Now oppose all this, all these peculiarities of the Platonic method, as we find it, to the exact and formal method of Aristotle, of Aquinas, of Spinoza, or Hegel; and then suppose one trained exclusively on Plato's dialogues. Is it the eternal certainty, after all, the immutable and absolute character of truth, as Plato conceived it, that he would be likely to apprehend? We have here another of those contrasts of tendency, constitutional [193] in the genius of Plato, and which may add to our interest in him. Plato is to be explained, as we say, or interpreted, partly through his predecessors, and his contemporaries; but in part also by his followers, by the light his later mental kinsmen throw back on the conscious or unconscious drift of his teaching. Now there are in the history of philosophy two opposite Platonic traditions; two legitimate yet divergent streams of influence from him. Two very different yet equally representative scholars we may see in thought emerging from his school. The "theory of the Ideas," the high ideal, the uncompromising demand for absolute certainty, in any truth or knowledge worthy of the name; the immediate or intuitive character of the highest acts of knowledge; that all true theory is indeed "vision":--for the maintenance of that side of the Platonic position we must look onward to Aristotle, and the Schoolmen of all ages, to Spinoza, to Hegel; to those mystic aspirants to "vision" also, the so-called Neo-Platonists of all ages, from Proclus to Schelling. From the abstract, metaphysical systems of those, the ecstasy and illuminism of these, we may mount up to the actual words of Plato in the Symposium, the fifth book of The Republic, the Phaedrus.