CITE:  437 U.S. 584
CMON:  June 1978
PLAIN: Flook
DEFND: Parker, Acting Commissioner of Patent and Trademark Office
COURT: Supreme Court of the United States
DATE:  June 22, 1978


On writ of certiorari, 196 USPQ 864, to Court of Customs and Patent Appeals;
195 USPQ 9.

Application for patent of Dale R. Flook, Serial No. 194,032, filed Oct. 29,
1971. On writ of certiorari to review judgment reversing rejection of claims
1-10. Reversed; Mr. Justice Stewart, with whom The Chief Justice, and
Mr. Justice Rehnquist join, dissenting, with opinion.

  Some novel and useful computer programs are not patentable.  Process is
  not unpatentable because it contains law of nature or mathematical
  algorithm.  Unknown algorithms can be prior art.  Process has to be
  new and useful, independent of any mathematical algorithms used.



Respondent applied for a patent on a "Method For Updating Alarm Limits".
The only novel feature of the method is mathematical formula. In Gottschalk
v. Benson, 409 U.S. 63, 175 USPQ 673, we held that the discovery of a novel
and useful mathematical formula may not be patented. The question in this
case is whether the identification of a limited category of useful, though
conventional, post-solution applications of such a formula makes
respondent's method eligible for patent protection.


An "alarm limit" is a number. During catalytic conversion processes,
operating conditions such as temperature, pressure, and flow rates are
constantly monitored. When any of these "process variables" exceeds a
predetermined "alarm limit", an alarm may signal the presence of an
abnormal condition indicating either inefficiency or perhaps danger.
Fixed alarm limits may be appropriate for a steady operation, but during
transient operating situations, such as start-up, it may be necessary to
"update" the alarm limits periodically.

Respondent's patent application describes a method of updating alarm
limits. In essence, the method consists of three steps: an initial step
which merely measures the present value of the process variable (e.g., the
temperature); an intermediate step which uses an algorithm{1} to calculate
an updated alarm limit value; and a final step in which the actual alarm
limit is adjusted to the updated value.{2} The only difference between the
conventional methods of changing alarm limits and that described in 
respondent's application rests in the second step - the mathematical
algorithm or formula. Using the formula, an operator can calculate an
updated alarm limit once he knows and original alarm base, the appropriate 
margin of safety, the time interval that should elapse between each
updating, the current temperature (or other process variable), and the
appropriate weighting factor to be used to average the original alarm base 
and the current temperature.

The patent application does not purport to explain how to select the
appropriate margin of safety, the weighting factor, or any of the other
variables. Nor does it purport to contain any disclosure relating to the
chemical processes at work, the monitoring of process variable, 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. Although the
computations can be made by pencil and paper calculations, the abstract
of disclosure makes it clear that the formula is primarily useful for
computerized calculations producing automatic adjustments in alarm

The patent claims cover any use of respondent's formula for updating the
value of an alarm limit on any process variable involved in a process
comprising the catalytic chemical conversion of hydrocarbons. Since there
are numerous processes of that kind in the petrochemical and oil refining 
industries,{4} the claims cover a broad range of potential uses of the
method. They do not, however, cover every conceivable application of the


The patent examiner rejected the application. He found that the mathematical
formula constituted the only difference between respondent's claims and the
prior art and therefore a patent on this method "would in practical effect
be a patent on the formula or mathematics itself."{5} The examiner concluded 
that the claims did not describe a discovery that was eligible for patent

The Board of Appeals of the Patent and Trademark Office sustained the
examiner's rejection. The Board also concluded that the "point of novelty
in [respondent's] claimed method" {6} lay in the formula or algorithm
described in the claims, a subject matter that was unpatentable under
Benson, supra.

The Court of Customs and Patent Appeals reversed. 559 F.2d 21. It read
Benson as applying only to claims that entirely pre-empt a mathematical
formula or algorithm, and noted that respondent was only claiming on the
use of his method to update alarm limits in a process comprising the
catalytic chemical conversion of hydrocarbons. The court reasoned that
since the mere solution of the algorithm would not constitute infringement
of the claims, a patent on the method would not pre-empt the formula.

The acting Commissioner of Patents and Trademarks filed a petition for a
writ of certiorari, urging that the decision of the Court of Customs and
Patent Appeals will have a debilitating effect on the rapidly expanding
computer "software" industry, {7} and will require him to process thousands
of additional patent applications. Because of the importance of the
question, we granted certiorari, U.S., 196 USPQ 864.


