> I've heard it said...

That sounds like the sort of sounds-cool concept that's often founded in popularized / kinda-sensationalized / as-understood-by-a-philosopher "science".

If one makes a bunch of carefully chosen, arbitrary assumptions about an infinite universe, then there could be quite a few copies of you out there. But I can make a few carefully chosen assumptions about this universe, and conclude that 999 invisible copies of you are hiding in my living room right now. And listening to my noisy keyboard as I type these words, and...

More realistically - there are a huge number of ways for the universe to be infinite...yet contain zero copies of you. But such dull facts don't get nearly as many clicks, so you hear less about them.

Well, as I understand it: imagine there is a world consisting of only 20 numbers: 34, 56, 79, 11, 32 and so on. With that 20 numbers we can describe that world, its current state, we can replicate it. And there is a creature that lives in that world, we can describe it with three numbers, and the world numbers contains that numbers of the creature. Now imagine, it turns out the world does not consist of 20 numbers, but of billions of numbers, imagine how many exact copies of that creature in that world of billions of numbers just by accident, and maybe even exact or almost exact copies of that world of 20 numbers.

That may be /one/ (near-) infinite universe which duplicates.

But it does not support the conjecture in question, that /any/ infinite universe must duplicate.

The set of positive integers is infinite. It has no duplicates.

The point is picks from it can duplicate.

Sounds like the start of a proof by contradiction that the universe is not infinite, merely very, very, very large :)

I agree. Sounds wrong. May we see the source?

If it can happen in this universe, and the universe is infinite, then there are an infinate number of duplicates. This doesn't mean they would be "like" you, they occupy a different time/space and thus would be a independent entity.

A set being infinite does not mean that it contains everything. For example, the set of even integers is infinite but does not contain the number 3. So even if the universe is infinite, that does not mean that it contains another copy of you, or anything else in particular.