The Republic by Plato Part 6 Page 31

cries, and by what sounds, when another utters them, he is soothed or infuriated; and you may suppose further, that when, by continually attending upon him, he has become perfect in all this, he calls his knowledge wisdom, and makes of it a system or art, which he proceeds to teach, although he has no real notion of what he means by the principles or passions of which he is speaking, but calls this honourable and that dishonourable, or good or evil, or just or unjust, all in accordance with the tastes and tempers of the great brute.

Good he pronounces to be that in which the beast delights and evil to be that which he dislikes; and he can give no other account of them except that the just and noble are the necessary, having never himself seen, and having no power of explaining to others the nature of either, or the