Earlier versions of various parts of this book have been delivered as shorter series of lectures, or as individual lectures at many other universities over a number of years; and the book has, I hope, benefited by the wealth of helpful criticism which I received on these occasions. Part of Chapter 14 was delivered, under the title ‘The Structure of the Soul’, as my Inaugural Lecture as Nolloth Professor of the Philosophy of the Christian Religion in the University of Oxford. Versions of certain parts of the book have received prior publication in various forms. My contribution to a book co-authored with Sydney Shoemaker, Personal Identity (Basil Blackwell, Oxford, 1984) was a fuller version of the ideas contained in Chapters 8 and 9 of the present book. Some passages of Chapter 7 are reprinted from my Faith and Reason (Clarendon Press, Oxford, 1981). Recent articles which are earlier or fuller versions of other material are: ‘Are Mental Events Identical with Brain Events?’, American Philosophical Quarterly, 1982, 19, 173–81; and three articles being published in 1985–6, ‘The Indeterminism of Human Actions’ (in Midwest Studies in Philosophy, vol. 10), ‘Thought’ (in Philosophical Studies, © 1985 by D. Reidel Publishing Co.), and ‘Desire’ (in Philosophy). I am grateful to the publishers of the books and editors of the journals concerned for permission to reuse the various materials.

My writing of this book was greatly facilitated by the University of Keele giving me study leave from my position there as Professor of Philosophy for two terms of 1982–3; I am very grateful for the relief which was provided thereby from normal teaching and administrative duties.