020) (Newman, J., dissenting Am. Axle & Mfg., Inc. v. Neapco Holdings LLC, 966 F.3d 1347, 1357 (Fed. Cir. 2020) (Newman, J., dissenting
from the denial of rehearing en banc).from the denial of rehearing en banc).
273 274. See Am. Axle & Mfg. v. Neapco Holdings LLC (U.S. No. 20-891), https://www.supremecourt.gov/ Am. Axle & Mfg. v. Neapco Holdings LLC (U.S. No. 20-891), https://www.supremecourt.gov/
search.aspx?filename=/docket/docketfiles/html/public/20-891.html (Supreme Court docket linking to amicus briefs).search.aspx?filename=/docket/docketfiles/html/public/20-891.html (Supreme Court docket linking to amicus briefs).
274 275. See Brief for the United States as Amicus Curiae, Am. Axle & Mfg. v. Neapco Holdings LLC, No. 20-891 (U.S. Brief for the United States as Amicus Curiae, Am. Axle & Mfg. v. Neapco Holdings LLC, No. 20-891 (U.S.
May 24, 2022), https://www.supremecourt.gov/DocketPDF/20/20-891/226156/20220524150114156_20-891%20-May 24, 2022), https://www.supremecourt.gov/DocketPDF/20/20-891/226156/20220524150114156_20-891%20-
%20American%20Axle%20CVSG.pdf%20American%20Axle%20CVSG.pdf.
275. 276. 142 S. Ct. 2902 (2022). 142 S. Ct. 2902 (2022).
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Administrative Developments: PTO Subject Matter Eligibility
Guidance
In 2019, the PTO issued Revised Patent Subject Matter Eligibility Guidance (the 2019 Guidance)
to assist PTO patent examiners in determining subject matter eligibility for patent applications.276
The PTO noted that the “legal uncertainty” surrounding the Alice/Mayo framework “poses unique
challenges” for the agency, which has thousands of patent examiners who must make patent-
eligibility determinations on hundreds of thousands of applications each year.277 Accordingly, the
PTO issued revised guidance to its patent examiners to provide “more clarity and predictability”
in their Section 101 determinations.278
The PTO subsequently incorporated the 2019 Guidance into the Manual of Patent Examining
Procedure (MPEP), which guides PTO patent examiners in their review of patent applications.279
The 2019 Guidance made at least two major changes to how patent examiners evaluate whether a
patent application claims patent-ineligible subject matter. First, the Guidance seeks to provide a
clearer definition of what constitutes an ineligible “abstract idea.”280 Previously, examiners would
make that determination by comparing the patent claim at issue to those found to be ineligible
“abstract ideas” in previous judicial cases.281 The PTO found that this approach had become
“impractical” because of an expanding volume of sometimes contradictory Section 101 case
law.282 The 2019 Guidance “distills” the case law into three categories that examiners will treat as
“abstract ideas”:
1) Mathematical concepts—mathematical relationships, mathematical formulas or
equations, mathematical calculations;
2) Certain methods of organizing human activity – fundamental economic principles or
practices (including hedging, insurance, mitigating risk); commercial or legal interactions
(including agreements in the form of contracts; legal obligations; advertising, marketing or
sales activities or behaviors; business relations); managing personal behavior or
relationships or interactions between people (including social activities, teaching, and
following rules or instructions); and

276 277.

See, e.g., Athena Diagnostics, Inc. v. Mayo Collaborative Servs., LLC, 927 F.3d 1333, 1337 (Fed. Cir. 2019) (Hughes, J., concurring in the denial of rehearing en banc) (noting that "we are bound by the Supreme Court['s]" precedent even if the result is "problematic" for diagnostic patents in the view of some Federal Circuit judges).

278.

See, e.g. Trinity Info Media, LLC v. Covalent, Inc., 72 F.4th 1355 (Fed. Cir. 2023); CardioNet, LLC v. InfoBionic, Inc, 955 F.3d 1358 (Fed. Cir. 2020); Illumina, Inc. v. Ariosa Diagnostics, Inc., 967 F.3d 1319 (Fed. Cir. 2020); Athena Diagnostics, Inc. v. Mayo Collaborative Servs., LLC, 915 F.3d 743 (Fed. Cir. 2019); Endo Pharms. Inc. v. Teva Pharms. USA, Inc., 919 F.3d 1347, 1348 (Fed. Cir. 2019); Cellspin Soft, Inc. v. Fitbit, Inc., 927 F.3d 1306 (Fed. Cir. 2019); Aatrix Software, Inc. v. Green Shades Software, Inc., 882 F.3d 1121 (Fed. Cir. 2018); Berkheimer v. HP Inc., 881 F.3d 1360, 1363 (Fed. Cir. 2018); Vanda Pharms. Inc. v. W.-Ward Pharms. Int'l Ltd., 887 F.3d 1117 (Fed. Cir. 2018); Enfish, LLC v. Microsoft Corp., 822 F.3d 1327 (Fed. Cir. 2016); McRO, Inc. v. Bandai Namco Games Am. Inc., 837 F.3d 1299 (Fed. Cir. 2016); Ariosa Diagnostics, Inc. v. Sequenom, Inc., 788 F.3d 1371 (Fed. Cir. 2015); DDR Holdings, LLC v. Hotels.com, L.P., 773 F.3d 1245 (Fed. Cir. 2014).

279.

See infra "Legislative Developments" (reviewing congressional proposals to amend Section 101).

