A. Introductory PLATO believed in something that we may vaguely call a rational order. Without this rational order the world would be a chaotic place. It is therefore important to know the rational order. Conceiving of knowledge to some extent after the model of acquaintance, Plato would naturally think of knowing the rational order in terms of knowing its various components. He would therefore think it important to come to know beauty, triangularity, equality, justice and the other things which constitute the rational order. The criterion of knowing beauty would naturally be the ability to say what it is. Therefore it would be essential, for every important value of X, to be able to say what X-hood is.