This case turns entirely on the proper construction of Section 101 of
the Patent Code, which describes the subject matter that is eligible for
patent protection. {8} It does not involve the familiar issues of novelty 
and obviousness that routinely arise under Sections 102 and 103 when the
validity of a patent is challenged. For the purpose of our analysis, we
assume that respondent's formula is novel and useful and that he discovered 
it. We also assume, since respondent does not challenge the examiner's
finding, that the formula is the only novel feature of respondent's method.
The question is whether the discovery of this feature makes an otherwise
conventional method eligible for patent protection.

The plain language of Section 101 does not answer the question. It is
true, as respondent argues, that his method is a "process" in the ordinary
sense of the word. {9} But that was also true of the algorithm, which
described a method for converting binary-coded decimal numerals into
pure binary numbers, that was involved in Gottschalk v. Benson. The holding
that the discovery of that method could not be patented as a "process"
forecloses a purely literal reading of Section 101.{10}  Reasoning that an
algorithm, or mathematical formula, is like a law of nature, Benson applied
the established rule that a law of nature cannot be the subject of a patent.
Quoting from earlier cases, we said:

    "'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.
    Phenomena of nature, though just discovered, mental processes, and
    abstract intellectual concepts are not patentable, as they are the
    basic tools of scientific and technological work." 409 U.S., at 67.

The line between a patentable "process" and an unpatentable "principle"
does not always shimmer with clarity. Both are "conception[s] of the mind,
seen only by [their] effects when being executed or performed." Tilghman v.
Proctor, 102 U.S. 707, 728. In Benson we concluded that the process
application in fact sought to patent an idea, noting that:

    "The mathematical formula involved here has not substantial practical
    application except in connection with a digital computer, which means
    that if the judgment below is affirmed, the patent would wholly pre-
    empt the mathematical formula and in practical effect would be a
    patent on the algorithm itself." 409 U.S., at 71-72.

Respondent correctly points out that this language does not apply to his
claims. He does not seek to "wholly pre-empt the mathematical formula",
since there are uses of his formula outside the petrochemical and oil
refining industries that remain in the public domain. And he argues that
the presence of specific "post-solution" activity - the adjustment of the
alarm limit to the figure computed according to the formula - distinguishes
this case from Benson and makes his process patentable. We cannot agree.

The notion that post-solution activity, no matter how conventional or
obvious in itself, can transform an unpatentable principle into a patentable
process exalts form over substance. A competent draftsman could attach some
form of post-solution activity to almost any mathematical formula; the 
Pythagorean Theorem would not have been patentable, or partially patentable,
because a patent application contained a final step indicating that the
formula, when solved, could be usefully applied to existing surveying
techniques.{11}  The concept of patentable subject matter under Section 101
is not "like a nose of wax which may be turned and twisted in any direction
* * *." White v. Dunbar, 119 U.S. 47, 51.

Yet it is equally clear that a process is not unpatentable simply because
is contains a law of nature or a mathematical algorithm. See Eibel Process
Co. v. Minnesota and Ontario Paper Co., 261 U.S. 45; Tilghman v. Proctor,
102 U.S., 707. {12}  For instance, in Mackay Radio and Telegraph Co. v.
Radio Corporation of America, 306 U.S. 86, the applicant sought a
patent on a directional antenna system in which the wire arrangement was
determined by the logical application of a mathematical formula. Putting the
question of patentability to one side as a preface to his analysis of the
infringement issue, Mr. Justice Stone, writing for the Court, explained:

    "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." 306 U.S. at 94.

Funk Bros. Seed Co. v. Kalo Co., 333 U.S. 127, 130, expresses a similar

    "He who discovers a hitherto unknown phenomenon of nature has no claim
    to a monopoly of it which the law recognizes. If there is to be
    invention from such a discovery, it must come from the application of
    the law of nature to a new and useful end."

Mackay Radio and Funk Bros. point to the proper analysis for this case:
The process itself, not merely the mathematical algorithm, must be new
and useful. Indeed, the novelty of the mathematical algorithm is not a
determining factor at all. Whether the algorithm was in fact known or
unknown at the time of the claimed invention, as one of the "basic tools
of scientific and technological work", see Gottschalk v. Benson, supra,
409 U.S., at 67, it is treated as though it were a familiar part of the
prior art.

