 Let’s call a possible world ‘deterministic’ iff the thesis of determinism is true at that world; ‘non-deterministic’ iff the thesis of determinism is false at that world. There are two very different ways in which a world might be non-deterministic. A world might be non-deterministic because at least some of its fundamental laws are probabilistic, or a world might be non-deterministic because it has no laws or because its laws are not all-encompassing. Let’s call worlds which are non-deterministic in only the first way ‘probabilistic worlds’ and let’s call worlds which are non-deterministic in the second way ‘lawless’ or ‘partly lawless’ worlds.