Now, about speaking and hearing perfectly and usefully — let's drop that topic for now if you don't mind. We're both nowhere near that level. But I think everyone will agree on this: if you're going to listen to philosophers, you need some practice in listening. Right? So why aren't you saying anything to me? Here's all I can tell you: If you don't know who you are, why you exist, what this world is, who you're dealing with, what's good and bad, what's beautiful and ugly — if you can't understand arguments or proof, can't tell truth from lies, can't make distinctions — then you won't want the right things or avoid the right things. You won't move toward what you should or plan properly. You won't agree, disagree, or hold off judgment when you should. To put it simply: you'll stumble around deaf and blind, thinking you're somebody important when you're actually nobody.
Now as to speaking and hearing perfectly, and usefully, let us for the present, if you please, say no more, for both of us are a long way from everything of the kind. But I think that every man will allow this, that he who is going to hear philosophers requires some amount of practice in hearing. Is it not so? Why then do you say nothing to me? I can only say this to you, that he who knows not who he is, and for what purpose he exists, and what is this world, and with whom he is associated, and what things are the good and the bad, and the beautiful and the ugly, and who neither understands discourse nor demonstration, nor what is true nor what is false, and who is not able to distinguish them, will neither desire according to nature nor turn away nor move towards, nor intend (to act), nor assent, nor dissent, nor suspend his judgment: to say all in a few words, he will go about dumb and blind, thinking that he is somebody, but being nobody.