I shall focus this discussion on one small thread in the increasingly complex weave of Artificial Intelligence and Philosophy of Mind: the attempt to explain how rational thought is mechanically possible. This is, historically, the crucial place where Artificial Intelligence meets Philosophy of Mind. But it is, I shall argue, a place in flux. For our conceptions of what rational thought and reason are, and of what kinds of mechanism might explain them, are in a state of transition. To get a sense of this sea change, I shall compare several visions and approaches, starting with what might be termed the Turing-Fodor conception of mechanical reason, proceeding through connectionism with its skill-based model of reason, then moving to issues arising from robotics, neuroscientific studies of emotion and reason, and work on “ecological rationality”. As we shall see there is probably both more, and less, to human rationality than originally met the eye.