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.