Abstract

Benjamin Kiesewetter has recently provided an argument to the effect that necessarily, if one has decisive reason to φ, then one has sufficient reason to believe that she herself has decisive reason to φ. If sound, this argument has important implications for several debates in contemporary normative philosophy. I argue that the main premise in the argument is problematic and should be rejected. According to this premise (PRR), necessarily, one can respond correctly to all the decisive reasons one has. I show that PRR is confronted with counterexamples and presupposes an implausible commensurability of all kinds of reasons. If so, the conclusion in Kiesewetter’s argument doesn’t follow. I also discuss further implications of my objections to PRR for a specific family of ‘ought’ implies ‘can’ principles and ability constraints on reasons, and the consequences that these could have for a number of contemporary debates in normative philosophy.