Determinism including every human decision and action, is the inevitable and necessary consequence of antecedent states of affairs. Determinism is a modern name for Democritus’ ancient idea that causal deterministic laws control the motion of atoms, and that everything – including human minds – consists merely of atoms in a void. It is usually understood to preclude free will because it entails that humans cannot act otherwise than they do. It holds that the universe is utterly rational because complete knowledge of any given situation assures that unerring knowledge of its future is also possible.