A truth must be always called into question and you can only do it through dialogue, in oral form, because what is written does not change. The script does not respond to questions posed by the interlocutor and this nullifies the value of philosophical dialogue where the two parties together are seeking the truth, with each other's questions and answers
Plato was wary in communicating his ideas in writing. In ancient Greece in fact the preferred way to display any kind of knowledge was the spontaneous use of oral communication. When the written transmission appeared, this assumed the function of fixing thoughts synthetically in order to make storable in the memory a new content of knowing. Until the fifth century, when the sophists appear masters of rhetoric, the poetic expression was certainly superior to prose, more suitable for expressing abstract thoughts. Even afterwards, however, as in the Hellenistic and late imperial age the use of the verse was not completely abandoned.
Another widely used kind of philosophical communication of ancient times was the epistle, usually directed at an acquaintance or friend of the writer, and in that it was often initially private. Moreover, the ancients were reluctant to publish letters about their private and intimate life and then the epistle gradually assumed for philosophical considerations the value of being taken besides the readers.
Plato in his Letter VII seems to support positions similar to those of his teacher Socrates on the limits of writing but it looks even to anticipate certain interpretations of the value of the communication of existence found in Kierkegaard when saying that he will hide his personal convictions about "things that were given thought" since it is difficult to understand if not in contact with existential dialogue rather than in writing. "However, this I can say on behalf of all those who have written or will write to know things that I think, both for having heard me, and having them heard by others or for having discovered for themselves: I believe impossible that they have understood anything of that subject. On these matters there is no my writing nor will there ever be [...] For this reason, no one who has good sense will dare to commit his own thoughts to such a means of expression, to an immobile way of communication, as they are precisely the words set out in characters of writing. "
Plato's solution was to keep the expression in prose in the philosophical discourse, but at the same time recover the artistic aspect by introducing the literary form of dialogue and especially the use of myth. Plato will try to recover the poetic wisdom within philosophy; Aristotle instead, breaking all relations with poetry, thought that in the philosophical discourse philosophy would only be rational and specialized.
The problem prevailing from Socrates onwards was not so much to give or not an artistic garment to the philosophical thought, but if the communication should be submitted orally or in writing.
Plato in fact was in disagreement with his teacher Socrates who had never wanted to state his thoughts in writing because the written word is like "a bronze that being struck gives always the same sound." The script did not respond to questions of the interlocutor and this nullified the value of philosophical dialogue where the two parties together are seeking the truth with each other's questions and answers. A truth that must also be called into question and that is possible only through dialogue, in the oral form, because what is written does not change.
So, there are two opposing needs: that of Socrates who aspires to a philosophizing open and evolving, leading to the conviction of the interlocutor, but that remains imprecise in colloquial language and not well defined in its terms, and that of Plato adopting a closed system of doing philosophy which does not allow immediate answers because what he says has long been considered and determined in the certainty of the written words and mainly because what they receive is unchanging truths that comes from the "world of ideas". A way of philosophizing that of Plato more accurate but, in a sense static. It is no coincidence that in the Platonic ‘production’ the Socratic dialogue form of his writings, present in the early works, is progressively abandoned in maturity: the figure of Socrates loses more and more importance and the dialogue is reduced to a monologue, a dialogue, as has been said, of the soul with itself.