280. Notice, 2019 Revised Patent Subject Matter Eligibility Guidance, 84 Fed. Reg. 50 (Jan. 7, 2019) [hereinafter 2019 Notice, 2019 Revised Patent Subject Matter Eligibility Guidance, 84 Fed. Reg. 50 (Jan. 7, 2019) [hereinafter 2019
Guidance]. Guidance]. PTOUSPTO subsequently issued an update to this guidance in October 2019. subsequently issued an update to this guidance in October 2019. See U.S. U.S. PAT. & TRADEMARK OFFPat. & Trademark Off., .,
October 2019 Update: Subject Matter Eligibility (Oct. 2019), (Oct. 2019),
https://www.uspto.gov/sites/default/files/documents/peg_oct_2019_update.pdf [hereinafter the October 2019 Update]. https://www.uspto.gov/sites/default/files/documents/peg_oct_2019_update.pdf [hereinafter the October 2019 Update].
These guidance documents have been incorporated in the These guidance documents have been incorporated in the PTO’USPTO's Manual of Patent Examining Procedure. 281. See 2019 Guidance, supra note 280, at 50 ("s Manual of Patent Examining Procedure (MPEP). See
U.S. PATENT & TRADEMARK OFF., Subject Matter Eligibility, https://www.uspto.gov/patents/laws/examination-
policy/subject-matter-eligibility (last visited Nov. 19, 2022); U.S. PAT. & TRADEMARK OFF., MANUAL OF PATENT
EXAMINING PROCEDURE §§ 2103–2106 (last revised 2020), available at
https://www.uspto.gov/web/offices/pac/mpep/index.html [hereinafter MPEP].
277 See 2019 Guidance, supra note 276, at 50 (“The legal uncertainty surrounding Section 101 poses unique challenges The legal uncertainty surrounding Section 101 poses unique challenges
for the USPTO, which must ensure that its more than 8500 patent examiners and administrative patent judges apply the for the USPTO, which must ensure that its more than 8500 patent examiners and administrative patent judges apply the
Alice/Mayo test in a manner that produces reasonably consistent and predictable results across applications, art units test in a manner that produces reasonably consistent and predictable results across applications, art units
and technology fields.and technology fields.”"); ); see also U.S. U.S. PAT. & TRADEMARK OFFPat. & Trademark Off., ., U.S. Patent Statistics Chart Calendar Years 1963–
2015, https://www.uspto.gov/web/offices/ac/ido/oeip/taf/us_stat.htm (last visited , https://www.uspto.gov/web/offices/ac/ido/oeip/taf/us_stat.htm (last visited Nov. 21, 2022Mar. 5, 2025) (indicating that the ) (indicating that the
PTOUSPTO received 589,410 applications in 2015). received 589,410 applications in 2015).
278 See 2019 Guidance, note 276, at 50.
279 See MPEP §§ 2103–2106.
280 Id. at § 2106.04(a).
281 2019 Guidance, note 276, at 51.
282 Id. at 52.
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3) Mental processes – concepts performed in the human mind (including an observation,
evaluation, judgment, opinion.283
Under the Guidance, patent claims that do not recite matter that falls into one of these three
groupings should not be treated as an “abstract idea” except in “rare circumstance[s].”284
Second, the 2019 Guidance clarifies when examiners will treat a patent claim as “directed to” an
ineligible category (abstract ideas, laws of nature, or natural phenomena) under step one of the
Alice/Mayo test.285 In particular, the PTO will not treat a claim as “directed to” an ineligible
concept if “the claim as a whole integrates the recited judicial exception into a practical
application of the exception.”286 If the claim does integrate a practical application—such as
improving the functioning of a computer, effecting a particular treatment for a disease, or
implementing the exception into a particular machine or manufacture—then the PTO will treat
the claim as patent-eligible, without having to examine the patent application for an “inventive
concept” under step two of the Alice/Mayo framework.287
The 2019 Guidance was generally perceived as lowering Section 101 barriers to patentability,
especially for computer-related inventions.288 Some commentators praised the Guidance for
providing greater clarity to patent examiners, while other stakeholders criticized the Guidance as
inconsistent with the Supreme Court’s Section 101 decisions.289
Although the PTO’s 2019 Guidance changes how PTO examiners review new patent applications,
the Guidance is not binding on the courts when patents are challenged in litigation (unlike
decisions of appellate courts or statutes). The PTO lacks general substantive rulemaking
authority,290 and the Guidance itself states that it is only a “tool for internal [PTO] management”
that lacks “the force and effect of law.”291 Although the Federal Circuit has issued somewhat

283 MPEP § 2106.04(a) (internal cross-references omitted).
284 Id.
285 Id. at § 2106.04. The PTO calls the Alice/Mayo test’s first step “Step 2A” of its Section 101 examination process.
See id.
286 Id. at § 2106.04(d) (emphasis added).
287 Id. at §§ 2106, 2106.04(d).
288 See, e.g., James J. DeCarlo & George David Zalpea, The USPTO’ 282.

See 2019 Guidance, note 280, at 50.

283.

See U.S. Patent & Trademark Off., Subject Matter Eligibility, https://www.uspto.gov/patents/laws/examination-policy/subject-matter-eligibility (last visited Mar. 6, 2025); U.S. Pat. & Trademark Off., Manual of Patent Examining Procedure §§ 2103–2106 (last revised Jan. 2024), available at https://www.uspto.gov/web/offices/pac/mpep/index.html [hereinafter MPEP].

284.

Id. at § 2106.04(a).

285.

2019 Guidance, note 280, at 51.

286.

Id. at 52.

287.

MPEP § 2106.04(a) (internal cross-references omitted).

288.

Id.

289.

Id. at § 2106.04. The USPTO calls the Alice/Mayo test's first step "Step 2A" of its Section 101 examination process. See id.

290.

Id. at § 2106.04(d) (emphasis added).

291.

Id. at §§ 2106, 2106.04(d).

292. See, e.g., James J. DeCarlo & George David Zalpea, The USPTO's New § 101 Guidance: Progress or Pitfall?, N.J. Laws New § 101 Guidance: Progress or Pitfall?, N.J.
LAW J. (May 13, 2019), https://www. J. (May 13, 2019), https://www.law.com/njlawjournal/2019/05/10gtlaw.com/en/insights/2019/5/published-articles/the-usptos-new-/the-usptos-new-%C2%A7101101-guidance--guidance-
progress-or-pitfallprogress-or-pitfall/ ((“"In practice, many applicants are seeing a noticeable decrease of rejections under § 101 [after the In practice, many applicants are seeing a noticeable decrease of rejections under § 101 [after the
2019 Guidance.]2019 Guidance.]”"); Michelle Holoubeck & Lestin Kenton, ); Michelle Holoubeck & Lestin Kenton, 5 Things to Know About USPTO’'s New Eligibility
Guidance, , LAW360Law360 (Jan. 8, 2019) (Jan. 8, 2019), https://www.law360.com/articles/1116262/5-things-to-know-about-uspto-s-new-https://www.law360.com/articles/1116262/5-things-to-know-about-uspto-s-new-
eligibility-guidanceeligibility-guidance (" (“The [PTOThe [PTO’'s] new guidance eases the burden on patenting computer-implemented invention.s] new guidance eases the burden on patenting computer-implemented invention.”).
289"). 293. See generally Stuart P. Meyer, Stuart P. Meyer, No Shortage of Viewpoints on New USPTO Eligibility Guidelines, , BILSKI BLOG
Bilski Blog (Mar. 26, 2019), https://www.fenwick.com/bilski-blog/no-shortage-of-viewpoints-on-new-uspto-patent-eligibility-(Mar. 26, 2019), https://www.fenwick.com/bilski-blog/no-shortage-of-viewpoints-on-new-uspto-patent-eligibility-
guidelines (reviewing comments received by guidelines (reviewing comments received by PTOUSPTO on the 2019 Guidance and noting that on the 2019 Guidance and noting that “"both the both the ‘'new Guidance is new Guidance is
great’great' and the and the ‘'new Guidance doesnnew Guidance doesn’'t follow t follow Alice’' camps are very well represented camps are very well represented”).
290"). 294. Merck & Co. v. Kessler, 80 F.3d 1543, 1549–50 (Fed. Cir. 1996) (holding that while the Merck & Co. v. Kessler, 80 F.3d 1543, 1549–50 (Fed. Cir. 1996) (holding that while the PTOUSPTO may promulgate may promulgate
regulations directed to the conduct of its own proceedings, it lacks authority to regulations directed to the conduct of its own proceedings, it lacks authority to “"issue substantive rulesissue substantive rules”" under the under the
Patent Act); AssPatent Act); Ass’'n for Molecular Pathology v. n for Molecular Pathology v. U.S. PTOUSPTO, 689 F.3d 1303, 1357 (Fed. Cir. 2012) (Bryson, J., concurring , 689 F.3d 1303, 1357 (Fed. Cir. 2012) (Bryson, J., concurring
in part and dissenting in part) (in part and dissenting in part) (“"As we have recognized, the PTO lacks substantive rulemaking authority as to issues As we have recognized, the PTO lacks substantive rulemaking authority as to issues
such as patentability.such as patentability.”"); ); see generally Melissa F. Wasserman, Melissa F. Wasserman, The Changing Guard of Patent Law: Chevron Chevron Deference
for the PTO, 54 , 54 WM. & MARY L. REVWm. & Mary L. Rev. 1959, 1962 (2013) (. 1959, 1962 (2013) (“"[The [The PTOUSPTO] lacks robust substantive rule-making authority ] lacks robust substantive rule-making authority
and receives no judicial deference for its legal interpretations of the Patent Act.and receives no judicial deference for its legal interpretations of the Patent Act.”).
291 2019 Guidance, supra note 276, at 51.
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contradictory signals on this point,292 the Guidance would receive, at most, “some deference” if a
court found its reasoning to be persuasive.293
Following the 2019 Guidance, the PTO has continued efforts to increase clarity and consistency
in its Section 101 determinations.294 In 2020, the PTO Office of the Chief Economist issued a
report on patent examination outcomes following Alice.295 That study found that while Section
101 rejections in certain technological fields increased by 31% in the 18 months after Alice, the
rejection rate decreased by 35% after issuance of the 2019 Guidance, with less variability in
outcomes across examiners.296 In response to a 2021 letter from Senators Tillis and Cotton,297 the
PTO launched the Deferred Subject Matter Eligibility Response Pilot Program, which invites
selected patent applicants to defer consideration of subject-matter eligibility issues until other
patentability issues (such as those under Sections 102, 103, and 112) are resolved.298
In 2022, at the urging of a bipartisan group of Senators,299 the PTO solicited public comment and
published a report for Congress summarizing stakeholder views on current patent-eligible subject
matter law.300 While the report found a consensus that patent-eligibility law should be “clear,
predictable, and consistently applied,” stakeholders differed on whether current Section 101 law
achieved that ideal.301 Finding a “continuing divide” on the issue, the PTO report indicated that
defenders of the Alice/Mayo framework (primarily from the computer technology industry) found

