What are the odds of God existing?

The odds of being correct about God's existence (supposing you randomly selected your belief, which I don't think anyone does) may be 50/50, but that certainly doesn't show that there's a 50% chance of God existing. Either God exists, or doesn't: I'll give you that. However, given that there's no reason to assert either (God exists or God does not exist), there's no reason to assign equal probabilities (or any probabilities, really) to either event. It's incalculable.Now... Back to the argument... Another possibility is a necessary God who did not create the universe.Another possibility is a universe that was created by a God that no longer exists.As others have pointed out, a third possibility is that the universe simply exists and did not exist eternally. Correct me if I'm wrong, but electrons and positrons "poof" in and out of existence all the time with no apparent cause.I would also argue that the notion of cause and effect is time dependent, so creation (causing the universe to exist) would require time, which in of itself is a property of the universe. My head is spinning, so I'll stop here. Your argument has been demonstrated to be fallacious though, it seems.

Now who's doing the inductive reasoning? What about virtual particles?Also, cause and effect may only be a property of our universe. So, even if every event that occurs within the universe is caused, it doesn't necessarily apply to the universe itself.

I'll refer you to some good Wikipedia articles, they explain them better than I do.Quantum fluctuations, virtual particles, and the Casimir effect:Quantum fluctuation - Wikipedia
Virtual particle - Wikipedia
(Especially the part about pair production)
Casimir effect - WikipediaFor more on how these discoveries could point to an uncaused universe:CP violation - Wikipedia
Inflation (cosmology) - WikipediaThis is getting way off topic though.

Where do virtual particles come from then?