I'll disagree with Tangle in this one respect.

If we consider we live in an infinite universe then there are an infinite number of "spaces" in that universe. Each space must have a number of particles within it which is finite and thus a number of configurations for those particles in that space which is also finite. The number of particles and number of configurations will be very large but they both will be finite. In an infinite universe of infinite spaces there must be a space where the number of particles and their configuration is exactly the same as any specific space you so choose.

If the space we choose is our own space, our known "universe" as we see it, then in an infinite universe there must be another such space of exactly the same number of particles in exactly the same configuration as we see here. An identical "universe" to our own. And, infinities being what they are, there are an infinite number of such "universes" identical to our own. And an infinite subset of those infinite universes like our own will have the exact same histories, past, present and future.

*Edited by AZPaul3, : No reason given.*