It searched clear and valid answers universally, but it believed that these answers could not be searched empirically? as they said the sofistas. They would have of being found in the reason. Thus, the bases of the truth and the virtuous behavior must be searched in our conscience. The man would need, first, to know it exactly itself (Cabral, 2006). He developed a method of search of the truth divided at two moments: irony and maiutica. For the irony it was recognized proper ignorance, and for the maiutica it could conceive proper ideas. This method was applied by means of dialogues in the squares of Atenas, of where it questioned the politics and the moral of there (Nunes, 1986). As punishment for having vexado the powerful ones in these dialogues carried through in the squares of Atenas, it was condemned to the death for the ingestion of cicuta (Bergman, 2004).

2.3PLATO Son of Athenian rich parents, was pupil notable of Scrates and suffered a great disillusion when its teacher was condemned to the ingestion of cicuta (Nunes, 1986). Its philosophical research, even so come back toward a practical and moral reality, if did not limit to the antropolgico field, as Scrates, but also the Metaphysical and cosmological field was extended to it (Cabral, 2006). To the forty years of age it established the Academy, where it conceived the Theory of Ideas. In accordance with Plato, the substance? Real? of the universe they are what it called of forms (ideas), and not it particular and physical manifestation ahead of our directions. These ideas would exist in a superior world, to the part of the perception human being (World of the Ideas, or Ideal). What we perceive by means of the five sensible ones it would be only the imperfect copy of these Ideas (Bergman, 2004). To demonstrate the acquisition of knowledge, it wrote the alegoria of the cave, in its book? The Republic.