Many philosophers accept that ought implies can (OIC), but it is not obvious that we have a good argument for that principle. I consider one sort of argument for it, which seems to be a development of an Aristotelian idea about practical deliberation and which is endorsed by, amongst others, R. M. Hare and James Griffin. After briefly rehearsing some well-known objections to that sort of argument (which is based on the supposed pointlessness of impossible obligations), I present a further (...) objection, based on a maximally charitable reading of the argument, and conclude that nobody ought to think that it gives them a reason to accept OIC. (shrink)