is capable of gradual metamorphosis into love for the invisible and eternal. It is not only in the New Testament and the Prayer Book, in the _Divine Comedy_, Shakespeare’s _Sonnets_, and all great Romantic poetry that the results of this thinking are to be seen. Through the Church and the poets to the dramatist and the novelist, and through them to the common people—there is no soulful drawing-room ballad, no cinema-plot, no day-dream novelette or genteel text on the wall of a cottage parlour through which, every time the hackneyed word is brought into play, the authentic spirit of Plato does not peep for a moment forlornly out upon us. In the latter days of Plato’s life there came to the “Academy” where he taught a young man from Stagira, in Macedonia. His name was Aristotle, and after he left Plato he became for a time the tutor of Alexander the Great. In spite of their proximity in time and space, the difference between Plato’s method of thought and the Aristotelian or _peripatetic_ system can hardly be exaggerated. While Plato had concentrated his intellectual effort on mapping out what we should now call the “inner” world of human consciousness; starting from the point of view of ancient tradition and myth, and working outward; relating his thoughts to one another in accordance, as it were, with their own inherent qualities; and deducing the sense-world from the spiritual world; Aristotle turned to the acquisition of knowledge about the outer world of matter and energy—that is to say, that part of the world which can be apprehended by the five senses and the brain. The two philosophers were alike in their emphasis on the importance of cultivating immortality—or rather of “immortalling” (for they used a special verb which we have lost), but otherwise there were few resemblances indeed. To Plato the soul of the universe had seemed inseparable from his own soul, and natural phenomena such as the revolutions of the planets had interested him rather as tangible, outward pictures of the life within that soul. To Aristotle the world outside himself was interesting more for its own sake. Plato had looked up to “Ideas”—real Beings with an existence of their own, which stood behind physical phenomena rather than within them. Aristotle deliberately attacked this doctrine, maintaining that the Ideas were immanent; they could not have existed before visible Nature, nor could they have any being apart from it; and they could only be arrived at, he said, by investigating Nature itself. When Aristotle laid down his pen after writing the _Metaphysics_, the word _idea_ had taken a long step towards its present meaning.