 Another point to notice here is that the notion of things being determined thereafter is usually taken in an unlimited sense—i.e., determination of all future events, no matter how remote in time. But conceptually speaking, the world could be only imperfectly deterministic: things could be determined only, say, for a thousand years or so from any given starting state of the world. For example, suppose that near-perfect determinism were regularly (but infrequently) interrupted by spontaneous particle creation events, which occur only once every thousand years in a thousand-light-year-radius volume of space. This unrealistic example shows how determinism could be strictly false, and yet the world be deterministic enough for our concerns about free action to be unchanged.