Abstract
It has been argued by several writers that practical reasoning is capable of a kind of validity that is unlike the validity which theoretical reasoning can possess. One can gain an initial impression of this view's appeal, as well as of its content, by seeing how it could issue from analytical reflection upon the idea that actions, decisions and intentions all can be, and frequently are, reasonable . An inviting first step in such reflection is to say that for a certain intention, say, to be reasonable on a certain occasion is, roughly, for it to be true that a person could come to have that intention as a result of reasoning well about what to do. One might then add the further thought that, so far as regards what it is for a piece of reasoning to be well done, reasoning falls into at least two basic kinds: reasoning about what to do differs generically from reasoning about what is the case. The view which I mentioned at the outset can now be seen as a specific proposal regarding where this difference lies: reasoning about what to do has distinctive validity-conditions not shared by reasoning about what is the case.