Originally Posted by The_Heretic

I think their view of parallel universes is overly simplistic. The idea there's a copy of us assumes a narrower range of universal constants and probabilities than actually exist. Imagine where biological evolution could've gone but didn't. One more or less major asteroidal collision or one at a different time or of a different size or impact location and the entire history of live on Earth is different. And that's ignoring countless other factors affecting evolution.

Plus, there might well be a parallel universe where the Earth didn't form or a planet did the composition and size are different.

And then you have the unversal constant values for various forces. Any change down to the twenth decimal place and it all goes off some where else entirely.

Even with an infinite number of parallel universes I'm convinced that each of us is wholly unique.