acquaintance is not usually made with it when the Platonic writings are studied. Tennemann, for example, did not at all comprehend what was most important in the Platonic philosophy, and only gathered some of it together in the form of dry ontological determinations—for that was what he could comprehend. But it shows the greatest lack of intellect in a historian of Philosophy only to see in a great philosophic form whether there is anything yielding profit to himself or not. What we have thus to deal with in the dialectic of Plato is the pure thought of reason, from which he very clearly distinguishes the understanding (διάνοια), (_supra_, p. 47). We may have thoughts about many things—if indeed, we do have thought at all—but this is not what Plato means. Plato’s true speculative greatness, and that through which he forms an epoch in the history of Philosophy, and hence in the history of the world, lies in the fuller determination of the Idea; this extension of knowledge is one which some centuries later constituted the main element in the ferment which took place in universal history, and in the transformation which the human mind passed through. This fuller determination may, from what has gone before, be understood thus: Plato first comprehended the Absolute as the Being of Parmenides, but as the Universal which, as species, is also end, _i.e._ which rules, penetrates, and produces the particular and manifold. Plato, however, had not yet developed this self-producing activity, and hence often stumbled into an external teleology. As the union of the preceding principles, Plato further led this Being into determinateness and into difference, as the latter is contained in the triad of Pythagorean number-determinations, and expressed the same in thought. That is, he grasped the Absolute as the unity of Being and non-being—in Becoming, as Heraclitus says—or of the one and the many,[30] &c. He further now took into the objective dialectic of Heraclitus the Eleatic dialectic, which is the external endeavour of the subject to show forth contradiction, so that in place of an external changing of things, their inward transition in themselves, _i.e._ in their Ideas, or, as they are here, in their categories, has come to pass out of and through themselves. Plato finally set forth the belief of Socrates, which the latter put forward in regard to the moral self-reflection of the subject only, as objective, as the Idea, which is both universal thought and the existent. The previous philosophies thus do not disappear because refuted by Plato, being absorbed in him.