When we act, we act for reasons. It is easy to hear this as a truism or platitude. “Surely,” it might be said, “what makes an action an action is the fact that it is something that someone does for a reason!” (Davidson 1963).

But in fact the claim that when we act, we act for reasons, is ambiguous. When interpreted in one way it is indeed a truism – all actions are things that people, or more generally animals, do for reasons – but, when interpreted in the other, it is no truism at all. Though some acts are done for reasons in this alternative sense, it isn't the case that all acts are done for reasons. Some people act because there is reason not to do what they do (Stocker 1979).

The claim that the term “reason” is ambiguous is, of course, familiar in the philosophical literature (Woods 1972; Smith 1987). On the one hand, talk of reasons is much the same as talk of causes. When we talk of reasons for action we thus sometimes have in mind the psychological states that teleologically and causally explain behaviour. This is the use of the word “reason” that is in play when I say that my reason for (say) tapping away on the keys of my laptop is that I want to write an introduction to my collection of essays and believe that something I can do – namely, tap away on the keys to my laptop – will lead to that outcome.