292"). 295.

2019 Guidance, supra note 280, at 51.

296. Compare Nat. Alternatives IntNat. Alternatives Int’'l, Inc. v. Creative Compounds, LLC, 918 F.3d 1338, 1346 n.2 (Fed. Cir. 2019) l, Inc. v. Creative Compounds, LLC, 918 F.3d 1338, 1346 n.2 (Fed. Cir. 2019)
(noting that (noting that “"[t]he parties dispute the persuasiveness of this document and the weight we should afford it under [t]he parties dispute the persuasiveness of this document and the weight we should afford it under
[[Skidmore],],”" but declining to decide whether the 2019 Guidance should receive any deference), but declining to decide whether the 2019 Guidance should receive any deference), with Cleveland Clinic Cleveland Clinic
Found. v. True Health Diagnostics LLC, 760 F. AppFound. v. True Health Diagnostics LLC, 760 F. App’'x 1013, 1020 (Fed. Cir. 2019) (x 1013, 1020 (Fed. Cir. 2019) (“"While we greatly respect the While we greatly respect the
PTO’PTO's expertise on all matters relating to patentability, including patent eligibility, we are not bound by its guidance.s expertise on all matters relating to patentability, including patent eligibility, we are not bound by its guidance.”"). ).
See generally Andrew Michaels, Andrew Michaels, How Much Deference Courts Owe to USPTO Guidance, , LAW360Law360 (June 20, 2019), (June 20, 2019),
https://www.law360.com/ip/articles/1171217/how-much-deference-courts-owe-to-uspto-guidancehttps://www.law360.com/ip/articles/1171217/how-much-deference-courts-owe-to-uspto-guidance.
293. 297. See Loper Bright Enters. v. Raimondo, No. 22-451, slip op. at 23 (U.S. June 28, 2024); United States v. Mead Corp., 533 U.S. 218, 234 (2001) ( United States v. Mead Corp., 533 U.S. 218, 234 (2001) (“"[A]n agency[A]n agency’'s interpretation [of a statute] may merit some s interpretation [of a statute] may merit some
deference whatever its form, given the specialized experience and broader investigations and information available to deference whatever its form, given the specialized experience and broader investigations and information available to
the agency, and given the value of uniformity in its administrative and judicial understandings of what a national law the agency, and given the value of uniformity in its administrative and judicial understandings of what a national law
requires.requires.”") (citations omitted); Skidmore v. Swift & Co., 323 U.S. 134, 140 (1944) () (citations omitted); Skidmore v. Swift & Co., 323 U.S. 134, 140 (1944) (“"The weight of [an informal The weight of [an informal
agency] judgment in a particular case will depend upon the thoroughness evident in its consideration, the validity of its agency] judgment in a particular case will depend upon the thoroughness evident in its consideration, the validity of its
reasoning, its consistency with earlier and later pronouncements, and all those factors which give it power to persuade, reasoning, its consistency with earlier and later pronouncements, and all those factors which give it power to persuade,
if lacking power to control.if lacking power to control.”).
294"). 298. See generally Kathy Vidal, Kathy Vidal, Director of the PTO, Providing Clear Guidance on Patent Subject Matter Eligibility,
U.S. PAT. & TRADEMARK OFFEligibility, U.S. Pat. & Trademark Off. (July 25, 2022), https://www.uspto.gov/blog/director/entry/providing-clear-guidance-on-. (July 25, 2022), https://www.uspto.gov/blog/director/entry/providing-clear-guidance-on-
patent.
295 ANDREW A. TOOLE & NICHOLAS A. PAIROLERO, ADJUSTING TO ALICEpatent. 299. Andrew A. Toole & Nicholas A. Pairolero, Adjusting to Alice (U.S. Pat. & Trademark Off. April 2020), (U.S. Pat. & Trademark Off. April 2020),
https://www.uspto.gov/sites/default/files/documents/OCE-DH_AdjustingtoAlice.pdfhttps://www.uspto.gov/sites/default/files/documents/OCE-DH_AdjustingtoAlice.pdf.
296 Id. at 1.
297. 300.

Id. at 1.

