G. W. F. Hegel: Lectures on the History of Philosophy
Table of Contents

METAPHYSICS is what reaches after substance, and this implies that one unity, one thought is maintained in opposition to dualism, just as Being was amongst the ancients. In metaphysics itself we have, however, the opposition between substantiality and individuality. What comes first is the spontaneous, but likewise uncritical, metaphysics, and it is represented by Descartes and Spinoza, who assert the unity of Being and thought. The second stage is found in Locke, who treats of the opposition itself inasmuch as he considers the metaphysical Idea of experience, that is the origin of thoughts and their justification, not yet entering on the question of whether they are absolutely true. In the third place we have Leibnitz's monad - the world viewed as a totality.