450 U.S. 175 (1981)

DIAMOND, COMMISSIONER OF PATENTS AND TRADEMARKS
v.
DIEHR ET AL.

No. 79-1112.

Supreme Court of United States.

Argued October 14, 1980. Decided March 3, 1981. CERTIORARI TO THE UNITED STATES COURT OF CUSTOMS AND PATENT APPEALS.

*176 Deputy Solicitor General Wallace argued the cause for petitioner. With him on the briefs were Solicitor General McCree, Assistant Attorney General Litvack, Harriet S. Shapiro, Robert B. Nicholson, Frederic Freilicher, Joseph F. Nakamura, and Thomas E. Lynch.

Robert E. Wichersham argued the cause for respondents. With him on the brief were Robert F. Hess, Jay M. Cantor, and Thomas M. Freiburger.^[*]

*177 JUSTICE REHNQUIST delivered the opinion of the Court.

We granted certiorari to determine whether a process for curing synthetic rubber which includes in several of its steps the use of a mathematical formula and a programmed digital computer is patentable subject matter under 35 U. S. C. § 101.

I

The patent application at issue was filed by the respondents on August 6, 1975. The claimed invention is a process for molding raw, uncured synthetic rubber into cured precision products. The process uses a mold for precisely shaping the uncured material under heat and pressure and then curing the synthetic rubber in the mold so that the product will retain its shape and be functionally operative after the molding is completed.^[1]

Respondents claim that their process ensures the production of molded articles which are properly cured. Achieving the perfect cure depends upon several factors including the thickness of the article to be molded, the temperature of the molding process, and the amount of time that the article is allowed to remain in the press. It is possible using well-known time, temperature, and cure relationships to calculate by means of the Arrhenius equation^[2] when to open the press *178 and remove the cured product. Nonetheless, according to the respondents, the industry has not been able to obtain uniformly accurate cures because the temperature of the molding press could not be precisely measured, thus making it difficult to do the necessary computations to determine cure time.^[3] Because the temperature inside the press has heretofore been viewed as an uncontrollable variable, the conventional industry practice has been to calculate the cure time as the shortest time in which all parts of the product will definitely be cured, assuming a reasonable amount of mold-opening time during loading and unloading. But the shortcoming of this practice is that operating with an uncontrollable variable inevitably led in some instances to overestimating the mold-opening time and overcuring the rubber, and in other instances to underestimating that time and undercuring the product.^[4]

Respondents characterize their contribution to the art to reside in the process of constantly measuring the actual temperature inside the mold. These temperature measurements are then automatically fed into a computer which repeatedly recalculates the cure time by use of the Arrhenius equation. *179 When the recalculated time equals the actual time that has elapsed since the press was closed, the computer signals a device to open the press. According to the respondents, the continuous measuring of the temperature inside the mold cavity, the feeding of this information to a digital computer which constantly recalculates the cure time, and the signaling by the computer to open the press, are all new in the art.

The patent examiner rejected the respondents' claims on the sole ground that they were drawn to nonstatutory subject matter under 35 U. S. C. § 101.^[5] He determined that those *180 steps in respondents' claims that are carried out by a computer under control of a stored program constituted nonstatutory subject matter under this Court's decision in Gottschalk v. Benson, 409 U. S. 63 (1972). The remaining steps—installing rubber in the press and the subsequent closing of the *181 press—were "conventional and necessary to the process and cannot be the basis of patentability." The examiner concluded that respondents' claims defined and sought protection of a computer program for operating a rubber-molding press.

The Patent and Trademark Office Board of Appeals agreed with the examiner, but the Court of Customs and Patent Appeals reversed. In re Diehr, 602 F. 2d 892 (1979). The court noted that a claim drawn to subject matter otherwise statutory does not become nonstatutory because a computer is involved. The respondents' claims were not directed to a mathematical algorithm or an improved method of calculation but rather recited an improved process for molding rubber articles by solving a practical problem which had arisen in the molding of rubber products.

The Commissioner of Patents and Trademarks sought certiorari arguing that the decision of the Court of Customs and Patent Appeals was inconsistent with prior decisions of this Court. Because of the importance of the question presented, we granted the writ. 445 U. S. 926 (1980).