301. Letter from Sens. Thom Tillis and Tom Cotton to Drew Hirschfeld Letter from Sens. Thom Tillis and Tom Cotton to Drew Hirschfeld, Acting PTO Director (Mar. 22, 2021), (Mar. 22, 2021),
https://www.uspto.gov/sites/default/files/documents/sens-sequencedexam-20210322.pdfhttps://www.uspto.gov/sites/default/files/documents/sens-sequencedexam-20210322.pdf.
298 PTO. 302. USPTO, Deferred Subject Matter Eligibility Response Pilot Program, 87 Fed. Reg. 776 (Jan. 6, 2022). This pilot , Deferred Subject Matter Eligibility Response Pilot Program, 87 Fed. Reg. 776 (Jan. 6, 2022). This pilot
program is program is “"designed to evaluate how deferred applicant responses to subject matter eligibility (SME) rejections affect designed to evaluate how deferred applicant responses to subject matter eligibility (SME) rejections affect
examination efficiency and patent quality.examination efficiency and patent quality.”" U.S. U.S. PAT. & TRADEMARK OFFICEPat. & Trademark Office, , Deferred Subject Matter Eligibility
Eligibility Response (DSMER) Pilot Program, Program, https://www.uspto.gov/patents/initiatives/patent-application-initiatives/deferred-https://www.uspto.gov/patents/initiatives/patent-application-initiatives/deferred-
subject-matter-eligibility-response (last visited subject-matter-eligibility-response (last visited Nov. 22, 2022).
299Mar. 31, 2025). 303. See Letter from Sens. Thom Tillis, Mazie Hirono, Tom Cotton and Christopher Coons to Drew Hirschfeld Letter from Sens. Thom Tillis, Mazie Hirono, Tom Cotton and Christopher Coons to Drew Hirschfeld, Acting
PTO Director (Mar. 5, 2021), https://www.tillis.senate.gov/services/files/04D9DCF2-B699-41AC-BE62- (Mar. 5, 2021), https://www.tillis.senate.gov/services/files/04D9DCF2-B699-41AC-BE62-
9DCA9460EDDA.
300 U.S. PAT. & TRADEMARK OFF., PATENT ELIGIBLE SUBJECT MATTER: PUBLIC VIEWS ON THE CURRENT JURISPRUDENCE
IN THE UNITED STATES9DCA9460EDDA. 304. U.S. Pat. & Trademark Off., Patent Eligible Subject Matter: Public Views on the Current Jurisprudence in the United States (June 2022), https://www.uspto.gov/sites/default/files/documents/USPTO- (June 2022), https://www.uspto.gov/sites/default/files/documents/USPTO-
SubjectMatterEligibility-PublicViews.pdfSubjectMatterEligibility-PublicViews.pdf.
301 Id. at ii, 41.
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current law to be sufficiently clear and an important tool for addressing overbroad patents and
abusive lawsuits.302 On the other side, critics of the Alice/Mayo framework (especially life-
science industries) found the current law to be unpredictable and to have detrimental effects on
innovation and investment in the development of new technologies.303
Legislative Developments in the 116th Congress
The First Tillis-Coons Proposal
In the 116th Congress, Senators Tillis and Coons, along with Representatives Collins, Johnson,
and Stivers, released a “bipartisan, bicameral framework” for legislative Section 101 reform (the
First Tillis-Coons Proposal).304 The framework’s release followed multiple roundtables with
patent law stakeholders on Section 101 and the effect of the Alice/Mayo framework on, for
example, innovation in artificial intelligence, medical diagnostics, and personalized medicine.305
The First Tillis-Coons Proposal would have retained the four current statutory categories of
patentable inventions, but removed the requirement that the invention or discovery be “new and
useful” from Section 101.306 Patent eligibility would have instead been determined “by
considering each and every element of the claim as a whole and without regard for considerations
properly addressed by [Sections] 102, 103 and 112 [of the Patent Act].”307
In place of the judicially created exceptions to patent eligibility, which the First Tillis-Coons
Proposal would have abrogated by statute, the proposal listed five “exclusive” categories of
patent-ineligible subject matter: (1) fundamental scientific principles; (2) products that exist
solely and exclusively in nature; (3) pure mathematical formulas; (4) economic or commercial
principles; and (5) mental activities.308 Effectively, this would have codified aspects of the
judicial exceptions in a narrower form, with the first two ineligible categories roughly
corresponding to the “law of nature” and “natural product” judicial exceptions, and the final three
to the types of “abstract ideas” identified by the PTO in its 2019 Guidance.309 The Proposal would
have narrowed the construction of these ineligible categories by creating a “practical application”
test,310 akin to the ABA proposal, expressly permitting patenting of a practical application of
ineligible subject matter.311 But “simply reciting generic technical language or generic functional
language” would have been insufficient to “salvage an otherwise ineligible claim.”312

302 Id. at 41.
303 Id.
304 See Sen. Tillis April 17 Press Release, supra note 29.
305 Id.; see generally “The Debate Over Alice/Mayo and Section 101 Reform.”
306 First Tillis-Coons Proposal, supra note 29.
307 Id.
308 Id.
309 See Phillip M. Nelson & Bridget A. Smith, Legislators Propose “Section 101 Reform,” KNOBBE MARTENS (Apr. 18,
2019), https://www.knobbe.com/news/2019/04/legislators-propose-%E2%80%9Csection-101-reform%E2%80%9D
(“[The First Tillis-Coons Proposal] would codify several of the judicial exceptions. The last three categories correspond
to those enumerated in the USPTO’s recent guidance.”).
310 First Tillis-Coons Proposal, supra note 29.
311 See supra note 257 and accompanying text.
312 First Tillis-Coons Proposal, supra note 29.
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The First Tillis-Coons Proposal thus blended elements of the PTO’s 2019 Guidance with a
“laundry list” approach of specific ineligible categories, plus new statutory standards for how to
apply the list of exceptions to patentable subject matter.313 The overall effect would be to lower
Section 101 barriers to patentability, while still retaining more narrowly defined classes of
ineligible subject matter.314
Reactions to the First Tillis-Coons Proposal were mixed.315 Some commentators argued that the
draft proposal was a promising start for much-needed congressional intervention.316 Indeed, some
critics of the Alice/Mayo framework argued that the First Tillis-Coons Proposal did not go far
enough, and urged elimination of any ineligible categories of patentable subject matter.317 On the
pro-Alice side of the debate, the Electronic Frontier Foundation, for example, criticized the First
Tillis-Coons Proposal as detrimental to innovation because it would eliminate a powerful tool to
combat bad patents and patent troll litigation.318
The Second Tillis-Coons Proposal
Following feedback on their first draft framework, the same group of Members released a “draft
bill” to reform Section 101 (the Second Tillis-Coons Proposal).319 The Second Tillis-Coons
Proposal was released before a series of three hearings held in the 116th Congress before the
Senate Judiciary Committee’s Subcommittee on Intellectual Property, which solicited feedback
on the draft legislative language.320 In these hearings, 45 witnesses testified over three days, with
representatives from industry, academia, bar associations, and trade groups; former Federal
Circuit Judges and PTO officers; and other patent law stakeholders expressing various views on
Section 101 reform.321

313 See supra “Specific Statutory List of Included or Excluded Subject Matter Categories”; “Administrative
Developments: PTO Subject Matter Eligibility Guidance”; see also Nelson & Smith, supra note 309 (“ [hereinafter 2022 Public Views Report]. 305.

Id. at ii, 41.

306.

Id. at 41.

307.

Id.

308.

See USTPO, Off. of the Chief Economist, Inventing AI: Tracing the Diffusion of Artificial Intelligence with U.S. Patents (Oct. 2020), at 3, https://www.uspto.gov/sites/default/files/documents/OCE-DH-AI.pdf.

309.

See 2022 Public Views Report, supra note 304, at 8.

310.

USPTO, 2024 Guidance Update on Patent Subject Matter Eligibility, Including on Artificial Intelligence, 89 Fed. Reg. 58,128 (July 17, 2024) [hereinafter 2024 AI Eligibility Guidance]. Another CRS product reviews USPTO's 2024 AI Eligibility Guidance in more detail. See generally CRS Legal Sidebar LSB11251, Artificial Intelligence and Patent Law, by Kevin J. Hickey and Christopher T. Zirpoli (2024).

311.

See MPEP § 2106.05

312.

2024 AI Eligibility Guidance, 89 Fed. Reg. at 58,134–38.

313.

