If it were true, as Parmenides and Zeno claim, that the senses methodically and systematically report the fact of change, while the mind irrevocably denies its possibility, then the result is intellectual despair. There is no doubt that the controversy about change and motion between the school of Heraclitus and the school of Parmenides is at the root of that period of Greek thought known as the age of sophistry, when philosophers, having despaired of attaining the truth with their minds, discarded speculative philosophy, and used their intellects instead for the acquisition of power. It was Aristotle who contributed the right solution for the problem of change. A seed, Parmenides would say, either is or is not a tree. If the seed is a tree then it cannot change to one, because there is no change when things remain the same, but if the seed is not a tree, then neither can it change to one, because the being of a tree cannot arise from its non-being.
Potency is a reality and is different from sheer non-being which is nothing.
Change is the actualization of real potency in beings that are real but finite. We cannot leave the problem here without at least suggesting the way to solve the Zeno paradoxes. The fallacy of the paradox of Achilles and the tortoise consists in regarding as divided what is seen to be only divisible. Movement, time and distance, are different kinds of continuous quantities. Being continuous, each of them is immediately seen to be divisible ad infinitum .