should therefore be a chief care of the state, in order that their spirit, though losing none of its peculiar energy, may yet be penetrated by reason. The best endowed by nature and culture among the warriors, may be selected at the age of thirty, and put upon a course of careful training. When he has reached the age of fifty and looked upon the idea of the good, he may be bound to actualize this archetype in the state, provided always that every one wait his turn, and spend his remaining time in philosophy. Only thus can the state be raised to the unconditioned rule of reason under the supremacy of the good. SECTION XV. THE OLD ACADEMY. In the old Academy, we lose the presence of inventive genius; with few exceptions we find here no movements of progress, but rather a gradual retrogression of the Platonic philosophizing. After the death of Plato, Speusippus, his nephew and disciple, held the chair of his master in the Academy during eight years. He was succeeded by Xenocrates, after whom we meet with Polemo, Crates, and Crantor. It was a time in which schools for high culture were established, and the older teacher yielded to his younger successor the post of instruction. The general characteristics of the old Academy, so far as can be gathered from the scanty accounts, were great attention to learning, the prevalence of Pythagorean elements, especially the doctrine of numbers, and lastly, the reception of fantastic and demonological notions, among which the worship of the stars played a part. The prevalence of the Pythagorean doctrine of numbers in the later instructions of the Academy, gave to mathematical sciences, particularly arithmetic and astronomy, a high place, and at the same time assigned to the doctrine of ideas a much lower position than Plato had given it. Subsequently, the attempt was made to get back to the unadulterated doctrine of Plato. Crantor is said to be the first editor of the Platonic writings. As Plato was the only true Socraticist, so was Aristotle the only genuine disciple of Plato, though often abused by his fellow-disciples as unfaithful to his master’s principles. We pass on at once to him, without stopping now to inquire into his relation to Plato, or the advance which he made beyond his predecessor, since these points will come up before us in the exhibition of the Aristotelian philosophy. (_See_ § XVI: III. 1.) SECTION XVI. ARISTOTLE.