Professor Eric Claeys is among the most thoughtful modern proponents of natural property rights. His new book, provided to conference participants in draft form, is typical of his rigorously analytical approach. It is an impressive articulation of a natural rights-based account of property. It significantly advances the debate over natural rights and should be taken seriously even by those who do not find it entirely convincing.

There are real-world political stakes in abstract-seeming questions of property theory because natural rights are often deployed to limit government regulation of property. Natural rights contrast with positivist accounts that locate the content of property rights in the substance of positive law. Where property rights come from the State, the State has broad authority to reconfigure those rights. Natural rights theorists, like Claeys, want property to be a bulwark against regulation and so insist that property has a pre-political core.

That core is deeply contested, however. For rights to be "natural," they must apply widely, if not universally, accepted, or at least be derivable in the abstract. To operate at this level, they generally underdetermine the substantive content of property law. Reasoning from natural rights, therefore, often devolves into contingent consequentialist or utilitarian arguments that look anything but natural.

Often, natural law is deployed to rationalize existing legal doctrines and rights. But this can sometimes feel like a bit of a failure of imagination, assuming aspects of law are necessary or inherent when in fact, they may be quite contingent. If natural law reasoning can defend even dramatically different substantive property rights, it becomes worryingly thin as a justificatory enterprise. It risks sliding into outcome-driven and conclusory analyses.