Thus much at least, I can say about all writers, past or future, who say they know the things to which I devote myself, whether by hearing the teaching of me or of others, or by their own discoveries-that according to my view it is not possible for them to have any real skill in the matter. There neither is nor ever will be a treatise of mine on the subject. For it does not admit of exposition like other branches of knowledge; but after much converse about the matter itself and a life lived together, suddenly a light, as it were, is kindled in one soul by a flame that leaps to it from another, and thereafter sustains itself.
— Plato, Seventh Letter, J. Harward translation.
I want to discuss a feature of ancient Greek thinking that is certainly alien to the metaphysical presuppositions of our age: namely, that mind/nous is not a faculty of our individual minds but a single, transcendent, common ground on/toward which our various intellects participate/relate. As thinkers we participate in it as much as we do our environing physical world. While each of us may hold distinct opinions about this or that, different knowers know the same thing and not just identical replicas of the same thing. Knowers live in a common (zynon) world, joined as they are to a common mind.
Think for a moment of how we might communicate the meaning of a word like “banana” to someone who doesn’t speak the language: Tarzan, let’s say. We would hold up the common object, the physical banana, pronounce the word “banana” and hope that Tarzan grasps the link between word and thing. A hard matter to accomplish, but certainly possible. Now, imagine trying to communicate the meaning of the word without the physical banana present in common between us. Try to teach Tarzan over the telephone without common access to a world of things. Now we can say “banana” to our heart’s content and never advance one iota toward communication. An ability to communicate presupposes commonality: either the commonality of objects between two people who don’t share a language or the commonality of language (which itself must originate in a common world.)