See USPTO, July 2024 Subject Matter Eligibility Examples, https://www.uspto.gov/sites/default/files/documents/2024-AI-SMEUpdateExamples47-49.pdf (last visited Mar. 11, 2025), at 5.

314.

Id. at 18–21.

315.

Id. at 21–24.

316.

See, e.g., PhRMA, Comments of the Pharmaceutical Research and Manufacturers of America in Response to the USPTO's 2024 Guidance Update on Patent Subject Matter Eligibility, Including on Artificial Intelligence (Oct. 16, 2024), https://www.regulations.gov/comment/PTO-P-2024-0026-0018 ("PhRMA appreciates USPTO's efforts to streamline interpretation of [patent-eligible subject matter] jurisprudence and application to pending matters before the Office so as to create a more predictable landscape for patent applicant.").

317.

See, e.g., Eileen McDermott & Steve Brachmann, IP Organizations Want More on USPTO's AI Patent Eligibility Guidance, IPWatchDog, https://ipwatchdog.com/2024/10/20/ip-organizations-want-usptos-ai-patent-eligibility-guidance/id=182378/ (Oct. 20, 2024) (summarizing public comments on the 2024 AI Eligibility Guidance).

318.

H.R. 5874, 117th Cong. (2021).

319.

See, e.g., id. §§ 4–5 (abolishing the PTAB and the IPR/PGR procedures).

320.

Id. § 7(b).

321.

Id. § 7(a).

322.

Id.

323.

Id.

324.

See Press Release, Office of Sen. Thom Tillis, Sens. Tillis and Coons and Reps. Collins, Johnson, and Stivers Release Section 101 Patent Reform Framework (Apr. 17, 2019), https://www.tillis.senate.gov/2019/4/sens-tillis-and-coons-and-reps-collins-johnson-and-stivers-release-section-101-patent-reform-framework [hereinafter Sen. Tillis April 17 Press Release]; Sen. Tillis et al., Draft Outline for Section 101 Reform, https://www.tillis.senate.gov/services/files/3491a23f-09c3-4f4a-9a93-71292704c5b1 [hereinafter First Tillis-Coons Proposal].

325. Id.; see generally "The Debate Over Alice/Mayo and Section 101 Reform." 326.

See First Tillis-Coons Proposal, supra note 324.

327.

Id.

328.

Id.

329.

See Phillip M. Nelson & Bridget A. Smith, Legislators Propose "Section 101 Reform," Knobbe Martens (Apr. 18, 2019), https://www.knobbe.com/blog/legislators-propose-section-101-reform/ ("[The First Tillis-Coons Proposal] would codify several of the judicial exceptions. The last three categories correspond to those enumerated in the USPTO's recent guidance.").

330. See supra "Specific Statutory List of Included or Excluded Subject Matter Categories"; "Administrative Developments in the USPTO "; see also Nelson & Smith, supra note 329 ("[The First Tillis-[The First Tillis-
Coons Proposal] includes some aspects of the proposals from several patent specialty associations, including those Coons Proposal] includes some aspects of the proposals from several patent specialty associations, including those
from the AIPLA/IPO, IPLAC, and the ABA-IPL section.from the AIPLA/IPO, IPLAC, and the ABA-IPL section.”).
314"). 331. See Daniel T. Taskalos, Daniel T. Taskalos, Returning to the Status Quo?—Proposed Outline for Section 101 Reform, , NAT’L L. REV.
Nat'l L. Rev. (Apr. 22, 2019), https://www.natlawreview.com/article/returning-to-status-quo-proposed-outline-section-101-reform(Apr. 22, 2019), https://www.natlawreview.com/article/returning-to-status-quo-proposed-outline-section-101-reform
(“ ("In all, the proposed framework appears to focus on returning the 101 analysis to its previous status as more of a low In all, the proposed framework appears to focus on returning the 101 analysis to its previous status as more of a low
hurdle to patentability, but a hurdle nonetheless.hurdle to patentability, but a hurdle nonetheless.”).
315"). 332. See generally Eileen McDermott, Eileen McDermott, Reactions Roll in on Congress’'s Proposed 101 Framework: ‘'The Right Approach’
or ‘' or 'a Swing and a Miss”?, IPWATCHDOG"?, IPWatchdog (Apr. 18, 2019), https://www.ipwatchdog.com/2019/04/18/reactions-roll-in- (Apr. 18, 2019), https://www.ipwatchdog.com/2019/04/18/reactions-roll-in-
on-congresss-proposed-101-framework-the-right-approach-or-a-swing-and-a-miss/id=108407/ (surveying positive and on-congresss-proposed-101-framework-the-right-approach-or-a-swing-and-a-miss/id=108407/ (surveying positive and
negative reactions to the First Tillis-Coons Proposal).negative reactions to the First Tillis-Coons Proposal).
316 333. See, e.g., Antoinette F. Konski, , Antoinette F. Konski, Is 101 Relief in Sight?, Foley & Lardner?, FOLEY & LARDNER LLP (Apr. 17, 2019), LLP (Apr. 17, 2019),
https://www.foley.com/en/insights/publications/2019/04/is-101-relief-in-sight (calling the First Tillis-Coons Proposal https://www.foley.com/en/insights/publications/2019/04/is-101-relief-in-sight (calling the First Tillis-Coons Proposal
“"a step in the right directiona step in the right direction”"); McDermott, ); McDermott, supra note 315 note 332 (quoting stakeholder comment that the First Tillis-Coons (quoting stakeholder comment that the First Tillis-Coons
Proposal is Proposal is “"exactly the right approachexactly the right approach”" to bring predictability to Section 101). to bring predictability to Section 101).
317 334. See, e.g., Mark Marrello, , Mark Marrello, Urge the Drafters of the New Section 101 to Support Inventor-Friendly Reform, ,
IPWATCHDOGIPWatchdog (May 13, 2019), https://www.ipwatchdog.com/2019/05/13/urge-drafters-new-section-101-support- (May 13, 2019), https://www.ipwatchdog.com/2019/05/13/urge-drafters-new-section-101-support-
inventor-friendly-reform/id=109206/inventor-friendly-reform/id=109206/.
318. 335. Alex Moss, Alex Moss, The Tillis-Coons Patent Bill Will Be a Disaster for Innovation, , ELECTRONIC FRONTIER FOUNDElectronic Frontier Found. (Apr. 24, . (Apr. 24,
2019), https://www.eff.org/deeplinks/2019/04/tillis-coons-patent-bill-will-be-disaster-innovation2019), https://www.eff.org/deeplinks/2019/04/tillis-coons-patent-bill-will-be-disaster-innovation.
319 See Sen. Tillis May 22 Press Release, supra note 30.
320 Id.
321 See generally Coons & Tillis, supra note 31.. 336.

See Press Release, Office of Sen. Thom Tillis, Sens. Tillis and Coons and Reps. Collins, Johnson, and Stivers Release Draft Bill Text to Reform Section 101 of the Patent Act (May 22, 2019), https://www.tillis.senate.gov/2019/5/sens-tillis-and-coons-and-reps-collins-johnson-and-stivers-release-draft-bill-text-to-reform-section-101-of-the-patent-act.

337.

Id.