This is also the teaching of our landmark decision in O'Reilly v. Morse,
15 How. 62. In that case the Court rejected Samuel Morse's broad claim
covering any use of electromagnetism for printing intelligible signs,
characters or letters at a distance. Id., at 112-121. In reviewing earlier
cases applying the rule that a scientific principle cannot be patented,
the Court placed particular emphasis on the English case of Neilson et al.
v. Harford, Webster's Patent Cases 273 (1844), which involved the
circulation of heated air in a furnace system to increase its efficiency.
The English Court rejected the argument that the patent merely covered
the principle that furnace temperature could be increased by injecting
hot air, instead of cold into the furnace. That court's explanation of
its decision was relied on by this court in Morse:

    "'It is very difficult to distinguish it [the Neilson patent] from
    the specification of a patent for a principle, and this at first
    created in the minds of the court much difficulty; but after full
    consideration we think that the plaintiff does not merely claim a
    principle, but a machine, embodying a principle, and a very valuable 
    one. We think the case must be considered as if the principle being
    well known, the plaintiff had first invented a mode of applying it
    * * *." 15 How., at 115 (emphasis added). {13}

We think this case must also be considered as if the principle or
mathematical formula were well known.

Respondent argues that this approach improperly imports into Section 101
the considerations of "inventiveness" which are the proper concerns of
Section 102 and 103. {14} This argument is based on two fundamental

First, respondent incorrectly assumes that if a process application 
implements a principle in some specific fashion, it automatically falls
within the patentable subject matter of Section 101 and the substantive 
patentability of the particular process can then be determined by the
conditions of Section 102 and Section 103. This assumption is based on
respondent's narrow reading of Benson, supra, and is as untenable in the
context of Section 101 as it is in the context of that case. It would make
the determination of patentable subject matter depend simply on the
draftsman's art and would ill serve the principles underlying the
prohibition against patents for "ideas" or phenomena of nature. The rule
that the discovery of a law of nature cannot be patented rests, not on
the notion that natural phenomena are not processes, but rather on the
more fundamental understanding that they are not the kind of "discoveries"
that the statute was enacted to protect. {15} The obligation to determine
what type of discovery is sought to be patented must precede the 
determination of whether that discovery is, in fact, new or obvious.

Second, respondent assumes that the fatal objection to his application
is the fact that one of its components - the mathematical formula -
consists of unpatentable subject matter. In countering this supposed 
objection, respondent relies on opinions by the court of Customs and
Patent Appeals which reject the notion "that a claim may be dissected,
the claim components searched in the prior art, and, if the only component
found novel is outside the statutory classes of invention, the claim
may be rejected under 35 U.S.C. Section 101." Application of Chatfield,
545 F.2d 152, 158 (CCPA 1976). {16} Our approach to respondent's
application is, however, not at all inconsistent with the view that a
patent claim must be considered as a whole. Respondent's process is 
unpatentable under Section 101 not because it contains a mathematical
algorithm as one component, but because once that algorithm is assumed 
to be within the prior art, the application, considered as a whole,
contains no patentable invention. Even though a phenomenon of nature or
mathematical formula may be well known, an inventive application of the 
principle may be patented. Conversely, the discovery of such a phenomenon
cannot support a patent unless there is some other inventive concept in
its application.

Here it is absolutely clear that respondent's application contains
no claim of patentable invention. The chemical processes involved in
catalytic conversion of hydrocarbons are well known; as are the practice
of monitoring the chemical process variable, the use of alarm limits to
trigger alarms, the notion that alarm limit values must be recomputed and
readjusted, and the use of computers for "automatic process
monitoring-alarming." {17} Respondent's application simply provides a
new and presumably better method for calculating alarm limit values.
If we assume that that method was also known, as we must under the
reasoning in Morse, then respondent's claim is, in effect, comparable
to a claim that the formula 2r can be usefully applied in determining
the circumference of a wheel. {18}  As the Court of Customs and Patent 
Appeals has explained, "if a claim is directed essentially to a method
of calculating, using a mathematical formula, even if the solution is
for a specific purpose, the claimed method is nonstatutory". Application
of Richman, 563 F.2d 1026, 1030 (1977).

