Bart Streumer

What is the relation between entailment and reasons for belief? In this paper, I discuss several answers to this question, and I argue that these answers all face problems. I then propose the following answer: for all propositions p1,...,pn and q, if the conjunction of p1,..., and pn entails q, then there is a reason against a person's both believing that p1,..., and that pn and believing the negation of q. I argue that this answer avoids the problems that the other answers to this question face, and that it does not face any other problems either. I end by showing what the relation between deductive logic, reasons for belief and reasoning is if this answer is correct.

Many philosophers claim that it cannot be the case that a person ought to perform an action if this person cannot perform this action. However, most of these philosophers do not give arguments for the truth of this claim. In this paper, I argue that it is plausible to interpret this claim in such a way that it is entailed by the claim that there cannot be a reason for a person to perform an action if it is impossible that this person will perform this action. I then give three arguments for the truth of the latter claim, which are also arguments for the truth of the former claim as I interpret it.

Jonas Olson writes that "a plausible moral error theory must be an error theory about all irreducible normativity". I agree. But unlike Olson, I think we cannot believe this error theory. I first argue that Olson should say that reasons for belief are irreducibly normative. I then argue that if reasons for belief are irreducibly normative, we cannot believe an error theory about all irreducible normativity. I then explain why I think Olson's objections to this argument fail. I end by showing that Olson cannot defend his view as a partly revisionary alternative to an error theory about all irreducible normativity.