History of Western Philosophy - Bertrand Russell [78]
Nevertheless, the theory of ideas is not wholly abandoned. Without ideas, Socrates says, there will be nothing on which the mind can rest, and therefore reasoning will be destroyed. Parmenides tells him that his troubles come of lack of previous training, but no definite conclusion is reached.
I do not think that Plato's logical objections to the reality of sensible particulars will bear examination. He says, for example, that whatever is beautiful is also in some respects ugly; what is double is also half; and so on. But when we say of some work of art that it is beautiful in some respects and ugly in others, analysis will always (at least theoretically) enable us to say 'this part or aspect is beautiful, while that part or aspect is ugly.' And as regards 'double' and 'half', these are relative terms; there is no contradiction in the fact that 2 is double of 1 and half of 4. Plato is perpetually getting into trouble through not understanding relative terms. He thinks that if A is greater than B and less than C, then A is at once great and small, which seems to him a contradiction. Such troubles are among the infantile diseases of philosophy.
The distinction between reality and appearance cannot have the consequences attributed to it by Parmenides and Plato and Hegel. If appearance really appears, it is not nothing, and is therefore part of reality; this is an argument of the correct Parmenidean sort. If appearance does not really appear, why trouble our heads about it? But perhaps some one will say: 'Appearance does not really appear, but it appears to appear.' This will not help, for we shall ask again: 'Does it really appear to appear, or only apparently appear to appear?' Sooner or later, if appearance is even to appear to appear, we must reach something that really appears, and is therefore part of reality. Plato would not dream of denying that there appear to be many beds, although there is only one real bed, namely the one made by God. But he does not seem to have faced the implications of the fact that there are many appearances, and that this manyness is part of reality. Any attempt to divide the world into portions, of which one is more 'real' than the other, is doomed to failure.
Connected with this is another curious view of Plato's, that knowledge and opinion must be concerned with different subject-matters. We should say: If I think it is going to snow, that is opinion; if later I see it snowing, that is knowledge; but the subject-matter is the same on both occasions. Plato, however, thinks that what can at any time be a matter of opinion can never be a matter of knowledge. Knowledge is certain and infallible; opinion is not merely fallible, but is necessarily mistaken, since it assumes the reality of what is only appearance. All this repeats what had been said by Parmenides.
There is one respect in which Plato's metaphysic is apparently different from that of Parmenides. For Parmenides there is only the One; for Plato, there are many ideas. There are not only beauty, truth, and goodness, but, as we saw, there is the heavenly bed, created by God; there is a heavenly man, a heavenly dog, a heavenly cat, and so on through a whole Noah's ark. All this however, seems, in the Republic, to have been not adequately thought out. A Platonic idea or form is not a thought, though it may be the object of a thought. It is difficult to see how God can have created it, since its being is timeless, and he could not have decided to create a bed unless his thought, when he decided, had had for its object that very Platonic bed which we are told he brought into existence. What is timeless must be uncreated. We come here to a difficulty which has troubled many philosophic theologians. Only the contingent world, the world in space and time, can have been created; but this is the everyday world which has been condemned as illusory and also bad. Therefore the Creator, it would seem, created only illusion and evil. Some Gnostics were so consistent as to adopt this