Philosophy, unlike most other subjects, does not try to extend our knowledge by discovering new information about the world. It tries to deepen our understanding by reflection on what is already closest to us—the experiences, thoughts, concepts, and activities that make up our lives, and that ordinarily escape notice because they are so familiar. Philosophy begins by finding utterly mysterious the things that pervade our everyday lives, such as language, perception, value, and truth. For everyday purposes we don’t have to know how these things are possible: we talk, we see what is in front of us, and we judge that this action is wrong or that assertion true. But it is possible, in the tradition deriving from Plato, to stop and think about what we are really doing, not for a practical purpose but just in order to understand what lies beneath the familiar surface of life.
Human consciousness, which is at the core of everything we do and think, is one of the principal targets of such philosophical understanding. In our time the advance of physical and biological science makes possible the search for some of its physiological conditions, but there is a more basic understanding of consciousness that remains a philosophical task, and that is surprisingly undeveloped—an understanding that we can pursue only from within. It has occupied phenomenologists like Husserl and Sartre, and empiricists like Hume and Russell. Even if empirical science starts from the evidence provided by conscious experience, understanding the nature of that starting point is still mainly the concern of philosophers.
Brian O’Shaughnessy’s philosophical career has been occupied with our most basic relations to the world. Twenty years ago he published another enormous book called The Will, about how we connect to the world in the outward direction, when we act. His new book, going in the other direction, examines the world’s impact on us through perception—though he emphasizes that we are anything but passive when we perceive the world around us; that, too, involves the will.
O’Shaughnessy’s approach to perceptual consciousness is distinctive in being simultaneously physical and phenomenological. He takes us and other animals to be physical beings—parts of the physical world—each of which has a perspective on that world and an inner life of some kind. An inquiry into conscious experience cannot be based merely on the observation of external behavior; but it also cannot be carried out in abstraction from our physical nature. The understanding of the inner life of the person who is conscious must include the physical body from the start. In his new book O’Shaughnessy develops an account of human consciousness as a continual process by which we come to know about the vast physical world around us through awareness of what is going on in a small part of it, namely our own body.
It could hardly be otherwise, since all information about the rest of the world reaches us through our bodies …