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Section 101 of U.S. patent law (35 U.S.C. §101) provides that:

Whoever invents or discovers any new and useful process, machine, manufacture, or composition of matter, or any new and useful improvement thereof, may obtain a patent therefor, subject to the conditions and requirements of this title.

Process, machine, manufacture, composition of matter and new and useful improvements constitute the categories of patentable subject matter. The latter three categories define "things" or "products" while the first category defines "actions" (i.e., inventions that consist of a series of steps or acts to be performed).[1] Section 101 defines in “expansive terms” the categories of patent-eligible inventions.[2] Thomas Jefferson, an author of the Act of Feb. 21, 1793 (1793 Patent Act),[3] desired that “ingenuity should receive a liberal encouragement,” and broad and flexible patent laws are integral to that goal.[4] Consistent with that intent, “[t]he subject-matter provisions of the patent law have been cast in broad terms to fulfill the constitutional and statutory goal of promoting ‘the Progress of Science and the useful Arts’ with all that means for the social and economic benefits envisioned by Jefferson.”[5]

Whether a claim is drawn to patent-eligible subject matter under §101 is a threshold inquiry, and any claim of an application failing the requirements of §101 must be rejected, even if it meets all of the other legal requirements of patentability.[6] Whether a claim is drawn to patent-eligible subject matter under §101 is an issue of law that we review de novo.[7] Claim construction, which the court reviews de novo, is an important first step in a §101 analysis.[8]

Limitations on patentability[]

“Broad,” however, does not mean unbounded. Although the prospect of patent protection may create incentives for research and innovation that would not otherwise occur, the restrictions imposed by the patent laws entail social costs as well. For instance, patent protection may have the effect of excluding would-be competitors who could produce a patented invention more efficiently, thereby inhibiting post-invention competition and innovation. The Patent Act therefore “reflects a balance between the need to encourage innovation and the avoidance of monopolies which stifle competition without any concomitant advance in the ‘Progress of Science and useful Arts.’”[9]

Federal courts have held that 35 U.S.C. §101 does have certain limits. First, the phrase "anything under the sun that is made by man" is limited by the text of 35 U.S.C. §101, meaning that one may only patent something that is a machine, manufacture, composition of matter or a process.[10] Second, 35 U.S.C. §101 requires that the subject matter sought to be patented be a "new and useful" invention. Accordingly, a complete definition of the scope of 35 U.S.C. §101, reflecting congressional intent, is that any new and useful process, machine, manufacture or composition of matter under the sun that is made by man is the proper subject matter of a patent.

Section 101 reflects Congress’s determination that, for specified categories of subject matter (processes, machines, manufactures, and compositions of matter), the goal of fostering innovation may justify the restrictions on post-invention competition that the patent laws impose. Section 101 also makes clear, however, that inventions falling outside those broad but bounded categories are ineligible for patent protection even if they satisfy the Patent Act’s other requirements. “[N]o patent is available for a discovery, however useful, novel, and nonobvious, unless it falls within one of the express categories of patentable subject matter of 35 U.S.C. § 101.”[11] By “bring[ing] certain types of invention and discovery within the scope of patentability while excluding others,” the Patent Act of 1952 “seeks to avoid the dangers of overprotection just as surely as it seeks to avoid the diminished incentive to invent that underprotection can threaten.”[12] In this important respect, the patent laws “determine not only what is protected, but also what is free for all to use.”[13]

In applying Section 101 and its predecessors to specific inventions, the Court has provided a concrete definition for each of the four statutory categories.[14]

Excluded subject matter[]

Despite this broad mandate, courts have long held certain types of inventions unpatentable. Traditional common law exceptions include phenomena of nature, abstract intellectual concepts, mental steps, mathematical algorithms with no substantial practical application, printed matter, and, for many years, business methods.