338. See generally Coons & Tillis, supra note 29. For a succinct summary of the main views expressed at the hearings, For a succinct summary of the main views expressed at the hearings,
see Bruce M. Wexler et al., see Bruce M. Wexler et al., Senate Hearing on “"The State of Patent Eligibility in America”": Analysis of Viewpoints on
Looming Section 101 Change, , PAUL HASTINGSPaul Hastings (June 25, 2019), https://www.paulhastings.com/publications- (June 25, 2019), https://www.paulhastings.com/publications-
items/details/?id=c58c536d-2334-6428-811c-ff00004cbdedlitems/details/?id=c58c536d-2334-6428-811c-ff00004cbdedl. For a more detailed witness-by-witness breakdown, see Stuart M. Meyer, Still No Shortage of Viewpoints as Eligibility Debate Moves to the Hill, Bilski Blog (June 27, 2019), https://www.fenwick.com/bilski-blog/still-no-shortage-of-viewpoints-as-eligibility-debate-moves-to-the-hill. 339.

See Sen. Tillis et al., Draft Bill for Section 101 Reform, https://www.tillis.senate.gov/services/files/E8ED2188-DC15-4876-8F51-A03CF4A63E26 (proposed § 101(a)–(b) and "Additional Legislative Provisions") [hereinafter Second Tillis-Coons Proposal].

340.

Id. ("Additional Legislative Provisions").

341.

Id.

342.

Id.

343.

See supra "Historical Development of the Judicial Exceptions to Patent-Eligible Subject Matter."

344.

See supra "Replace Judicial Exceptions with a Different Standard"; "Section 101: Utility."

345.

See Second Tillis-Coons Proposal, supra note 339 (proposed § 101(a)).

346.

See id. (proposed § 100(k)). The draft bill did not further define "practical utility," "field of technology," or "human intervention."

347. See Coons & Tillis, supra note 29 (indicating that the Section 112(f) amendments were intended "to guard against . . . overly broad, functional patent claims"); see generally "Section 112(f): Functional Claiming". For a more detailed witness-by-witness breakdown, see
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As compared with the first proposal, the Second Tillis-Coons Proposal would have made more
sweeping changes to Section 101 to expand patent eligibility. Like the First Tillis-Coons
Proposal, the draft bill had several provisions that attempted to separate the Section 101 inquiry
from other patentability requirements. Specifically, the draft bill would have struck the word
“new” from Section 101 and established that patent subject matter eligibility must be determined
“considering the claimed invention as a whole” and without regard to “considerations relating to
section 102, 103, or 112 of [the Patent Act].”322 The Second Tillis-Coons Proposal provided that
eligibility determinations would not depend on the “manner in which the claimed invention was
made; whether individual limitations of a claim are well known, conventional or routine; [or] the
state of the art at the time of the invention.”323 The draft bill also explicitly provided that Section
101 “shall be construed in favor of eligibility.”324
Rather than narrow the judicial exceptions to patentability, the Second Tillis-Coons Proposal
would have eliminated those exceptions altogether. The draft bill provided that
No implicit or other judicially created exceptions to subject matter eligibility, including
“abstract ideas,” “laws of nature,” or “natural phenomena,” shall be used to determine
patent eligibility under section 101, and all cases establishing or interpreting those
exceptions to eligibility are hereby abrogated.325
This language would have overturned by statute not only the Alice/Mayo framework, but over
two centuries of judicial decisions interpreting the “common law” exceptions to Section 101.326
The Second Tillis-Coons Proposal would have replaced the judicial exceptions with a new
statutory definition of utility that incorporated elements of various prior proposals for a new
Section 101 standard.327 To be patent-eligible subject matter under the Second Tillis-Coons
Proposal, the invention would need to fit into one of the four statutory categories of eligible
subject matter (which remain unchanged) and be “useful.”328 To be “useful,” an invention or
discovery would need to provide “specific and practical utility in any field of technology through
human intervention.”329
Finally, to combat overbroad patent claims, the Second Tillis-Coons Proposal would have altered
the functional claiming rules under Section 112(f), which permits patentees to claim their
invention in functional terms as opposed to reciting specific physical structures.330 In particular,
the draft bill provided that if any patent claim element is “expressed as a specified function
without the recital of structure, material, or acts in support thereof,” then that claim element will
be limited to the “corresponding structure, material, or acts described in the specification” and

Stuart M. Meyer, Still No Shortage of Viewpoints as Eligibility Debate Moves to the Hill, BILSKI BLOG (June 27, 2019),
https://www.fenwick.com/bilski-blog/still-no-shortage-of-viewpoints-as-eligibility-debate-moves-to-the-hill.
322 See Second Tillis-Coons Proposal, supra note 30 (proposed § 101(a)–(b) and “Additional Legislative Provisions”).
323 Id. (“Additional Legislative Provisions”).
324 Id.
325 Id.
326 See supra “Historical Development of the Judicial Exceptions to Patent-Eligible Subject Matter.”
327 See supra “Replace Judicial Exceptions with a Different Standard”; “Section 101: Utility.”
328 See Second Tillis-Coons Proposal, supra note 30 (proposed § 101(a)).
329 See id. (proposed § 100(k)). The draft bill did not further define “practical utility,” “field of technology,” or “human
intervention.”
330 See Coons & Tillis, supra note 31 (indicating that the Section 112(f) amendments were intended “to guard against
. . . overly broad, functional patent claims”); see generally “Section 112(f): Functional Claiming” (summarizing current (summarizing current
law of functional claiming).law of functional claiming).
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their equivalents.331 Consistent with decisions of the Federal Circuit,332 this language would have
clarified that Section 112(f) applies to any claim element that fails to sufficiently recite a structure
for performing a function.333 This change could have arguably made it tougher for a patentee to
avoid the limiting effects of Section 112(f), even if the words “means for” are not used in the
claim language.334
As with the first proposal, reactions to the Second Tillis-Coons Proposal from patent law
stakeholders were mixed.335 Critics of the Alice/Mayo framework generally applauded the draft
bill as bringing much needed clarity and certainty to the law of patent eligibility,336 particularly
for biotechnology innovation.337 Opponents of the draft bill expressed concern that changes to the
Alice/Mayo framework would eliminate an important tool against unmeritorious patent
litigation.338 Critics also questioned the necessity and advisability of such a sweeping change to
Section 101 law.339 Both supporters and opponents raised concerns about potential ambiguities in
the proposed definition of “useful,” particularly the terms “human intervention,” “practical
utility,” and “field of technology.”340

