You ought to φ only if you may believe that you ought to φ

Abstract: In this paper I present an argument for the claim that we ought to do something only if we may believe that we ought to do it. More exactly, I defend the following principle about normative reasons: An agent A has decisive reason to φ only if she has sufficient reason to believe that she has decisive reason to φ. I argue that this principle follows from the plausible assumption that it must be possible for an agent to respond correctly to her reasons. In conclusion, I discuss some implications of this argument (given that some other standard assumptions about reasons hold). One such implication is that we are always in a position to be justified in believing all truths about what we have decisive reason (or ought) to do. In this paper I present an argument for an interesting claim about normative reasons: The Principle of Decisive Reasons (PDR): Necessarily, if A has decisive reason to φ, then A has sufficient reason to believe that she herself has decisive reason to φ. This claim is interesting because it has substantial consequences for some theories about reasons and for some issues that have recently been the focus of the philosophical debate on normativity. To anticipate one of these consequences, consider the widel