The relevant principle of law "exclude[s] from ... patent protection ... laws of nature, natural phenomena, and abstract ideas." Diamond v. Diehr, 450 U.S. 175, 185 (1981). This principle finds its roots in both English and American law.... The principle means that Einstein could not have "patented his celebrated law that E mc2; nor could Newton have patented the law of gravity." Diamond v. Chakrabarty, 447 U.S. 303, 309 (1980). Neither can one patent "a novel and useful mathematical formula." Parker v. Flook, 437 U.S. 584, 585 (1978), the motive power of electromagnetism or steam. Morse, supra, at 116, "the heat of the sun, electricity, or the qualities of metals." Funk Brothers Seed Co. v. Kalo Inoculant Co., 333 U.S. 127, 130 (1948).

The justification for the principle does not lie in any claim that "laws of nature" are obvious, or that their discovery is easy, or that they are not useful. To the contrary, research into such matters may be costly and time-consuming; monetary incentives may matter; and the fruits of those incentives and that research may prove of great benefit to the human race. Rather, the reason for the exclusion is that sometimes too much patent protection can impede rather than "promote the Progress of Science and useful Arts," the constitutional objective of patent and copyright protection. U.S. Const., Art. I, §8, cl. 8.

Patent law seeks to avoid the dangers of overprotection just as surely as it seeks to avoid the diminished incentive to invent that underprotection can threaten. One way in which patent law seeks to sail between these opposing and risky shoals is through rules that bring certain types of invention and discovery within the scope of patentability while excluding others.[15]

Determining whether an applicant is seeking to patent an abstract idea, a law of nature or a natural phenomenon has proven to be challenging. These three exclusions recognize that subject matter that is not a practical application or use of an idea, a law of nature or a natural phenomenon is not patentable.[16]

The courts have also held that a claim may not preempt an idea, law of nature or natural phenomena. The concern over preemption was expressed as early as 1852.[17] Accordingly, one may not patent every "substantial practical application" of an idea, law of nature or natural phenomena because such a patent would "in practical effect be a patent on the [idea, law of nature or natural phenomena] itself."[18]

Over the past twenty-five years, however, the scope of patentable subject matter has expanded significantly. For example, the Supreme Court, through two landmark decisions in 1980, held that both man-made, living organisms[19] and computer software constitute patentable subject matter pursuant to Section 101. In 1999, the Federal Circuit ruled that business methods can be patented.

Utility patents[]

Patents under Section 101 are known as utility patents, and are divided for examination purposes into three classes by the U.S. Patent and Trademark Office (PTO): chemical, electrical, and mechanical. Patents for software-related inventions are classified within the electrical class, relating to data processing methods and apparatus.


