A radical approach to the philosophy of mind, in which states of mind are identified with dispositions to behave in certain ways.The approach taken by Rowland Stout is a thoroughly up-to-date version of behaviourism, although not a form of behaviourism that denies the existence of consciousness, free will, rationality, etc., nor aims to reduce these to other sorts of things. Properly understood, the idea of being disposed to behave in a certain way is seen to be exactly as rich and interesting as the idea of being in a certain state of mind. The fact that our ways of behaving are sensitive to practical rationality is taken to be an essential aspect of our nature as conscious agents. And in describing such a version of practical rationality Stout claims we are describing the mental state of someone whose behaviour is sensitive to it.His account of behaviourism rests on two central notions—that of a causal disposition to behave and that of sensitivity to practical rationality. He explains and develops these notions in some detail, and then uses them to construct powerful and original accounts of belief, intention, knowledge, perception and consciousness.