[342a]
But concerning these studies I am minded to speak still more at length; since the subject with which I am dealing1 will perhaps be clearer when I have thus spoken. For there is a certain true argument which confronts the man who ventures to write anything at all of these matters, an argument which, although I have frequently stated it in the past, seems to require statement also at the present time.Every existing object has three things2 which are the necessary means by which knowledge of that object is acquired; and the knowledge itself is a fourth thing; and as a fifth one must postulate the object itself which is cognizable
1 Cf. Plat. L. 7.341c.
2 cf. Plat. Laws 895d, where Essence, Definition, and Name are enumerated; also Plat. Parm. 142a.