"Up to now, we have spoken solely of oral dialogue as it must have been practiced within the Academy. We can only imagine what this dialogue must have been like, by means of the examples we find in Plato's written work; and in order to simplify things, we have often quoted them using the phrase "as Plato says." Yet this expression is quite inexact, for Plato, in his written works, never says anything in his own voice. Whereas Xenophanes, Parmenides, Empedocles, the Sophists, and Xenophon had not hesitated to write in the first person, Plato makes fictional characters speak within fictional situations. Only in the Seventh Letter does he allude to his philosophy, and when he does he describes it more as a way of life. Above all, he declares that with regard to the object of his concerns, he has not published any written work, nor will he ever do so, for the knowledge in question cannot under any circumstances be formulated like other bodies of knowledge. Instead, it springs forth within the soul, when one has long been familiar with the activity in which it consists and has devoted one's life to it.
We might wonder why Plato wrote dialogues, for, in his view, spoken philosophical discourse is far superior to that which is written. In oral discourse, there is the concrete presence of a living being. There is genuine dialogue, which links two souls together, and an exchange in which, as Plato says, discourse can respond to the questions asked of it and defend itself. Thus, dialogue is personalized: it is addressed to a specific person, and corresponds to his needs and possibilities. Just as, in agriculture, it takes time for a seed to germinate and develop, many conversations are necessary for knowledge to be born in the soul-knowledge which, as we have seen, will be identical to virtue. Dialogue does not transmit ready-made knowledge or information; rather, the interlocutor conquers his knowledge by his own effort. He discovers it by him-self, and thinks for himself. Written discourse, by contrast, cannot respond to questions. It is impersonal, and claims immediately to give a knowledge which is ready-made, but lacks the ethical dimension represented by voluntary assent. There is no real knowledge outside the living dialogue.