II

Last Term in Diamond v. Chakrabarty, 447 U. S. 303 (1980), this Court discussed the historical purposes of the patent laws and in particular 35 U. S. C. § 101. As in Chakrabarty, we must here construe 35 U. S. C. § 101 which provides:

"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."^[6]

*182 In cases of statutory construction, we begin with the language of the statute. Unless otherwise defined, "words will be interpreted as taking their ordinary, contemporary, common meaning," Perrin v. United States, 444 U. S. 37, 42 (1979), and, in dealing with the patent laws, we have more than once cautioned that "courts `should not read into the patent laws limitations and conditions which the legislature has not expressed.'" Diamond v. Chakrabarty, supra, at 308, quoting United States v. Dubilier Condenser Corp., 289 U. S. 178, 199 (1933).

The Patent Act of 1793 defined statutory subject matter as "any new and useful art, machine, manufacture or composition of matter, or any new or useful improvement [thereof]." Act of Feb. 21, 1793, ch. 11, § 1, 1 Stat. 318. Not until the patent laws were recodified in 1952 did Congress replace the word "art" with the word "process." It is that latter word which we confront today, and in order to determine its meaning we may not be unmindful of the Committee Reports accompanying the 1952 Act which inform us that Congress intended statutory subject matter to "include anything under the sun that is made by man." S. Rep. No. 1979, 82d Cong., 2d Sess., 5 (1952); H. R. Rep. No. 1923, 82d Cong., 2d Sess., 6 (1952).

Although the term "process" was not added to 35 U. S. C. § 101 until 1952, a process has historically enjoyed patent protection because it was considered a form of "art" as that term was used in the 1793 Act.^[7] In defining the nature of a patentable process, the Court stated:

"That a process may be patentable, irrespective of the *183 particular form of the instrumentalities used, cannot be disputed. . . . A process is 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. If new and useful, it is just as patentable as is a piece of machinery. In the language of the patent law, it is an art. The machinery pointed out as suitable to perform the process may or may not be new or patentable; whilst the process itself may be altogether new, and produce an entirely new result. The process requires *184 that certain things should be done with certain substances, and in a certain order; but the tools to be used in doing this may be of secondary consequence." Cochrane v. Deener, 94 U. S. 780, 787-788 (1877).

Analysis of the eligibility of a claim of patent protection for a "process" did not change with the addition of that term to § 101. Recently, in Gottschalk v. Benson, 409 U. S. 63 (1972), we repeated the above definition recited in Cochrane v. Deener, adding: "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." 409 U. S., at 70.

Analyzing respondents' claims according to the above statements from our cases, we think that a physical and chemical process for molding precision synthetic rubber products falls within the § 101 categories of possibly patentable subject matter. That respondents' claims involve the transformation of an article, in this case raw, uncured synthetic rubber, into a different state or thing cannot be disputed. The respondents' claims describe in detail a step-by-step method for accomplishing such, beginning with the loading of a mold with raw, uncured rubber and ending with the eventual opening of the press at the conclusion of the cure. Industrial processes such as this are the types which have historically been eligible to receive the protection of our patent laws.^[8]

*185 III

Our conclusion regarding respondents' claims is not altered by the fact that in several steps of the process a mathematical equation and a programmed digital computer are used. This Court has undoubtedly recognized limits to § 101 and every discovery is not embraced within the statutory terms. Excluded from such patent protection are laws of nature, natural phenomena, and abstract ideas. See Parker v. Flook, 437 U. S. 584 (1978); Gottschalk v. Benson, supra, at 67; Funk Bros. Seed Co. v. Kalo Inoculant Co., 333 U. S. 127, 130 (1948). "An idea of itself is not patentable," Rubber-Tip Pencil Co. v. Howard, 20 Wall. 498, 507 (1874). "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." Le Roy v. Tatham, 14 How. 156, 175 (1853). Only last Term, we explained:

"[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=mc[2]; nor could Newton have patented the law of gravity. Such discoveries are `manifestations of . . . nature, free to all men and reserved exclusively to none.'" Diamond v. Chakrabarty, 447 U. S., at 309, quoting Funk Bros. Seed Co. v. Kalo Inoculant Co., supra, at 130.

