The Trespass Fallacy in Patent Law


The patent system is broken; so says the popular press, tech commentators, legal academics, lawyers, judges, and just about everyone else. One common refrain is that patents fail as property rights because patent infringement doctrine is not as clear, determinate and efficient as trespass doctrine is for real estate. This essay explains that this is a fallacious argument, suffering both logical and empirical failings. Logically, the comparison of patent boundaries to trespass commits what philosophers would call a "category mistake." It conflates the boundaries of an entire legal right (a patent), not with the boundaries of its conceptual counterpart (real estate), but rather with a single doctrine (trespass) that secures real estate only in a single dimension (geographic boundaries). Estate boundaries are defined along the dimensions of time, use and space, as reflected in numerous legal doctrines that secure estates, such as adverse possession, easements, nuisance, restrictive covenants, and future interests, among others. The proper conceptual analog for patent boundaries is "estate boundaries," not fences. Empirically, there are no formal studies of how trespass or even estate boundaries function in litigation; thus, complaints about the patent system’s indeterminacy are based solely on an idealized theory of how trespass should function; it’s the nirvana fallacy. Furthermore, anecdotal evidence and related studies suggest that estate boundaries are neither as clear nor as determinate as patent scholars assume it to be. In short, the trespass fallacy is driving an indeterminacy critique in patent law that is both empirically unverified and conceptually misleading. Until the indeterminacy critique is properly modeled and grounded in facts, legislators and courts might want to pause before continuing to make fundamental structural changes to the American patent system.