To a large extent our conclusion is based on reasoning derived from
opinions written before the modern business of developing programs for
computers was conceived. The youth of the industry may explain the
complete absence of precedent supporting patentability. Neither the
dearth of precedent, nor this decision, should therefore be interpreted
as reflecting a judgment that patent protection of certain novel and
useful computer programs will not promote the progress of science and 
the useful arts, or that such protection is undesirable as a matter of
policy. Difficult questions of policy concerning the kinds of programs
that may be appropriate for patent protection and the form and duration
of such protection can be answered by Congress on the basis of current
empirical data not equally available to this tribunal. {19}

It is our duty to construe the patent statues as they now read, in
light of our prior precedents, and we must proceed cautiously when we are
asked to extend patent rights into areas wholly unforeseen by Congress.
As Mr. Justice White explained in writing for the Court in Deepsouth
Packing Co. v. Laitram Corp., 406 U.S. 518, 531:

    "[W]e should not expand patent rights by overruling or modifying
    our prior cases construing the patent statutes, unless the argument
    for expansion of privilege is based on more than mere inference from 
    ambiguous statutory language. We would require a clear and certain
    signal from Congress before approving the position of a litigant who,
    as respondent here, argues that the beachhead of privilege is wider,
    and the area of public use narrower, than the courts had previously
    thought. No such signal legitimizes respondent's position in this

The judgment of the Court of Customs and Patent Appeals is Reversed.


Claim 1 of the patent describes the method as follows:

    "1. A method for updating the value of at least one alarm limit on
    at least one process variable involved in a process comprising the
    catalytic chemical conversion of hydrocarbons wherein said alarm 
    limit has a current value of 

                                     Bo + K

    "wherein Bo is the current alarm base and K is a predetermined
    alarm offset which comprises:

    "(1) Determining the present value of said process variable, said
     present value being defined as PVL;

    "(2) Determining a new alarm base, B1, using the following equation:

                               B1 = Bo (1.0-F) + PVL(F)

    "where F is a predetermined number greater than zero and less than 1.0;

    "(3) Determining an updated alarm limit which is defined as B1+K;
    and thereafter

    "(4) Adjusting said alarm limit to said updated alarm limit value."

    App., at 63.

In order to use respondent's method for computing a new limit, the operator
must make four decisions. Based on his knowledge of normal operating
conditions, he first selects the original "alarm base" (Bo); if a temperature
of 400 degrees is normal, that may be the alarm base. He next decides on an 
appropriate margin of safety, perhaps 50 degrees; that is his "alarm offset"
(K). The sum of the alarm base and the alarm offset equals the alarm limit.
Then he decides on the time interval that will elapse between each updating;
that interval has no effect on the computation although it may, of course,
be of great practical importance. Finally, he selects a weighting factor (F)
which may be any number between 99% and 1%,{20} and which is used in the
updating calculation.

If the operator has decided in advance to use an original alarm base (Bo)
of 400 degrees, a constant alarm offset (K) of 50 degrees, and a weighting
factor (F) of 80%, the only additional information he needs in order to
compute an updated alarm limit (UAV), is the present value of the process
variable (PVL). The computation of the updated alarm limit according to
respondent's method involves these three steps:

    First, at the predetermined interval, the process variable is measured;
    if we assume the temperature is then 425 degrees, PVL will then equal

    Second, the solution of respondent's novel formula will produce a new
    alarm base (B1) that will be a weighted average of the preceding alarm
    base (Bo) of 400 degrees and current temperature (PVL) of 425. It will
    be closer to one or the other depending on the value of the weighting 
    factor (F) selected by the operator. If F is 80%, that percentage of
    425 (340) plus 20% (1-F) of 400 (80) will produce a new alarm base of
    420 degrees.

    Third, the alarm offset (K) of 50 degrees is then added to the new
    alarm base (B1) of 420 to produce the updated alarm limit (UAV) of 470.

The process is repeated at the selected time intervals. In each updating
computation, the most recently calculated alarm base and the current
measurement of the process variable will be substituted for the
corresponding numbers in the original calculation, but the alarm offset
and the weighting factor will remain constant.


Mr. Justice Stewart, with whom The Chief Justice and Mr. Justice Rehnquist
join, dissenting.

It is a commonplace that laws of nature, physical phenomena, and abstract
ideas are not patentable subject matter. {1'} A patent could not issue, in
other words, on the law of gravity, or the multiplication tables, or the
phenomena of magnetism, or the fact that water at sea level boils at
100 degrees centigrade and freezes at zero - even though newly discovered.
Le Roy v. Tatham, 14 How. 156, 175; O'Reilly v. Morse, 15 How. 62, 112-121;
Rubber-Tip Pencil Co. v. Howard, 20 Wall. 498, 507; Tilghman v. Proctor, 
102 U.S. 707; Mackay Co. v. Radio Corp., 306 U.S. 86, 94; Funk Bros. Seed
Co. v. Kalo Co., 333 U.S. 127, 130.

