The subject of this book is "metaphysics." Aristotle called it "first philosophy"; by this term he and St. Thomas Aquinas mean the full philosophical treatment of being and its Cause, of Being and God. Metaphysics begins with the beings of experience. Its preliminary concern is with the beings of direct experience, not with concepts, not with emotions or guesses (no matter how noble), not with some logical pre-conditions of experience (often dignified with the impressive term "a priori conditio ...