Our recent holdings in Gottschalk v. Benson, supra, and Parker v. Flook, supra, both of which are computer-related, stand for no more than these long-established principles. In Benson, we held unpatentable claims for an algorithm used to convert binary code decimal numbers to equivalent pure binary numbers. The sole practical application of the algorithm was in connection with the programming of a *186 general purpose digital computer. We defined "algorithm" as a "procedure for solving a given type of mathematical problem," and we concluded that such an algorithm, or mathematical formula, is like a law of nature, which cannot be the subject of a patent.^[9]

Parker v. Flook, supra, presented a similar situation. The claims were drawn to a method for computing an "alarm limit." An "alarm limit" is simply a number and the Court concluded that the application sought to protect a formula for computing this number. Using this formula, the updated alarm limit could be calculated if several other variables were known. The application, however, did not purport to explain how these other variables were to be determined,^[10] nor *187 did it purport "to contain any disclosure relating to the chemical processes at work, the monitoring of process variables, or the means of setting off an alarm or adjusting an alarm system. All that it provides is a formula for computing an updated alarm limit." 437 U. S., at 586.

In contrast, the respondents here do not seek to patent a mathematical formula. Instead, they seek patent protection for a process of curing synthetic rubber. Their process admittedly employs a well-known mathematical equation, but they do not seek to pre-empt the use of that equation. Rather, they seek only to foreclose from others the use of that equation in conjunction with all of the other steps in their claimed process. These include installing rubber in a press, closing the mold, constantly determining the temperature of the mold, constantly recalculating the appropriate cure time through the use of the formula and a digital computer, and automatically opening the press at the proper time. Obviously, one does not need a "computer" to cure natural or synthetic rubber, but if the computer use incorporated in the process patent significantly lessens the possibility of "overcuring" or "undercuring," the process as a whole does not thereby become unpatentable subject matter.

Our earlier opinions lend support to our present conclusion that a claim drawn to subject matter otherwise statutory does not become nonstatutory simply because it uses a mathematical formula, computer program, or digital computer. In Gottschalk v. Benson we noted: "It is said that the decision precludes a patent for any program servicing a computer. We do not so hold." 409 U. S., at 71. Similarly, in Parker v. Flook we stated that "a process is not unpatentable simply because it contains a law of nature or a mathematical algorithm." 437 U. S., at 590. It is now commonplace that an application of a law of nature or mathematical formula to a known structure or process may well be deserving of patent protection. See, e. g., Funk Bros. Seed *188 Co. v. Kalo Inoculant Co., 333 U. S. 127 (1948); Eibel Process Co. v. Minnesota & Ontario Paper Co., 261 U. S. 45 (1923); Cochrane v. Deener, 94 U. S. 780 (1877); O'Reilly v. Morse, 15 How. 62 (1854); and Le Roy v. Tatham, 14 How. 156 (1853). As Justice Stone explained four decades ago:

"While a scientific truth, or the mathematical expression of it, is not a patentable invention, a novel and useful structure created with the aid of knowledge of scientific truth may be." Mackay Radio & Telegraph Co. v. Radio Corp. of America, 306 U. S. 86, 94 (1939).^[11]

We think this statement in Mackay takes us a long way toward the correct answer in this case. Arrhenius' equation is not patentable in isolation, but when a process for curing rubber is devised which incorporates in it a more efficient solution of the equation, that process is at the very least not barred at the threshold by § 101.

In determining the eligibility of respondents' claimed process for patent protection under § 101, their claims must be considered as a whole. It is inappropriate to dissect the claims into old and new elements and then to ignore the presence of the old elements in the analysis. This is particularly true in a process claim because a new combination of steps in a process may be patentable even though all the constituents of the combination were well known and in common use before the combination was made. The "novelty" of any element or steps in a process, or even of the *189 process itself, is of no relevance in determining whether the subject matter of a claim falls within the § 101 categories of possibly patentable subject matter.^[12]

It has been urged that novelty is an appropriate consideration under § 101. Presumably, this argument results from the language in § 101 referring to any "new and useful" process, machine, etc. Section 101, however, is a general statement of the type of subject matter that is eligible for patent protection "subject to the conditions and requirements of this title." Specific conditions for patentability follow and § 102 covers in detail the conditions relating to novelty.^[13]*190 The question therefore of whether a particular invention is novel is "wholly apart from whether the invention falls into a category of statutory subject matter." In re Bergy, 596 F. 2d 952, 961 (CCPA 1979) (emphasis deleted). See also Nickola v. Peterson, 580 F. 2d 898 (CA6 1978). The legislative history of the 1952 Patent Act is in accord with this reasoning. The Senate Report stated:

"Section 101 sets forth the subject matter that can be patented, `subject to the conditions and requirements of this title.' The conditions under which a patent may be obtained follow, and Section 102 covers the conditions relating to novelty." S. Rep. No. 1979, 82d Cong., 2d Sess., 5 (1952) (emphasis supplied).

