The jnios, for example, defended that the diverse bodies were proceeding from an only substance. Tales it affirmed to be the water, the beginning of all the things; Anaximenes opposing itself it this conception, defended to be air and Anaximandro considered the indeterminate one, aperon. In the conception of both, the first element that gave to origin the multiplicity of beings, remains the same, under the variety of beings, because from it they derive and they converge everything, however, remaining the same. Giving to a new source the question of the reflection on the origin of the multiplicity of beings, I appeared in century VI B.C. a called philosopher Heraclitus de feso, whom even so it adopted as the jnios, a physical element, fire, as first cause of all the things, recognized that the identity of the primordial substance could not be kept, therefore devir was part of the essence of all the things. Therefore it affirms that nobody ' ' nobody can the same enter two times in river, therefore new waters always run ' ' (HERACLITUS apud BURNET, 2007, P. 154).
The change in its conception was the ticket of the opposite to another one, However, in way to this antagonism it has a harmony of the contrary that guarantees the order in the universe. In opposition Heraclitus, appears Parmnides de Elia, that breaching in radical way with the effective materialistic monismo and considering the Being as principle of all the things, deeply shakes the structures of cosmology, transforming it into certain way in a ontologia with the theory it To be. When defining the being as principle of all the things, Parmnides destroys the idea of devir, therefore in its vision not-to be it inexists, because admitting the existence of the changeability, would recognize the existence of not-being, therefore it would subtenderia that the being is proceeding from not-being by means of devir.