Guest post by Jeffrey A. Lefstin, Professor of Law, University of California, Hastings College of Law
As the Supreme Court prepares to take up Alice Corp. v. CLS Bank, a major question the Court may confront is to what extent an “inventive concept” is necessary for patent eligibility under § 101. In Mayo v. Prometheus, the Court suggested that “conventional and obvious” activity cannot transform a law of nature or abstract idea into a patent-eligible invention. The Court seemingly revived Parker v. Flook, which held that only “inventive applications” of abstract ideas are patent-eligible. But when the Federal Circuit heard CLS Bank, divided as the court was, both Judge Rader and Judge Lourie emphatically rejected the idea that Mayo demands “inventiveness” for patent-eligibility.
In both Flook and Mayo, the Supreme Court anchored the requirement for inventive application in Neilson v. Harford, the famous English case on James Neilson’s hot-blast smelting process. The Court in Flook and Mayo focused on this passage appearing in Baron Parke’s opinion for the Court of Exchequer:
We think the case must be considered as if the principle being well known, the plaintiff had first invented a mode of applying it by a mechanical apparatus to furnaces; and his invention then consists in this—by interposing a receptacle for heated air between the blowing apparatus and the furnace.
Flook took this language to mean that an underlying idea or discovery should be treated as part of the prior art; Mayo took it to mean that a claim is patent-eligible only if the application of a discovery or idea is inventive or unconventional.
However, a reading of the Exchequer’s full opinion tells the opposite story. Neilson’s patent was sustained because his application was entirely conventional and obvious. The defendant’s challenge in Neilson was primarily a scope of enablement argument: Neilson had disclosed that the blast should be heated before introducing it into the furnace, but disclosed next to nothing about the heating means. In refuting the defendant’s challenge, both the patentee and the judges of the Exchequer emphasized that the mode and apparatus for heating air were old and well known in the field, and represented no invention by Neilson.
So why did Baron Parke write that Neilson’s discovery – his ‘principle’ – should be regarded as “well known”? The court was wrestling with the question of whether Neilson had claimed a patentable manufacture, or the abstract principle that hot air was superior to cold. And if a manufacture, was Neilson entitled to reach the accused blast furnace, which employed a different heating apparatus? The Exchequer had faced the same questions seven years earlier in Minter v. Wells, involving a patent to an adjustable chair. The defendant in Minter had argued that the patentee was trying to claim a well-known principle of mechanics: the self-adjusting lever. Alternatively, if the claim was to the chair rather than the principle, the patent should be restricted to the inventor’s particular embodiment. Baron Parke concluded instead that the patentee had claimed the application of the self-adjusting leverage to an adjustable chair. Therefore, the patent was not drawn to an abstract principle, and might extend to other chairs embodying the same application but with a different arrangement.
Minter thereby established that a patent might claim the application of a well-known principle to new ends, and might extend beyond the exact machinery employed by the patentee. In the famous passage from Neilson, Parke was applying the same doctrine to Neilson’s patent – except that Neilson’s ‘principle’ was new rather than well-known. Neilson was a more difficult case because, given Neilson’s minimal disclosure, the scope of enablement was more dubious than in Minter. But a special jury verdict on that point ultimately carried the day for Neilson.
Neilson was only one of some twenty cases asserted by Neilson in England and Scotland. Other decisions following and interpreting Neilson leave no doubt that the case stood not for inventive application, but for the distinction between principles in the abstract and patentable applications. For example, in a case litigated the next year, Househill v. Neilson, the Court of Sessions stated:
The main merit, the most important part of the invention, may consist in the conception of the original idea—in the discovery of the principle in science, or of the law of nature, stated in the patent, and little or no pains may have been taken in working out the best manner and mode of the application of the principle to the purpose set forth in the patent.
Neilson was understood the same way in the Supreme Court’s landmark 19th-century opinions that discussed Neilson extensively, such as Le Roy, Morse, and Tilghman. Further, in late 19th-century and early 20th-century American cases and treatises, it was black-letter law that while abstract principles and discoveries could not be patented, a practical application was patent-eligible without the need for inventive application – subject to certain exclusions such as the ‘mental steps’ rule.
As I wrote about last year, the actual origin of the inventive application test was Justice Douglas’s opinion in Funk Brothers, in 1948. The dubious history of the inventive application test in the wake of Funk suggests we would have been better served by following Justice Frankfurter instead of Justice Douglas. For it was Frankfurter’s concurrence that embraced the spirit of Neilson and the historical tradition: the claims to bacterial compositions in Funk were unpatentable not because they added or changed little relative to a law of nature or natural phenomenon, but because the patentee was claiming the idea of compatible strains instead of his practical application.
I write about the hot-blast cases, and the history of the inventive application test, in an article available here.