<em>Alapatt</em> Redux: Support for Functional Language in Software Patent Claims

The Federal Circuit has suggested in some recent cases that any algorithm can serve as adequate structural support for a means-plus-function element in a software patent claim under § 112(f). A recent proposal by Mark Lemley fully endorses this proposition and seeks its broader application. The concept of an algorithm, however, is too slippery to serve as the basis for such a rule. In this Article, I argue that this overreliance on the algorithm concept originated in a revisionist gloss on the Federal Circuit's 1994 Alappat decision.

Informed by a closer reading of what Alappat actually has to say about claim construction under § 112(f), I propose a more stable "concrete causation" standard that is not only applicable to all technologies, but also well-aligned with the reforms in the software field intended by Lemley's proposal.