There are some perplexing mysteries in the way we look upon ourselves and our minds. We only identify ourselves with part of our minds. Why? We only feel we control part of what goes on in our minds. Why? Or, indeed, why any of it? What is this 'we', this 'I' that we feel we are, that we feel continues from one moment to the next, from one day to the next? How do we know anything about what is going on in our minds? These questions touch on the core issues of the psychological metaphysics of mind. Our concept of action, for example, rests upon an idea of «I» as an enduring substance, and moreover associates «I» distinctively with action, as opposed to behaviour of other kinds. This is basic to our understanding of ourselves and of our minds.