Becoming

Genesis (γένεσις) means coming-to-be, birth, origin — the process by which things come into existence; its companion is phthora, passing-away or destruction. Together, generation and corruption name the ceaseless flux of the natural world, where nothing simply is but everything is forever becoming and perishing. (The word lives on wherever we speak of the 'genesis' of something.)

Being against becoming

The contrast between being and becoming runs through the whole tradition. Parmenides denied genesis altogether, since being cannot arise from non-being. Plato answered by dividing reality: there is that which always is and never becomes — the Forms, objects of knowledge — and that which is always becoming and never is — the sensible world, object only of opinion. Becoming is the moving, mortal image of unchanging being.

A science of change

Aristotle devoted a treatise, On Generation and Corruption, to genesis as a distinct kind of change — not the mere alteration of qualities but the coming-to-be and passing-away of substances themselves, as the elements transform into one another. To explain how genuine novelty is possible, without conceding Parmenides' point that nothing comes from nothing, was one of the central tasks of his natural philosophy.