What is Normativity?

The thesis that the concept of a reason is the fundamental normative concept is in the air. In this paper, I examine what it amounts to, how to formulate it, and how ambitious it should be. I distinguish a semantic version, according to which any normative predicate is definitionally reducible to a reason predicate, and a conceptual version, according to which the sole normative ingredient in any normative concept is the concept of a reason. Although I reject the semantic version, I examine its potential in some detail. And I claim that the conceptual version is plausible.