It is not easy to explain how people know what they are going to do. The phenomenon occurs: obviously we often do know what we are going to do; but its explanation is less obvious. When I say this, I do not mean that we have some mysterious method by which we discover what we are going to do, like forecasting tomorrow's weather. Usually we know without any investigation, and without the use of any method of discovery. You know some of the things that you are going to do tomorrow immediately – i.e. you know them without the mediation of any evidence. This is a rather mysterious phenomenon, and it is not at all easy to classify it. How is it possible for there to be any immediate knowledge of something which lies in the future? Is it like the kind of immediate knowledge of the past which is supplied by memory? If so, does this analogy help us to understand our knowledge of our own future actions? Or is memory equally mysterious?