“The pattern is new,” T. S. Eliot has written, “at every moment”: for our past and the history of our culture forms a pattern for us, and each new step that we take implies a revaluation of all that has gone before. Professional philosophers are no longer much given to sayings of this sort; they leave it to poets to make them. Yet surely if these words apply anywhere they apply to the history of Philosophy. A new philosophy or a new position in Philosophy, genuinely new, involves the adoption of different categories, a new orientation; it involves the re-writing of its history and a changed outlook on a whole landscape of problems. The perspective is altered, we find; the masses re-group themselves and the relations fall differently into place.