  1. See 35 U.S.C. §100(b) ("The term 'process' means process, art, or method, and includes a new use of a known process, machine, manufacture, composition of matter, or material.").
  2. Diamond v. Chakrabarty, 447 U.S. 303, 308 (1980).
  3. ch. 11, 1 Stat. 318.
  4. See Chakrabarty, 447 U.S. at 308-309 (quoting 5 Writings of Thomas Jefferson 75-76 (Washington ed. 1871)).
  5. Id. at 315; see J.E.M. Ag Supply, Inc. v. Pioneer Hi-Bred Int’l, Inc., 534 U.S. 124, 130 (2001) (“In choosing such expansive terms as ‘manufacture’ and ‘composition of matter,’ modified by the comprehensive ‘any,’ Congress plainly contemplated that the patent laws would be given wide scope.”) (quoting Chakrabarty, 447 U.S. at 308).
  6. In re Comiskey, 499 F.3d 1365, 1371 (Fed. Cir. 2007) (quoting Parker v. Flook, 437 U.S. 584, 593 (1978)); In re Bergy, 596 F.2d 952, 960 (C.C.P.A. 1979), vacated as moot sub nom. Diamond v. Chakrabarty, 444 U.S. 1028 (1980).
  7. Comiskey, 499 F.3d at 1373; AT&T Corp. v. Excel Commns., Inc., 172 F.3d 1352, 1355 (Fed. Cir. 1998).
  8. State St. Bank & Trust Co. v. Signature Fin. Group, 149 F.3d 1368, 1370 (Fed. Cir. 1998).
  9. Bonito Boats, Inc. v. Thunder Craft Boats, Inc., 489 U.S. 141, 146 (1989).
  10. See, e.g., In re Alappat, 33 F.3d 1526, 1542, 31 U.S.P.Q.2d (BNA) 1545, 1556 (Fed. Cir. 1994) (en banc); In re Warmerdam, 33 F.3d 1354, 1358, 31 U.S.P.Q.2d (BNA) 1754, 1757 (Fed. Cir. 1994).
  11. Kewanee Oil Co. v. Bicron Corp., 416 U.S. 470, 483 (1974).
  12. Laboratory Corp. of America Holdings v. Metabolite Labs., Inc., 548 U.S. 124, 127 (2006) (LabCorp) (Breyer, J., dissenting from dismissal of a writ of certiorari).
  13. Bonito Boats, 489 U.S. at 151.
  14. See, e.g., Diamond v. Diehr, 450 U.S. 175, 184 (1981) (“Transformation and reduction of an article ‘to a different state or thing’ is the clue to the patentability of a process claim that does not include particular machines.”)(quoting Gottschalk v. Benson, 409 U.S. 63, 70 (1972), and Cochrane v. Deener, 94 U.S. 780, 787-788 (1877)); Corning v. Burden, 56 U.S. (15 How.) 252, 267 (1854) (“The term machine includes every mechanical device or combination of mechanical powers and devices to perform some function and produce a certain effect or result.”); American Fruit Growers, Inc. v. Brogdex Co., 283 U.S. 1, 11 (1931) (“manufacture” means “anything made for use from raw or prepared materials,” including by “giving to these materials new forms, qualities, properties, or combinations, whether by hand-labor or by machinery”); Chakrabarty, 447 U.S. at 308 (“composition of matter” means “all compositions of two or more substances and . . . all composite articles, whether they be the results of chemical union, or of mechanical mixture, or whether they be gases, fluids, powders or solids”) (quoting Shell Dev. Co. v. Watson, 149 F. Supp. 279, 280 (D.D.C. 1957), aff’d, 252 F.2d 861 (D.C. Cir. 1958) (citing 1 Anthony William Deller, Walker on Patents § 14, at 55 (1937))).
  15. Lab. Corp. of America v. Metabolite Labs, Inc., 126 S. Ct. 2921 (2006).
  16. See, e.g., Rubber-Tip Pencil Co. v. Howard, 87 U.S. (20 Wall.) 498, 507 (1874) ("idea of itself is not patentable, but a new device by which it may be made practically useful is"); Mackay Radio & Telegraph Co. v. Radio Corp. of America, 306 U.S. 86, 94, 40 U.S.P.Q. (BNA) 199, 202 (1939) ("While a scientific truth, or the mathematical expression of it, is not patentable invention, a novel and useful structure created with the aid of knowledge of scientific truth may be."); Warmerdam, 33 F.3d at 1360, 31 U.S.P.Q.2d (BNA) at 1759 ("steps of 'locating' a medial axis, and 'creating' a bubble hierarchy . . . describe nothing more than the manipulation of basic mathematical constructs, the paradigmatic 'abstract idea'").
  17. See LeRoy v. Tatham, 55 U.S. 156, 175 (1852) ("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."); Funk Brothers Seed Co. v. Kalo Inoculant Co., 333 U.S. 127, 132, 76 U.S.P.Q. (BNA) 280, 282 (1948) (combination of six species of bacteria held to be nonstatutory subject matter).
  18. Gottschalk v. Benson, 409 U.S. 63, 71-72, 175 U.S.P.Q. (BNA) 673, 676 (1972).
  19. Diamond v. Chakrabarty, 447 U.S. 303 (1980).