It has been argued that in a deterministic universe, no one has any reason to do anything. Since we ought to do what we have most reason to do, no one ought to do anything either. Firstly, it is argued that an agent cannot have reason to do anything unless she can do otherwise; secondly, that the relevant ‘can’ is incompatibilist. In this paper, I argue that even if the first step of the argument for reason incompatibilism succeeds, the second (...) one does not. It is argued that reasons require alternative possibilities, because reasons are action-guiding. A supposed reason to do the impossible, or to do what was inevitable anyway, could not fill this function. I discuss different interpretations of the claim that reasons are action-guiding, and show that according to one interpretation it is sufficient that the agent believes that she has several alternative options. According to other interpretations, the agent must really have alternative options, but only in a compatibilist sense. I suggest that an interpretation of action-guidance according to which reasons can only guide actions when we have several options open to us in an incompatibilist sense cannot be found. We should therefore assume that reasons and obligations are compatible with determinism. (shrink)