In my campaign different religions and philosophies have different stories regarding the existence of the world. The "truth", as far I am concerned, is that the Cosmos is a purposeless and accidental bubble floating in the midst of infinite Chaos. Intelligent beings evolved naturally in the Cosmos, and through the focus of their will are able to shape the laws of the Universe through controlled introduction of the Chaos into the Cosmos (hence magic). The gods did not exist before intelligent created them through worship, and once a god is no longer worshiped they "die" (but can be reborn through renewed worship). The gods do not know this fact, and remember creating the Universe in various ways (but that belief is false). Divine miracles are really just magic worked under different circumstances.