Leibniz, Reid, Brentano and many other philosophers have held that, by considering certain obvious facts about ourselves, we can arrive at an understanding of the general principles of metaphysics. The present book is intended to confirm this view. One kind of philosophical puzzlement arises when we have an apparent conflict of intuitions. If we are philosophers, we then try to show that the apparent conflict of intuitions is only an apparent conflict and not a real one. If we fail, we may have to say that what we took to be an apparent conflict of intuitions was in fact a conflict of apparent intuitions, and then we must decide which of the conflicting intuitions is only an apparent intuition. But if we succeed, then both of the intuitions will be preserved. Since there was an apparent conflict, we will have to conclude that the formulation of at least one of the intuitions was defective. And though the formulation may be imbedded in our ordinary language, we will have to say that, strictly and philosophically, a different formulation is to be preferred. But to make it clear that we are not rejecting the intuition we are reformulating, we must show systematically how to interpret the ordinary formulation into the philosophical one. The extent to which we can show this will be one mark our success in dealing with philosophical puzzle. Another will be the extent to which our proposed solution contributes to the solution of still other philosophical puzzles.