Comment 12 by jinmane :

...if you were to run the universe again from the beginning, 13.7 billion years later I'd be sitting here typing this. Maybe then, nothing about this universe could possibly be any different... Isn't that a spooky idea? I think so :)

Although something like the Uncertainty Principle might rule this out, I have often speculated that if one knew the precise location and properties of all the subatomic particles (or whatever) present at the time of the Big Bang, and if one knew precisely how these particles interact with eachother, then it would be possible to build a simulation able to model every future occurrence in the universe, including every thought and action of living entities. I guess by definition one would need a computer more complex than the universe itself to achieve this, but if the future of the universe is indeed set in stone at the moment of the Big Bang, that sure would put an end to the theist's constant moaning about 'free will'.