331 Second Tillis-Coons Proposal, supra note 30 (proposed § 112(f)).
332 348. Williamson v. Citrix Online, LLC, 792 F.3d 1339 (Fed. Cir. 2015) (en banc). Williamson v. Citrix Online, LLC, 792 F.3d 1339 (Fed. Cir. 2015) (en banc).
333 349. Compare Second Tillis-Coons Proposal, Second Tillis-Coons Proposal, supra note 30 note 339 (proposed § 112(f)), (proposed § 112(f)), with 35 U.S.C. § 112(f). 35 U.S.C. § 112(f). See also Patent
Eligibility Hearings, , supra note 31 (statementnote 29 (statement of Christopher A. Mohr, Vice President for Intellectual Property and of Christopher A. Mohr, Vice President for Intellectual Property and
General Counsel, Software and Information Industry Association), at 11, General Counsel, Software and Information Industry Association), at 11,
https://www.judiciary.senate.gov/download/mohr-testimonyhttps://www.judiciary.senate.gov/download/mohr-testimony (" (“[The proposed § 112(f) language appears to do little [The proposed § 112(f) language appears to do little
more than cement the Federal Circuitmore than cement the Federal Circuit’'s s Williamson v. Citrix decision . . . . decision . . . .”).
334"). 350. See Patent Eligibility Hearings, , supra note 31 note 29 (statement of David W. Jones, Executive Director, High Tech (statement of David W. Jones, Executive Director, High Tech
Inventors Alliance), at 12, https://www.judiciary.senate.gov/download/06/05/2019/jones-testimony [hereinafter Jones Inventors Alliance), at 12, https://www.judiciary.senate.gov/download/06/05/2019/jones-testimony [hereinafter Jones
Testimony] (Testimony] (“"[The proposed Section 112(f)] amendment represents a modest improvement over the current language [The proposed Section 112(f)] amendment represents a modest improvement over the current language
and will eliminate lingering arguments about the effect of inclusion or omission of the words and will eliminate lingering arguments about the effect of inclusion or omission of the words ‘'means formeans for’' and whether and whether
particular terms should be interpreted as functional in the wake of [particular terms should be interpreted as functional in the wake of [Williamson v. Citrix].].”).
335"). 351. See generally Wexler et al., Wexler et al., supra note 321 (summarizingnote 338 (summarizing arguments made by supporters and opponents of the arguments made by supporters and opponents of the
Second Tillis-Coons Proposal).Second Tillis-Coons Proposal).
336 352. See, e.g., , Patent Eligibility Hearings, , supra note 31 (statementnote 29 (statement of Judge Paul R. Michel (Ret.), U.S. Court of of Judge Paul R. Michel (Ret.), U.S. Court of
Appeals for the Federal Circuit), at 1, https://www.judiciary.senate.gov/download/michel-testimony (praising the Appeals for the Federal Circuit), at 1, https://www.judiciary.senate.gov/download/michel-testimony (praising the
Second Tillis-Coons Proposal as Second Tillis-Coons Proposal as “"a very good starting point [that] represents an enormous improvement over the a very good starting point [that] represents an enormous improvement over the
present, intolerable chaos [in Section 101 law]present, intolerable chaos [in Section 101 law]”"); ); Patent Eligibility Hearings, , supra note 31 (statementnote 29 (statement of Q. Todd of Q. Todd
Dickinson, former Director of the Dickinson, former Director of the PTOUSPTO), at 36, https://www.judiciary.senate.gov/download/dickinson-testimony), at 36, https://www.judiciary.senate.gov/download/dickinson-testimony
[hereinafter Dickinson Testimony] (expressing [hereinafter Dickinson Testimony] (expressing “"general support for this positive proposal that should go far in general support for this positive proposal that should go far in
clarifying and resolving several major issues . . . particularly the interpretation and use of § 101 . . . .clarifying and resolving several major issues . . . particularly the interpretation and use of § 101 . . . .”).
337"). 353. See, e.g., , Patent Eligibility Hearings, , supra note 31 (statementnote 29 (statement of Laurie Hill, Vice President, Intellectual Property, of Laurie Hill, Vice President, Intellectual Property,
Genentech, Inc.), at 8, 15–16, https://www.judiciary.senate.gov/download/hill-testimony (supporting the Second Tillis-Genentech, Inc.), at 8, 15–16, https://www.judiciary.senate.gov/download/hill-testimony (supporting the Second Tillis-
Coons Proposal as Coons Proposal as “"a strong step in the right directiona strong step in the right direction”" because of the because of the “"present uncertainty surrounding Section 101 present uncertainty surrounding Section 101
[that] threatens to disrupt the development of a wide range of important medicines, diagnostics, treatments, and other [that] threatens to disrupt the development of a wide range of important medicines, diagnostics, treatments, and other
innovations that benefit societyinnovations that benefit society”).
338"). 354. See, e.g., Gugliuzza Testimony, , Gugliuzza Testimony, supra note 236,note 237, at 6–7 (arguing that at 6–7 (arguing that “"completely dismantling the eligibility completely dismantling the eligibility
requirement would take away a crucial tool courts can use to end, at relatively low cost, patent cases that plainly lack requirement would take away a crucial tool courts can use to end, at relatively low cost, patent cases that plainly lack
merit.merit.”).
339"). 355. See, e.g., Jones Testimony, , Jones Testimony, supra note 334,note 350, at 7 ( at 7 (“"The evidence and arguments that have been advanced by The evidence and arguments that have been advanced by
proponents [of Section 101 reform] simply do not provide any reasonable justification for . . . the complete abrogation proponents [of Section 101 reform] simply do not provide any reasonable justification for . . . the complete abrogation
of two centuries of eligibility case law.of two centuries of eligibility case law.”).
340"). 356. See, e.g., Dickinson Testimony, , Dickinson Testimony, supra note 336,note 352, at 33–34; Jones Testimony, at 33–34; Jones Testimony, supra note 334,note 350, at 10–11. at 10–11.
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Stakeholders also debated the specific practical effects of the legislative changes at the hearings,
such as the effect of elimination of the judicial exceptions on basic scientific research.341 One
concern, raised by the American Civil Liberties Union in opposition to the draft bill, was that the
Second Tillis-Coons Proposal, by abrogating the Myriad decision,342 would permit the patenting
of human genes.343 Several witnesses denied that the draft bill would lead to that result because of
the bill’s “human intervention” requirement or other patent law principles.344 For their part,
Senators Tillis and Coons made clear that they had “no intention” of overruling the result in
Myriad that no one may patent “genes as they exist in the human body.”345 Senators Tillis and
Coons stated that the hearings in the 116th Congress reinforced their view that “patent eligibility
is broken and desperately needs to be repaired,” and that there is a “necessity for Congress to
intervene” to bring greater clarity to Section 101.346 Ultimately, the Members did not formally
introduce a Section 101 reform bill during the 116th Congress.
Legislative Developments in the 117th Congress
The 117th Congress to date has seen two introduced bills proposing reforms to Section 101, one
in the Senate and one in the House.
The Patent Eligibility Restoration Act of 2022
In the Senate, Senator Tillis introduced S. 4734, the Patent Eligibility Restoration Act of 2022
(PERA). PERA would retain the four statutory categories of eligible subject matter, but delete the
word “new” in Section 101 and add a new definition of “useful.”347 PERA’s utility definition
would require that “the invention or discovery has a specific and practical utility from the
perspective of a person of ordinary skill in the art.”348 Moreover, PERA would change the
definition of “process” to clarify that “a use, application, or method of manufacture of a known or
naturally-occurring process” is patentable.349 PERA would also establish that patent eligibility
determinations shall be made without regard to “any consideration in [35 U.S.C.] section 102,
103, or 112” including “whether a claim element is known, conventional, routine, or naturally
occurring.”350

