Under the Patent Act of 1952, not all inventions are patentable. The patentable subject matter requirement addresses the issue of which types of inventions will be considered for patent protection. Section 101 of the Patent Act broadly defines patentable subject matter as "any" new and useful "process, machine, manufacture, or composition of matter," or "improvement thereof."
However, despite this plain language, the Supreme Court has recognized three categories of subject matter outside the eligibility bounds of § 101—laws of nature, physical phenomena (the presently preferred terminology is “natural phenomena”), and abstract ideas.
The USPTO's current eligibility guidance is found in the Manual of Patent Examination Procedure (MPEP) Sections 2103 through 2106.07(c).
Current confusion about Section 101 doctrine dates back to the U.S. Supreme Court’s 1972 decision in Gottschalk v. Benson, which was further refined by the Supreme Court’s 1978 decision in Parker v. Flook. During the Benson–Flook epoch, patents on software and business method inventions were nearly unattainable.
In 1981, in Diamond v. Diehr, the Supreme Court opened the door to the patentability of computer programs by ruling that controlling a physical process, by executing a computer program, did not preclude patentability of the invention as a whole. After Diehr, patent practitioners found that software could be patented so long as it was combined with another patentable process or machine, even if the software was the only novel feature.
The Supreme Court’s decision in Mayo Collaborative Serv. v. Prometheus Labs., Inc. in 2012 effectively overruled Diamond v. Diehr, upending three decades of stable and predictable law described in Diehr. In 2014, in Alice Corp. Pty. Ltd. v. CLS Bank Int’l, citing Mayo, the Supreme Court compounded the chaos surrounding patent eligibility law. In the post-Alice epoch, the jurisprudence regarding patent eligibility under Section 101 appears to have "fallen off the rails."
Since the early twentieth century, at least ten Supreme Court cases have directly addressed the issue of patent-eligible subject matter.
Cases (since the Supreme Court's Alice decision in 2014) where the Federal Circuit held that the claims were patent eligble—the court either determined that the claims where not directed to an abstract idea, or found an "inventive concept"—are listed below.