It is later stated in the same Report:

"Section 102, in general, may be said to describe the statutory novelty required for patentability, and includes, *191 in effect, an amplification and definition of `new' in section 101." Id., at 6.

Finally, it is stated in the "Revision Notes":

"The corresponding section of [the] existing statute is split into two sections, section 101 relating to the subject matter for which patents may be obtained, and section 102 defining statutory novelty and stating other conditions for patentability." Id., at 17.

See also H. R. Rep. No. 1923, 82d Cong., 2d Sess., 6, 7, and 17 (1952).

In this case, it may later be determined that the respondents' process is not deserving of patent protection because it fails to satisfy the statutory conditions of novelty under § 102 or nonobviousness under § 103. A rejection on either of these grounds does not affect the determination that respondents' claims recited subject matter which was eligible for patent protection under § 101.

IV

We have before us today only the question of whether respondents' claims fall within the § 101 categories of possibly patentable subject matter. We view respondents' claims as nothing more than a process for molding rubber products and not as an attempt to patent a mathematical formula. We recognize, of course, that when a claim recites a mathematical formula (or scientific principle or phenomenon of nature), an inquiry must be made into whether the claim is seeking patent protection for that formula in the abstract. A mathematical formula as such is not accorded the protection of our patent laws, Gottschalk v. Benson, 409 U. S. 63 (1972), and this principle cannot be circumvented by attempting to limit the use of the formula to a particular technological environment. Parker v. Flook, 437 U. S. 584 (1978). Similarly, insignificant postsolution activity will not transform *192 an unpatentable principle into a patentable process. Ibid.^[14] To hold otherwise would allow a competent draftsman to evade the recognized limitations on the type of subject matter eligible for patent protection. On the other hand, when a claim containing a mathematical formula implements or applies that formula in a structure or process which, when considered as a whole, is performing a function which the patent laws were designed to protect (e. g., transforming or reducing an article to a different state or thing), then the claim satisfies the requirements of § 101. Because we do not view respondents' claims as an attempt to patent a mathematical formula, but rather to be drawn to an industrial process *193 for the molding of rubber products, we affirm the judgment of the Court of Customs and Patent Appeals.^[15]

It is so ordered.

JUSTICE STEVENS, with whom JUSTICE BRENNAN, JUSTICE MARSHALL, and JUSTICE BLACKMUN join, dissenting.

The starting point in the proper adjudication of patent litigation is an understanding of what the inventor claims *194 to have discovered. The Court's decision in this case rests on a misreading of the Diehr and Lutton patent application. Moreover, the Court has compounded its error by ignoring the critical distinction between the character of the subject matter that the inventor claims to be novel—the § 101 issue— and the question whether that subject matter is in fact novel—the § 102 issue.

I

Before discussing the major flaws in the Court's opinion, a word of history may be helpful. As the Court recognized in Parker v. Flook, 437 U. S. 584, 595 (1978), the computer industry is relatively young. Although computer technology seems commonplace today, the first digital computer capable of utilizing stored programs was developed less than 30 years ago.^[1] Patent law developments in response to this new technology are of even more recent vintage. The subject of legal protection for computer programs did not begin to receive serious consideration until over a decade after completion of the first programmable digital computer.^[2] It was 1968 before *195 the federal courts squarely addressed the subject,^[3] and 1972 before this Court announced its first decision in the area.^[4]

Prior to 1968, well-established principles of patent law probably would have prevented the issuance of a valid patent on almost any conceivable computer program. Under the "mental steps" doctrine, processes involving mental operations were considered unpatentable. See, e. g., In re Heritage, 32 C. C. P. A. (Pat.) 1170, 1173-1177, 150 F. 2d 554, 556-558 (1945); In re Shao Wen Yuan, 38 C. C. P. A. (Pat.) 967, 972-976, 188 F. 2d 377, 380-383 (1951). The mental-steps doctrine was based upon the familiar principle that a scientific concept or mere idea cannot be the subject of a valid patent. See In re Bolongaro, 20 C. C. P. A. (Pat.) 845, 846-847, 62 F. 2d 1059, 1060 (1933).^[5] The doctrine was regularly invoked to deny patents to inventions consisting primarily of mathematical formulae or methods of computation.^[6] It was also applied against patent claims in which a mental operation or mathematical computation was the sole novel element or inventive contribution; it was clear that patentability *196 could not be predicated upon a mental step.^[7] Under the "function of a machine" doctrine, a process which amounted to nothing more than a description of the function of a machine was unpatentable. This doctrine had its origin in several 19th-century decisions of this Court,^[8] and it had been consistently followed thereafter by the lower federal courts.^[9]*197 Finally, the definition of "process" announced by this Court in Cochrane v. Deener, 94 U. S. 780, 787-788 (1877), seemed to indicate that a patentable process must cause a physical transformation in the materials to which the process is applied. See ante, at 182-184.

