The empirical changes in the conception of the eleata, did not pass of mere illusions. In the attempt to decide this shock between Parmnides and Heraclitus, Plato admitted the existence of two distinct realities: the intelligible world and the sensible one. In this devir would be present, because the proper experience proved, however, the sensible things only exist in function of that one, therefore is in function of the participation of the ideas, that the things are. Plato admitted, therefore, degrees in the being, to explain this to devir. The true being is the ideas, only objects of intelligence. The sensible things exist, but only reflected they are graduated of the authentic being.
Finally, Aristotle retakes the problematic one of devir that he was present in the reflections of the majority of its predecessors and solves the problem adopting the slight knowledge of act and power. From these concepts it develops its metaphysics. Formularization of the conception of Act and power Ahead of the multiplicity of beings, two questions are raised, will be that the being comes before the change or the change precedes the being? For Jolivet ' ' the being comes before the change (…) because all change implies the permanence of a citizen that, being before this or that, starts to be, after that, this or that without ceasing being he himself. ' ' (JOLIVET, 1972, P. 218), admitting the idea of the being as predecessor of the change, recognizes itself that the being cannot come from not-being, therefore of the nothing comes swims. Throughout devir the being is modified to remain the same, that is, understands this with the adoption of the slight knowledge of being in power, power to be, and to be in act, therefore what it precedes it is the being in power that will be changedded into act, without, however to leave of being a Being which the power determined already it.