In response to what I THINK you said, I would say this: The probability of this conversation repeating itself, in any large number of universes, any number at all, anything short of infinity, is probability zero. But in an infinite number of universe, it is probably certain.Hornbein said:Imagine two parallel perfect laser beams. If they stay parallel forever we say the Universe is flat. Calling it "straight" might have been better, but that's what we've got. If the beams converge then the Universe is spherical. If they diverge then U is hyperbolic.
As to that stuff about the conversation going on an infinite number of times I don't take that seriously. I'd say this comes up from people who don't know measure theory. To make a long story short, probability zero is not the same as impossible. I expect that in an infinite Universe your conversation has probability zero.
Basic measure theory is quite simple, it's just abstract and not widely taught. Suffice to say that all finite subsets of an infinite set have measure zero. Even an infinite subset may or may not have measure zero.