I've stumbled on the ontological argument without knowing that it's called that myself - not as an argument for god, but for multiple universes. Namely, one can conceive a universe so powerful that one of its properties is that it must necessarily exist, even if it doesn't yet and even if there is currently only one universe - a universe so powerful that it is capable of breaking the isolation inherent of a multiverse and will itself into existence.

I suppose you could argue for anything with this reasoning.