In ' ' Second Navegao' ' , Plato creates the theory of the ideas or the forms, and thus classic metaphysics appears. The dualism now is not contradictory, is dicotmico. The history of the division, the separation, the inferiorizao of the world of the appearances and the rise of the world of the ideas starts in the philosophy. The dualism now becomes ' ' vertical' ' , a side is imanente and another one transcendente, and a hierarchy is established in the relation. A clear influence of the thought of Parmnides and the polemizaes between this monista and the mobilistas exists in Plato. However, from Plato only it is that the division between essence and appearance loses the almost pudico respect that the poem of Parmnides kept. Metaphysics gains definitions clear and necessary, the hierarquizao places definitive values, the analogies approaches the Metaphysical concepts of the prxis, human acting, the ethics.
Aristotle over all develops a thought from a critical one in such a way to the philosophy of the daily pay-socrticos how much to the platonic philosophy, as we observe in Metaphysics, its main philosophical workmanship. The central point of critical of Aristotle the Plato consists of the rejection of the dualism represented for would have of the ideas. The relation that this assumes to exist between the intelligible world and the sensible one, composes what Aristotle configures as the paradox of the relation. If the relation is internal, not if it treats a dualism more than, if she is external is needed an infinite number of external points of interseco to effect it. None of the cases of the account to explain the relation between the intelligible world and the sensible one. To prevent this paradox, Aristotle tries to construct its metaphysics based on the real world, thus preventing the dualism of the two worlds. He claims then that everything what it exists substantiates is it individual, pertaining to the world concrete.