Full Idea
Causes are typically events, reasons are never events. You can give a reason by stating a cause, but it does not follow that the reason and the cause are the same thing.
Gist of Idea
Causes (usually events) are not the same as reasons (which are never events)
Source
John Searle (Rationality in Action [2001], Ch.4.I)
Book Reference
Searle,John R.: 'Rationality in Action' [MIT 2001], p.107
A Reaction
This is against Davidson. I'm with Searle here; my having a reason to do something is not the cause of my doing it. I don't, unlike Searle, believe in free will, but doing something for a reason is not just the operation of the reason.