The recent case of Gottschalk v. Benson, 409 U.S. 63, stands for no more
than this long-established principle, which the Court there stated in the
following words:

    "Phenomena of nature, though just discovered, mental processes, and
    abstract intellectual concepts are not patentable, as they are the
    basic tools of scientific and technological work." Id., at 67.

In Benson the Court held unpatentable claims for an algorithm that "were
not limited to any particular art or technology, to any particular apparatus
or machinery, or to any particular end use." Id., at 64.  A patent on such
claims, the Court said, "would wholly pre-empt the mathematical formula and
the practical effect would be a patent on the algorithm itself." Id. at 72.

The present case is a far different one. The issue here is whether a
claimed process {2'} loses its status of subject matter patentability
simply because one step in the process would not be patentable subject 
matter if considered in isolation. The Court of Customs and Patent Appeals
held that the process is patentable subject matter, Benson being 
inapplicable since "[t]he present claims do not preempt the formula or
algorithm contained therein, because solution of the algorithm, per se,
would not infringe the claims." 559 F.2d 21, at 23.

That decision seems to me wholly in conformity with basic principles of
patent law. Indeed, I suppose that thousands of process and combinations
have been patented that contained one or more steps or elements that
themselves would have been unpatentable subject matter. {3'}  Eibel Process
Co. v. Minnesota & Ontario Paper Co., 261 U.S. 45, is a case in point.
There the Court upheld the validity of any improvement patent that made
use of the law of gravity, which by itself was clearly unpatentable.
See also, e.g., Tilghman v. Proctor, 102 U.S. 707.

The Court today said it does not turn its back on these well-settled
precedents, ante, at , but it 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. Section 101 the criteria of novelty and inventiveness. Section
101 is concerned with only subject matter patentability. Whether a patent
will actually issue depends upon the criteria of Sections 102 and 103,
which include novelty and inventiveness, among many others. It may well
be that under the criteria of Sections 102 and 103 no patent should issue
on the process claimed in this case, because of anticipation, abandonment,
obviousness, or for some other reason. But in my view the claimed process
clearly meets the standards of subject matter patentability of Section 101.

In short, I agree with the Court of Customs and Patent Appeals in this
case, and with the carefully considered opinions of that court in other
cases presenting the same basic issue. See In re Freeman, 573 F.2d 1237;
In re Richman, 563 F.2d 1026 (CCPA); In re Castelet, 562 F.2d 1236 (CCPA);
In re Deutsch, 553 F.2d 689 (CCPA); In re Chatfield, 545 F.2d 152 (CCPA).
Accordingly, I would affirm the judgment before us.


{1} We use the word "algorithm" in this case, as we did in Gottschalk v.
Benson, 409 U.S. 63, 65, to mean "[a] procedure for solving a given type
of mathematical problem * * *"

{2} Claim 1 of the patent is set forth in the appendix to this opinion,
which also contains a more complex description of these three steps.

{3} App., at 13.

{4} Examples mentioned in the abstract of disclosure include naphtha
reforming, petroleum distillate and petroleum residuum cracking,
hydrocracking and desulfurization, aromatic hydrocarbon and paraffin 
isomerization and disproportionation, paraffin-olefin alkylation and
the like. Id., at 8.

{5} Id., at 47.

{6} Id., at 60.

{7} The term "software" is used in the industry to describe computer
programs. The value of computer programs in use in the United States
in 1976 was placed at $43.1 billion, and projected at $70.7 billion by 
1980 according to one industry estimate. See Brief Amicus Curiae for the
Computer and Business Equipment Manufacturers Association, at 17-18, n.16.

{8} 35 U.S.C. Section 101 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." Section 100(b) provides:

    "The term 'process' means process, art or method, and includes a new
    use of a known process, machine, manufacture, composition of matter,
    or material.

{9} The statutory definition of "process" is broad. See n. 8, supra. An
argument can be made, however, that this Court has only recognized a
process as within the statutory definition when it either was tied to a 
particular apparatus or operated to change materials to a "different state
or thing." See Cochrane v. Deener, 94 U.S. 780, 787-788. As in Benson, we
assume that a valid process patent may issue even if it does not meet one
of these qualifications of our earlier precedents. 409 U.S., at 71.

