The high profile cases Bilski v. Kappos and Association for Molecular Pathology v. United States Patent and Trademark Office have renewed public debate about the proper scope of patentable subject matter. The subject matter inquiry has traditionally been treated as a threshold inquiry in patent law, serving a gate-keeping function by defining the types of inventions that are eligible for patent protection. The Patent Office and courts have approached the subject matter inquiry both by determining whether an invention falls into a statutory category-processes, machines, manufactures, or compositions of matter-as well as by determining whether an invention falls into a category excluded from subject matter eligibility-often described in recent decades as laws of nature, natural phenomena, and abstract ideas.
In this Essay, we suggest that by focusing solely on shaping judicial interpretation of the exclusions from patentable subject matter, proponents of an expanded public domain fail to consider the possibility that states will expand what we term "interstitial exclusivities"-state-based legal rules, such as trade secret law and unfair competition law, that grant certain market exclusivities in inventions and that are not subject to federal constitutional limits on their duration. We argue that the expansion of existing interstitial exclusivities and the creation of new ones would alter existing incentive structures of intellectual property law, potentially provoking serious negative unintended consequences such as increased uncertainty surrounding patent validity, increased business costs, and increased secrecy in scientific research. We suggest instead that the creation of a public domain envisioned by ACLU and PUBPAT may be best achieved through concurrent efforts to enact legislative change, which would explicitly dedicate such inventions to a public domain.