A Unique Type (of) Problem for Theories of Law

David Armstrong claims that a law of nature is both a universal as well as a state of affairs. Unfortunately, this leaves his account vulnerable to a “logician’s protest”, first privately raised by Tichý, that appeals to the type theory of higher-order logic. In this paper, I flesh out the objection and show how Armstrong’s cursory response is inadequate. I argue that the logician’s protest is a very serious problem for Armstrong, as well as any other account of lawhood that posits such a ‘dual nature’ (according to which a law is both a universal and state of affairs). As a result, the logician’s protest serves as an important dilemma for any theory of laws: laws of nature can be identified with universals or with states of affairs, but not both. I conclude that the seriousness of the logician’s protest is an underappreciated constraint on the metaphysics of one's theory.