Platão - os diálogos são mera propaganda de um modo de vida

"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.

If, in spite of these considerations, Plato still wrote dialogues, it was perhaps because he wanted above all to address not only the members of his school, but also absent people and strangers; for, as he said, "Written discourse goes rolling around in every direction. His dialogues can be considered as works of propaganda, decked out with all the prestige ofliterary art but intended to convert people to philosophy. Plato used to read them in the course of those sessions of public reading which, in antiquity, were the way to make oneself known. Yet the dialogues also spread far from Athens. Thus Axiothea, a woman from Phlius, read one of the books of the Republic and came to Athens to become Plato's student; ancient historians claimed she was long able to hide the fact that she was a woman. In a life of Plato which dates from the second half of the fourth century B.C., we find the following remark: "By composing his dialogues, he exhorted a mass of people to do philosophy; but he also gave many the opportunity to do philosophy in a superficial way." In order to convert people to this way of life called philosophy, however, some indication had to be given of what philosophy is. For this purpose Plato chose the dialogue form, primarily for two reasons. First, the literary genre of the Socratic dialogue, which presented Socrates himself as the primary interlocutor, was very fashionable at the time; and it was precisely the Socratic dialogue which allowed the ethical value of dialogue, as practiced in Plato's school, to be emphasized. 
It is reasonable to suppose that some of the dialogues convey an echo of what discussions within the Academy must have been like-though the character of Socrates, which is very vivid in the first dialogues, tends to become more and more abstract in the later dialogues, until it finally vanishes in the Laws. It must be admitted that this ironic, often ludic presence of Socrates makes reading the dialogues rather disconcerting for the modern reader, who reads them looking for Plato's theoretical "system." Compounding this difficulty are the numerous doctrinal inconsistencies which become evident when the reader moves from one dialogue to another.67 In the last analysis, all historians are obliged to admit-for different reasons-that the dialogues are an imperfect representation of what Plato's doctrine may have been; they "fall short of the Platonic philosophy" and "transmit to us only a particularly limited and impoverished image of Plato's activity within the Academy."
Victor Goldschmidt cannot be suspected of wanting to minimize the systematic aspect of Plato's doctrines; yet he proposed the best explanation of the aforementioned facts by saying that the dialogues were written not to "inform" people but to "form" them. Such was the deepest intention of Plato's philosophy. He did not aim to construct a theoretical system of reality, and then "inform" his readers of it by writing a series of dialogues which methodically set forth this system. Instead, his work consisted in "forming" people-that is to say, in transforming individuals by making them experience, through the example of a dialogue which the reader has the illusion of overhearing, the demands of reason, and eventually the norm of the good.
From this perspective of formation, the role of the written dialogue consists primarily of learning how to practice the methods of reason, both dialectical and geometric, which will enable the student to master the arts of measure and definition in every domain. This is what Plato hints with regard to the long discussion which he introduces in the Statesman: 
"In classes where people learn to read, when the student is asked which letters go to make up such-and-such a word, do we say that he undertakes this investigation only so that he can be brought to resolve one problem, or in order to make him more apt at solving all possible grammatical questions?"
"All questions, obviously."
"What then shall we say about our investigation on the subject of the 'statesman'? Has it been undertaken out of interest solely in this topic, or rather so that we may become better dialecticians on all possible subjects?"
"Here again, obviously, it is so that we may become better dialecticians on all possible subjects."
"To find the solution to the problem proposed in the easiest and quickest way possible ought to be only a secondary preoccupation and not a primary goal, if we are to believe reason, which orders us to accord our esteem and the first rank to the method itself."
This is not to say that the dialogues may not also have had some doctrinal content, since they usually pose a precise problem and propose, or try to propose, a solution to it. Each one forms a coherent whole, but they do not necessarily cohere with one another. What is remarkable is that several dialogues-the Parmenides and the Sophist, for instance-deal with the conditions on which dialogue itself is founded. They try to render explicit all the presuppositions implied by the ethics of the true dialogue-that is to say, within the Platonic choice of way oflife. In order for the interlocutors to get along-better yet, in order for them to get along while choosing the good-the existence of "normative values" must be supposed. Independent of circumstances, conventions, and individuals, these values underlie the rectitude and rationality of discourse: 
"Imagine that one refuses to determine for each object of discussion a definite Form or Idea. Then one will not know where to turn one's thought, since one will not have wanted the Idea of each being to be always the same. Then the possibility even of discussion will be annihilated."
The affirmation of the Forms is thus inherent to every dialogue worthy of the name. At this point, however, there arises the problem of how they are known-it cannot be through the sensesand of how they exist, for they cannot be sensible objects. Plato was thus brought to propose his theory of intelligible, or nonsensible, forms; and he was consequently dragged into the problems posed by their existence and their relations with sensible things. Plato's philosophical discourse was based on a willing choice to engage in dialogue, and therefore on the concrete, lived experience of spoken, living dialogue. It bears essentially upon the existence of immutable objects, or nonsensible Forms, which guarantee the rectitude of discourse and action; but also upon the existence within human beings of a soul, which, more than the body, ensures the individual's identity. As we see from most of the dialogues, moreover, these Forms are first and foremost moral values, which serve as the foundation for our judgments on things concerning human life. Above all, what is important is to try to determine, thanks to a study of the measure proper to each thing, the triad of values within the life of the city and the individual. This triad appears throughout the dialogues: that which is beautiful, that which is just, and that which is good. Like Socratic knowledge, Platonic knowledge is, above all, a knowledge of values.
Rene Schaerer wrote that "the Essence of Platonism is and remains supradiscursive." What he meant was that the Platonic dialogue does not say everything. It does not say what the Norms are, or the Forms, or Reason, or the Good, or Beauty; for all these things are inexpressible in language and inaccessible to any definition. One experiences them, or shows them in dialogue and in desire; but nothing can be said about them."
Pierre Hadot, "What is Ancient Philosophy?"