A Hyperintensional Approach To Normativity: Deontic Modals, Reasons, Properties.

I argue that normativity is hyperintensional. I provide two arguments: one deductive, one abductive. First, I simply prove that the contrary thesis leads to falsity; second, I claim that a hyperintensional theory of normativity fares better than its rivals in terms of elegance, theoretical simplicity, and explanatory power. After introducing and defending the notion of hyperintensional equivalence, I discuss a hyperintensional deontic logic, which I prove sound and complete with respect to a version of truthmaker semantics. I suggest how to extend this logic to the first-order and how to make it compatible with a scalar semantics. I then formulate a logic of normative reasons based on justification logics. I prove that normative reasons cannot be numerically measured (in a precise sense), and that the scale of normative reasons, if any, is therefore not ratio, interval, or ordinal (in a precise measurement-theoretic sense), and I discuss the consequences of this result for normative theory. In the end I argue that a higher-order supervenience principle, together with a hyperintensional account of properties, deflect Jackson-style arguments against nonreductive normative nonnaturalism.