{10} In Benson we phrased the issue in this way:

"The question is whether the method described and claimed is a 'process'
within the meaning of the Patent Act." 409 U.S., at 64.

{11} It should be noted that in Benson there was a specific end use
contemplated for the algorithm-utilization of the algorithm in computer
programming. See Application of Chatfield, 545 F.2d 152, 161 (CCPA 1976)
(Rich, J., dissenting). Of course, as the Court pointed out, the formula
had not other practical application; but it is not entirely clear why a
process claim is any more or less patentable because the specific end use
contemplated is the only one for which the algorithm has any practical

{12} In Eibel Process Co. the Court upheld a patent on an improvement on
a papermaking machine that made use of the law of gravity to enhance the
flow of the product. The patentee, of course, did not claim to have
discovered the force of gravity, but that force was an element in his
novel conception.

Tilghman v. Proctor involved a process claim for "the manufacturing of
fat acids and glycerine from fatty bodies." The Court distinguished the
process from the principle involved as follows:

    "[T]he claim of the patent is not for a mere principle. The chemical
    principle or scientific fact upon which it is founded is, that the
    elements of neutral fat require to be severally united with an atomic
    equivalent of water in order to separate from each other and become
    free. This chemical fact was not discovered by Tilghman. He only claims
    to have invented a particular mode of bringing about the desired
    chemical union between the fatty elements and water." 102 U.S. at 729.

{13} See also Risdon Locomotive Works v. Medart, 158 U.S. 68;
Tilghman v. Proctor, supra.

{14} Sections 102 and 103 establish certain conditions, such as novelty
and nonobviousness, to patentability.

{15} The underlying notion is that a scientific principle, such as that
expressed in respondent's algorithm, reveals a relationship that has always

"As example of such a discovery [of a scientific principle] was Newton's
formulation of the law of universal gravitation, relating the force of
attraction between two bodies, F, to their masses, m and m', and the square
of the distance, d, between their centers, according to the equation
F=mm'/d. But this relationship always existed - even before Newton announced
his celebrated law. Such 'mere' recognition of a theretofore existing
phenomenon or relationship carries with it now rights to exclude others
from its enjoyment. * * * Patentable subject matter must be new (novel);
not merely heretofore unknown. There is a very compelling reason for this
rule. The reason is founded upon the propostion that in granting patent 
rights, the public must not be deprived of any rights that it theretofore
freely enjoyed." P Rosenberg, Patent Law Fundamentals, Section 4, at 13

{16} Section 103, by its own terms, requires that a determination of
obviousness be made by considering "the subject matter as a whole."
35 U.S.C. Section 103. Although this does not necessarily require that
analysis of what is patentable subject matter under Section 101 proceed
on the same basis, we agree that it should.

{17} App., at 22.

{18} Respondent argues that the inventiveness of his process must be
determined as of "the time the invention is made" under Section 103, and
that, therefore, it is improper to judge the obviousness of his process by 
assessing the application of the formula as though the formula were part
of the prior art. This argument confuses the issue of patentable subject
matter under Section 101 with that of obviousness under Section 103. Whether
or not respondent's formula can be characterized as "obvious", his process
patent rests solely on the claim that his mathematical algorithm, when
related to a computer program, will improve the existing process for 
updating alarm units. Very simply, our holding today is that a claim for
an improved method of calculation, even when tied to a specific end use,
is unpatentable subject matter under Section 101.

{19} Articles assessing the merits and demerits of patent protection for
computer programming are numerous. See, e.g., Davis, Computer Programs and
Subject Matter Patentability, 6 Rutgers Journal of Computers and the Law 1,
and articles cited therein, at 2 n. 5 (1976). Even among those who favor 
patentability of computer programs, there is questioning of whether the
17-year protection afforded by the current Patent Act is either needed or
appropriate. See id., at 20 n. 133.

{20} More precisely, it is defined as a number greater than 0, but less
than 1.

{1'} 35 U.S.C. Section 101 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.

{2'} 35 U.S.C. Section 100(b) provides:

"The term 'process' means process, art or method, and includes a new use
of a known process, machine, manufacture, composition of matter, or

{3'} In Gottschalk v. Benton, the Court equated process and product patents
for the purpose of its inquiry: "We dealt there with a 'product' claim,
while the present case deals with a 'process' claim. But we think 
the same principle applies." 409 U.S., at 67-68.