"Might this be a dream?" In this book, distinguished philosopher J. J. Valberg approaches the familiar question about dream and reality by seeking to identify its subject matter: what is it that would be the dream if "this" were a dream? It turns out to be a subject matter that contains the whole of the world, space, and time but which, like consciousness for Sartre, is nothing "in itself." This subject matter, the "personal horizon," lies at the heart of the main topics--the first person, the self, and the self in time--explored at length in the book.

The personal horizon is,...