Concern with the patent system's ability to deal with rapidly changing technology in the computer and other fields led to the formation in 1965 of the President's Commission on the Patent System. After studying the question of computer program patentability, the Commission recommended that computer programs be expressly excluded from the coverage of the patent laws; this recommendation was based primarily upon the Patent Office's inability to deal with the administrative burden of examining program applications.^[10] At approximately the time that the Commission issued its report, the Patent Office published notice of its intention to prescribe guidelines for the examination of applications for patents on computer programs. See 829 Off. Gaz. Pat. Off. 865 (Aug. 16, 1966). Under the proposed guidelines, a computer program, whether claimed as an apparatus or as a process, was unpatentable.^[11] The Patent Office indicated, however, *198 that a programmed computer could be a component of a patentable process if combined with unobvious elements to produce a physical result. The Patent Office formally adopted the guidelines in 1968. See 33 Fed. Reg. 15609 (1968).

The new guidelines were to have a short life. Beginning with two decisions in 1968, a dramatic change in the law as understood by the Court of Customs and Patent Appeals took place. By repudiating the well-settled "function of a machine" and "mental steps" doctrines, that court reinterpreted § 101 of the Patent Code to enlarge drastically the categories of patentable subject matter. This reinterpretation would lead to the conclusion that computer programs were within the categories of inventions to which Congress intended to extend patent protection.

In In re Tarczy-Hornoch, 55 C. C. P. A. (Pat.) 1441, 397 F. 2d 856 (1968), a divided Court of Customs and Patent Appeals overruled the line of cases developing and applying the "function of a machine" doctrine. The majority acknowledged that the doctrine had originated with decisions of this Court and that the lower federal courts, including the Court of Customs and Patent Appeals, had consistently adhered to it during the preceding 70 years. Nonetheless, the court concluded that the doctrine rested on a misinterpretation of the precedents and that it was contrary to "the basic purposes of the patent system and productive of a range of undesirable results from the harshly inequitable to the silly." Id., at 1454, 397 F. 2d, at 867.^[12] Shortly thereafter, a similar *199 fate befell the "mental steps" doctrine. In In re Prater, 56 C. C. P. A. (Pat.) 1360, 415 F. 2d 1378 (1968), modified on rehearing, 56 C. C. A. P. (Pat.) 1381, 415 F. 2d 1393 (1969), the court found that the precedents on which that doctrine was based either were poorly reasoned or had been misinterpreted over the years. 56 C. C. P. A. (Pat.), at 1366-1372, 415 F. 2d, at 1382-1387. The court concluded that the fact that a process may be performed mentally should not foreclose patentability if the claims reveal that the process also may be performed without mental operations. Id., at 1374-1375, 415 F. 2d, at 1389.^[13] This aspect of the original Prater opinion was substantially undisturbed by the opinion issued after rehearing. However, the second Prater opinion clearly indicated that patent claims broad enough to encompass the operation of a programmed computer would not be rejected for lack of patentable subject matter. 56 C. C. P. A. (Pat.), at 1394, n. 29, 415 F. 2d, at 1403, n. 29.^[14]

*200 The Court of Customs and Patent Appeals soon replaced the overruled doctrines with more expansive principles formulated with computer technology in mind. In In re Bernhart, 57 C. C. P. A. (Pat.) 737, 417 F. 2d 1395 (1969), the court reaffirmed Prater, and indicated that all that remained of the mental-steps doctrine was a prohibition on the granting of a patent that would confer a monopoly on all uses of a scientific principle or mathematical equation. Id., at 743, 417 F. 2d, at 1399. The court also announced that a computer programmed with a new and unobvious program was physically different from the same computer without that program; the programmed computer was a new machine or at least a new improvement over the unprogrammed computer. Id., at 744, 417 F. 2d, at 1400. Therefore, patent protection could be obtained for new computer programs if the patent claims were drafted in apparatus form.

