Phaedrus

PHAEDRUS: I quite admit, Socrates, that the art of rhetoric which these men teach and of which they write is such as you describe—there I agree with you. But I still want to know where and how the true art of rhetoric and persuasion is to be acquired.

SOCRATES: The perfection which is required of the finished orator is, or rather must be, like the perfection of anything else; partly given by nature, but may also be assisted by art. If you have the natural power and add to it knowledge and practice, you will be a distinguished speaker; if you fall short in either of these, you will be to that extent defective. But the art, as far as there is an art, of rhetoric does not lie in the direction of Lysias or Thrasymachus.

SOCRATES: All the great arts require discussion and high speculation about the truths of nature; hence come loftiness of thought and completeness of execution. And this, as I conceive, was the quality which, in addition to his natural gifts, Pericles acquired from his intercourse with Anaxagoras whom he happened to know. He was thus imbued with the higher philosophy, and attained the knowledge of Mind and the negative of Mind, which were favourite themes of Anaxagoras, and applied what suited his purpose to the art of speaking.

SOCRATES: Why, because medicine has to define the nature of the body and rhetoric of the soul—if we would proceed, not empirically but scientifically, in the one case to impart health and strength by giving medicine and food, in the other to implant the conviction or virtue which you desire, by the right application of words and training.