UCLA School of Law

The doctrine of equivalents is under attack - by the Federal Circuit, which has in recent years significantly constrained its application through the introduction of more aggressive estoppel and public disclosure rules; and by patent law scholars, who with increasing regularity urge that the doctrine be pared down or even fully repealed. This short Essay is framed as a response to one particular scholarly commentary, but it is in fact an attempt to state more broadly the case in favor of the doctrine of equivalents. My argument is that the doctrine serves three significant goals: it ensures that patent protection remains viable despite the limitations of language and foresight; it discourages wasteful efforts to perfect claim language; and, most importantly, it empowers the patent system to make better decisions by bringing into the process information that is systematically unavailable at the time when literal patent claims are written. No other patent system mechanism accomplishes these three objectives as completely. Thus, while I survey alternative approaches to claim articulation (what I describe in the title as substitutes for the doctrine of equivalents), my argument at its core is that the doctrine of equivalents has no substitutes. Not the reissue proceeding. Not the use of continuation applications. And certainly not more aggressive attempts at literal claim drafting.