When you hear theoretical physicists talk about an infinite universe, or the concept of a multiverse, they always consider the possibility of worlds which are strikingly similar to ours but which vary in a single or very few details.  Maybe on this Earth you wear your favourite pair of green socks with the orange heels and toes every Thursay, but on some other planet an individual exactly like you wears an identical pair of socks — right down to the rapidly thinning patch on the bottom of the big toe — except this individual wears those socks every Wednesday.  Or whatever.

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