This is obviously a tough question, as neither science nor religion have convinced me yet. I believe empirical evidence, so in the lack of such evidence I must ask myself (and you) on the prevalent theories: - Do you believe in the big bang? Did a big explosion happen from nothing? How does this reconcile with the laws of matter and thermodynamics? - Do you believe in God? If God created the universe, how was God created? Was he created at all? How can something that exists not have a beginning? I believe everything starts from something, so I have a hard time siding with either of these theories. Is it possible for the universe to always have existed, just evolved? How do we reconcile this with the linearity of time? I just wrote a lot to basically say: I dont know the answer to this one, and I havent formulated my own theory yet. If we havent been able to answer this questions in homo sapiens' entire existence, I doubt we will answer it before some kind of empirical evidence surfaces.