341 357. See, e.g., , Patent Eligibility Hearings, , supra note 31 (statementnote 29 (statement of Charles Duan, Director, Technology & Innovation of Charles Duan, Director, Technology & Innovation
Policy, R Street Institute), at 13–18, https://www.judiciary.senate.gov/download/duan-testimonyPolicy, R Street Institute), at 13–18, https://www.judiciary.senate.gov/download/duan-testimony.
342. 358. See supra notes 170–174 See supra notes 169–173 and accompanying text (discussing the Supreme Courtand accompanying text (discussing the Supreme Court’'s decision in s decision in Association for
Molecular Pathology v. Myriad Genetics, Inc.). 359. .).
343 See, e.g., , Patent Eligibility Hearings, , supra note 31 (statementnote 29 (statement of Kate Ruane, Senior Legislative Counsel, of Kate Ruane, Senior Legislative Counsel,
Washington Legislative Office, ACLU) at 3, https://www.judiciary.senate.gov/download/ruane-testimony (arguing that Washington Legislative Office, ACLU) at 3, https://www.judiciary.senate.gov/download/ruane-testimony (arguing that
the Second Tillis-Coons Proposal the Second Tillis-Coons Proposal “"would clearly make human genes, isolated from the rest of the genome, patent-would clearly make human genes, isolated from the rest of the genome, patent-
eligible againeligible again”"). 360. ).
344 See, e.g., , Patent Eligibility Hearings, , supra note 31 (statementnote 29 (statement of Corey Salsberg, Vice President and Global Head of Corey Salsberg, Vice President and Global Head
Intellectual Property Affairs for Novartis), at 6, https://www.judiciary.senate.gov/download/salsberg-testimony; Intellectual Property Affairs for Novartis), at 6, https://www.judiciary.senate.gov/download/salsberg-testimony; Patent
Eligibility Hearings, , supra note 31 (statementnote 29 (statement of Philip S. Johnson, Chair, Coalition for 21st Century Patent Reform), of Philip S. Johnson, Chair, Coalition for 21st Century Patent Reform),
at 8, https://www.judiciary.senate.gov/download/06/05/2019/johnson-testimonyat 8, https://www.judiciary.senate.gov/download/06/05/2019/johnson-testimony. 361. .
345 Sen. Chris Coons & Sen. Thom Tillis, Sen. Chris Coons & Sen. Thom Tillis, It’'s Time to Restore America’'s Patent System, , THE HILLThe Hill (June 10, 2019), (June 10, 2019),
https://thehill.com/blogs/congress-blog/technology/447666-its-time-to-restore-americas-patent-systemhttps://thehill.com/blogs/congress-blog/technology/447666-its-time-to-restore-americas-patent-system.
346 Coons & Tillis, supra note 31.
347 S. 4734, 117th Cong. § 2.
348 Id. § 2(a)(1)(B).
349 Id. § 2(a)(1)(A).
350 Id. § 2(a)(2).
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Like the First Tillis-Coons proposal in the 116th Congress, PERA contains a closed list of the
types of inventions that are not patent-eligible when claimed “as such,” specifically:
(A) A mathematical formula, apart from a useful invention or discovery.
(B) A process that—
(i) is a non-technological economic, financial, business, social, cultural, or artistic
process;
(ii) is a mental process performed solely in the human mind; or
(iii) occurs in nature wholly independent of, and prior to, any human activity.
(C) An unmodified human gene, as that gene exists in the human body.
(D) An unmodified natural material, as that material exists in nature.
In effect, PERA would abrogate the Alice/Mayo framework, and replace the three judicially
created ineligible categories with this closed statutory list of narrower ineligible categories.351
The Restoring America’s Leadership in Innovation Act of 2021
In the House, Representative Massie introduced H.R. 5874, the Restoring America’s Leadership
in Innovation Act of 2021 (RALIA).352 Alongside provisions designed to reverse many of the
changes in patent law enacted through the 2011 America Invents Act,353 Section 7 of RALIA
responds to the Supreme Court’s Section 101 decisions. Expressing the view that the Court’s
recent Section 101 jurisprudence “has harmed the progress of science and the useful arts,” the bill
would “effectively abrogate[]” those decisions (specifically, Bilski, Mayo, Alice, Myriad, “and
[their] predecessors”).354
To “ensure that life sciences discoveries, computer software, and similar inventions and
discoveries are patentable,” RALIA would replace the three judicially created exceptions to
patent-eligible subject matter with a single, relatively narrow statutory exception. Under RALIA,
any new and useful process, machine, manufacture, or composition of matter is patent-eligible
unless “the claimed invention as a whole, as understood by a person having ordinary skill in the
art, exists in nature independently of and prior to any human activity, or exists solely in the
human mind.”355 RALIA would therefore generally expand the types of inventions that are
patentable even further than PERA would. Like PERA, RALIA abrogates the Alice/Mayo
framework and provides that eligibility determinations under Section 101 shall be made “without
regard as to the requirements or conditions of sections 102, 103, and 112 of this title, or the
claimed invention’s inventive concept.”356
Conclusion
The Supreme Court’s 2010s decisions on patent-eligible subject matter have inspired a robust
debate among patent law stakeholders as to whether the Court’s jurisprudence in this area
advances or harms innovation. Recent actions by the courts, the PTO, and Congress have

351 See id. (providing that the four statutorily eligible categories would be “subject only to the [listed] exclusions”).
352 H.R. 5874, 117th Cong. (2021).
353 See, e.g., id. at §§ 4–5 (abolishing the PTAB and the IPR/PGR procedures).
354 Id. at § 7(b).
355 Id. at § 7(a).
356 Id.
Congressional Research Service
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Patent-Eligible Subject Matter Reform

responded to the Court’s decisions in various ways, including proposed statutory changes
discussed in the 116th Congress and introduced in the 117th Congress.

Author Information

Kevin J. Hickey

Legislative Attorney



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Congressional Research Service
R45918 · VERSION 3 · UPDATED
41
. 362.

H.R. 5874, 117th Cong. § 7.

363.

S. 4734, 117th Cong. § 2.

364.

Id. § 2(a)(1)(B).

365.

Id. § 2(a)(1)(A).

366.

Id. § 2(a)(2).

367.

Id. For the ineligible "non-technological" processes, PERA 2022 further provided that they would have been eligible if the process was meaningfully "embodied in a machine or manufacture." Id. PERA 2022 also explained that a human gene or natural material would have been considered "modified" (and thus patent-eligible) if it was "isolated, purified, enriched, or otherwise altered by human activity." Id.

368.

See id. (providing that the four statutorily eligible categories would be "subject only to the [listed] exclusions").

369.

Restoring America's Leadership in Innovation Act of 2024, H.R. 8134, 118th Cong., § 7 (2024).

370.

Patent Eligibility Restoration Act of 2023, S. 2140, 118th Cong. (2023).

371.

Id. § 2.

372.

Id. § 3(a).

373.

Id. § 3(a)(2).

374.

Compare id. with S. 4734, 117th Cong. § 2(a)(2). Like PERA 2022, PERA 2023 made clear that—contrary to the result in the Myriad case—isolation, purification, or other human alteration sufficed to make natural material and human genes "modified" and therefore patent eligible. See S. 2140, 118th Cong. § 3(a)(2).

375.

See S. 4734, 117th Cong. § 2(a)(2).

376.

See S. 2140, 118th Cong. § 3(a)(2) (emphasis added).

377.

Id.

378.

H.R. 9474, Patent Eligibility Restoration Act of 2024, 118th Cong. (2024).

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