Abstract
Professor Armstrong defends the view ‘that mental states are nothing but physical states of the brain’. He is aware that it is not humanly possible to prove such an identification. But he feels that it is possible to show that the philosophical and logical objections formulated against it are not valid; possible, also, to refute rival philosophical views and to reach a point where one gives a reasonably complete explanation of all mental states in physical terms. The completeness of the explanation would not prove its truth but would give it force and value. Accordingly, the major part of the book is an attempt ‘to give an account of all mental states as states of the person apt for the bringing about of certain sorts of physical behaviour’.