Bilski and the Ambiguity of 'An Unpatentable Abstract Idea'

In Bilski v. Kappos, the Supreme Court affirmed the PTO’s rejection of a number of patent claims under the patent-eligibility provision of section 101 of the Patent Act. Bilski positions the abstract-ideas doctrine as the primary gatekeeper of patent eligibility for many types of claims, but it teaches the patent community almost nothing about what constitutes an unpatentable abstract idea. This Article outlines one strategy for doing what the Supreme Court chose not to do, namely giving meaningful content to the exclusion of abstract ideas from patent eligibility. Conventionally, the principal problem with the abstract-ideas doctrine of section 101 is understood to be vagueness: abstraction is a continuous variable, and the dividing line that differentiates unpatentable abstractions from patentable applications is known to be difficult to identify with precision. While vagueness is a real issue, this Article argues that there is a more fundamental problem that must be addressed prior to vagueness. The phrase “an unpatentable abstract idea” is multiply ambiguous, as the phrase invokes entirely different concepts in different situations. Examining Supreme Court and Federal Circuit precedent prior to Bilski, this Article argues that “an unpatentable abstract idea” means four different things in four different contexts, and it thereby identifies four distinct types of unpatentable abstract ideas that may merit different treatment under the doctrine of patent eligibility for different policy reasons