Page:Mind (New Series) Volume 12.djvu/18

 4 A. E. TAYLOR: particular, and is the cause by its " presence " of the qualities of the particular. In the Bepublic, where the supreme Idea is said to be even beyond truth and existence, as Mr. Benn reminds us, it is also said, as he does not remind us, that the sun in the visible world is the " offspring " of the " Good " "begotten in its own image," and the whole point of the immediately following metaphor of the divided line is to insist on the thorough-going connexion, continuity, and analogy of existence and experience, from the lowest to the highest levels. 1 It is surely an entire misreading of Plato's words when he is taken to mean only that the world of Ideas is not the world of things, or that perception is not knowledge. The positive connexion is at least as real in his view as the unlikeness. It is not in Plato that we, can find any countenance for the Indian notion that the things of sense are a mere illusory show. Our first step to a true insight into his meaning must be to set on one side this false and misleading antithesis of the immanent and the transcendent, which seems to make as much havoc of some recent Platonic exegesis as it does of metaphysics, if allowed to get a foothold there. Let me take a simple illustration which, besides exhibiting the worthlessness of this false antithesis, is adapted to lead us straight to the heart of Plato's thinking. It is a commonplace, or ought to be so, that the curves studied by the geometer are not as such accessible to sense-perception. The difficulty is not the merely mechanical one that you cannot actually draw a circle with all its radii exactly equal, a line of absolutely uni- form direction, etc. 2 If this were all the case of the geometer would not have all the interest which Plato rightly attributed to it for the general theory of science. For it may be said, though on measurement the radii of my circle might be found to be only approximately equal, and though their inequality might even be made directly apparent to the sense of sight by a magnifying glass, yet geometry deals with the forms of the visual world as they are directly presented in the visual perception, and hence, so long as the radii of my circle are visibly equal, the circle as seen is a true geometrical circle ; the circle as measured or as seen after magnification is in strictness not the same object, and therefore as a student of geometry I am not concerned with it. 3 The real problem 1 PhsedOj 100 d. Rep. 509 ff. 2 Though, of course, this difficulty among others is one of the problems which suggested to Plato the Ideal theory (Phtedo, 74). 3 This, I suppose, would be in principle the Kantian view of the nature of geometrical science.