The Court of Customs and Patent Appeals turned its attention to process claims encompassing computer programs in In re Musgrave, 57 C. C. P. A. (Pat.) 1352, 431 F. 2d 882 (1970). In that case, the court emphasized the fact that Prater had done away with the mental-steps doctrine; in particular, the court rejected the Patent Office's continued reliance upon the "point of novelty" approach to claim analysis. Id., at 1362, 431 F. 2d, at 889.^[15] The court also announced a new standard for evaluating process claims under § 101: any sequence of operational steps was a patentable process under § 101 as long as it was within the "technological arts." Id., at 1366-1367, 431 F. 2d, at 893. This standard effectively disposed of any vestiges of the mental-steps doctrine remaining *201 after Prater and Bernhart.^[16] The "technological arts" standard was refined in In re Benson, 58 C. C. P. A. (Pat.) 1134, 441 F. 2d 682 (1971), in which the court held that computers, regardless of the uses to which they are put, are within the technological arts for purposes of § 101. Id., at 1142, 441 F. 2d, at 688.

In re Benson, of course, was reversed by this Court in Gottschalk v. Benson, 409 U. S. 63 (1972).^[17] Justice Douglas' opinion for a unanimous Court made no reference to the lower court's rejection of the mental-steps doctrine or to the new technological-arts standard.^[18] Rather, the Court clearly held that new mathematical procedures that can be conducted in old computers, like mental processes and abstract intellectual concepts, see id., at 67, are not patentable processes within the meaning of § 101.

*202 The Court of Customs and Patent Appeals had its first opportunity to interpret Benson in In re Christensen, 478 F. 2d 1392 (1973). In Christensen, the claimed invention was a method in which the only novel element was a mathematical formula. The court resurrected the point-of-novelty approach abandoned in Musgrave and held that a process claim in which the point of novelty was a mathematical equation to be solved as the final step of the process did not define patentable subject matter after Benson. 478 F. 2d, at 1394. Accordingly, the court affirmed the Patent Office Board of Appeals' rejection of the claims under § 101.

The Court of Customs and Patent Appeals in subsequent cases began to narrow its interpretation of Benson. In In re Johnston, 502 F. 2d 765 (1974), the court held that a record-keeping machine system which comprised a programmed digital computer was patentable subject matter under § 101. Id., at 771. The majority dismissed Benson with the observation that Benson involved only process, not apparatus, claims. 502 F. 2d, at 771. Judge Rich dissented, arguing that to limit Benson only to process claims would make patentability turn upon the form in which a program invention was claimed. 502 F. 2d, at 773-774.^[19] The court again construed Benson as limited only to process claims in In re Noll, 545 F. 2d 141 (1976), cert. denied, 434 U. S. 875 (1977); apparatus claims were governed by the court's pre-Benson conclusion that a programmed computer was structurally different from the same computer without that particular program. 545 F. 2d, at 148. In dissent, Judge Lane, joined by Judge Rich, argued that Benson should be read as a general proscription of the patenting of computer programs regardless of the form of the claims. 545 F. 2d, at 151-152. Judge Lane's interpretation of Benson was rejected by the majority *203 in In re Chatfield, 545 F. 2d 152 (1976), cert. denied, 434 U. S. 875 (1977), decided on the same day as Noll. In that case, the court construed Benson to preclude the patenting of program inventions claimed as processes only where the claims would pre-empt all uses of an algorithm or mathematical formula. 545 F. 2d, at 156, 158-159.^[20] The dissenting judges argued, as they had in Noll, that Benson held that programs for general-purpose digital computers are not patentable subject matter. 545 F. 2d, at 161.

Following Noll and Chatfield, the Court of Customs and Patent Appeals consistently interpreted Benson to preclude the patenting of a program-related process invention only when the claims, if allowed, would wholly pre-empt the algorithm itself. One of the cases adopting this view was In re Flook, 559 F. 2d 21 (1977),^[21] which was reversed in Parker v. Flook, 437 U. S. 584 (1978). Before this Court decided Flook, however, the lower court developed a two-step procedure for analyzing program-related inventions in light of Benson. In In re Freeman, 573 F. 2d 1237 (1978), the court held that such inventions must first be examined to determine whether a mathematical algorithm is directly or indirectly claimed; if an algorithm is recited, the court must then determine whether the claim would wholly pre-empt that algorithm. Only if a claim satisfied both inquiries was Benson considered applicable. 573 F. 2d, at 1245. See also In re Toma,