This book is about the psychology of our freedom. By freedom I mean the freedom of alternative possibilities: the freedom to do things or not do them, or – as I shall also put it – control over whether we do those things or not. It is just this freedom that we think we possess in relation to much of our action. We ordinarily think that we are free, say, to go out in the evening or stay in – that it is within our control, or up to us, which of these actions we perform.

The Psychology of Freedom examines what sort of mind this freedom of action requires. It seeks to determine what mental capacities and states we need if we are to be free to act otherwise than as we actually do. In particular, the book examines what sort of will a free agent must possess. By the will I mean our capacity to determine in advance how we shall act through decision-making, thereby forming intentions about which actions we shall perform.

Much of the book discusses what goes on when we take a decision to act, and how the nature and rationality of our decisions relate to the nature and rationality of the actions which those decisions explain. This is because our ordinary conception of our freedom of action involves a conception of the will which is very demanding – and perhaps not even coherent. It is a controversial and unsolved problem what goes on in the decision-making by which we determine our actions. And this problem about the will is part of a wider problem about the nature of freedom itself.