In Gottschalk v. Benson, 409 U.S. 63 (1972), the Supreme Court ruled that a mathematical algorithm for converting binary-coded decimal numbers into pure binary numbers could not be patented, because the claims were so broad that they would have monopolized the underlying math itself.1Cornell Law School. Gottschalk v. Benson The decision became the Court’s first major statement on the limits of computer-related patents and remains a foundation of the abstract-idea doctrine.
What Benson and Tabbot Tried to Patent
Gary Benson and Arthur Tabbot applied for a patent on a method of programming a general-purpose digital computer to convert binary-coded decimal numerals into pure binary numerals. Their application described a specific sequence of signals and mathematical steps to carry out the conversion, a routine internal operation for handling numerical data.2Cornell Law School. Gottschalk v. Benson – Paragraph: 1
The claims were not tied to any particular machine, hardware configuration, or end use. They covered the conversion method as performed on any general-purpose digital computer, which meant the applicants were effectively seeking rights over the mathematical logic itself.2Cornell Law School. Gottschalk v. Benson – Paragraph: 1
What the Supreme Court Held
The Court reversed the Court of Customs and Patent Appeals, which had sided with the inventors, and denied the patent. It concluded that the conversion procedure was an abstract mathematical concept, not a patentable process.1Cornell Law School. Gottschalk v. Benson
One factor the Court highlighted was that the steps could be carried out as mental arithmetic, without any computer at all. An algorithm that a person could work through in their head, the Court reasoned, does not become a patentable invention simply because a machine can run it faster.3Cornell Law School. Gottschalk v. Benson – Paragraph: 9
How the Ruling Fits Under 35 U.S.C. § 101
Federal patent law limits eligibility to four categories of new and useful inventions:4Office of the Law Revision Counsel. 35 U.S.C. § 101
- Processes
- Machines
- Manufactures
- Compositions of matter
The only category that plausibly fit Benson’s application was “process.” A process, in patent terms, is a series of acts performed on something to change it into a different state or thing.5Cornell Law School. Cochrane v. Deener – Paragraph: 21 Mathematical expressions of scientific truths, however, are treated as discoveries of basic principles rather than inventions. The Court found the conversion algorithm so abstract and sweeping that granting the claim would amount to patenting the formula itself.6Cornell Law School. Gottschalk v. Benson – Paragraph: 10
The Preemption Problem
The core rationale was preemption. The Court reasoned that the algorithm had no substantial practical use outside a digital computer, so a patent on it would reach every possible use of the formula. That kind of monopoly over a basic mathematical truth is what patent law is designed to prevent.7Cornell Law School. Gottschalk v. Benson – Paragraph: 22
By rejecting claims that broad, the Court kept the underlying tools of science and math in the public domain. A claim cannot capture the logic of a process in a way that shuts off every application of the math behind it.1Cornell Law School. Gottschalk v. Benson
What the Decision Left Open
The ruling did not close the door on software or math-based inventions. Patent law draws a line between a basic law of nature or abstract idea, which cannot be patented, and a specific practical application of that concept, which may still qualify.8USPTO. MPEP § 2106 – Section: I. TWO CRITERIA FOR SUBJECT MATTER ELIGIBILITY Utility alone is not enough; the claimed invention has to fit one of the four statutory categories and cannot be directed to an abstract idea on its own. Benson’s application failed that test because it claimed the math rather than a particular technological use of it.