I explicate and defend leibniz's argument from "eternal truths" to the existence of god. I argue that necessary beings can be caused to exist, Showing how one can apply a counterfactual analysis to such causation, Then argue that if such beings can be caused to exist, They are.

According to David Lewis, we all believe there are countless ways in which things might have been different from the way they are in fact. Surely, for example, the world could have existed even if, say, Quine had been a politician, or if there had been one less page in Word and Object, or indeed if there had been no such person as Quine at all. All these things, we are inclined to think, might have been the case. And thus (...) we find ourselves saying, “There are many ways things could have been.” However, as Lewis notes, this sentence involves an existential quantification over objects of a peculiar sort: “ways things could have been”—”possible worlds,” if you like. At face value, then, our modal discourse commits us to belief in possible worlds—as peculiar as that may seem. Those who feel squeamish at this prospect can perhaps console themselves with the fact that failure to believe in real, live alternate possibilities ends in Spinozism: the view that (in Samuel Clarke’s words) “nothing which is not, could possibly have been; and nothing which is, could possibly not have been; and that no mode or circumstance of the existence of anything could possibly have been in any respect otherwise than it now actually is.” For most of us, I dare say, this is a difficult pill to swallow. (shrink)

When I profess realism about possible worlds, I mean to be taken literally. Possible worlds are what they are, and not some other thing. If asked what sort of thing they are, I cannot give the kind of reply my questioner probably expects: that is, a proposal to reduce possible worlds to something else. I can only ask him to admit that he knows what sort of thing our actual world is, and then explain that possible worlds are more things (...) of that sort, differing not in kind but only in what goes on at them. (shrink)