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. A. FIRST DIVISION. We here encounter the innate ideas of Descartes. The philosophy of Spinoza, in the second place, is related to the philosophy of Descartes as its necessary development only; the method is an important part of it. A method which stands alongside of Spinozism and which is also a perfected development of Cartesianism, is, in the third place, that by which Malebranche has represented this philosophy. 1. DESCARTES. René Descartes is a bold spirit who re-commenced the whole subject from the very beginning and constituted afresh the ground-work on which Philosophy is based, and to which, after a thousand years had passed, it once more returned. The extent of the influence which this man exercised upon his times and the culture of Philosophy generally, cannot be sufficiently expressed; it rests mainly in his setting aside all former presuppositions and beginning in a free, simple, and likewise popular way, with popular modes of thought and quite simple propositions, in his leading the content to thought and extension or Being, and so to speak setting up this before thought as its opposite. This simple thought appeared in the form of the determinate, clear understanding, and it cannot thus be called speculative thought or speculative reason. There are fixed determinations from which Descartes proceeds, but only of thought; this is the method of his time. What the French called exact science, science of the determinate understanding, made its appearance at this time. Philosophy and exact science were not yet separated, and it was only later on that this separation first took place.