There is no probability. No rolling dice. It is every combination of everything. I know Hilberts infinite hotel, I know (enough about) probability and statistics.

I am talking about the multiverse that many people imagine. The one where you can say “there is a universe in which I am president. And one where Lincoln is a velociraptor, and a universe where chairs sit on people instead of the other way round”. In that multiverse, I can construct a universe without triangles that is identical to another universe with triangles in every regard except for the existence of triangles. And I can do that for every universe with triangles. Its a bijection.

We dont permute a (in)finite set of initial parameters and then evolve the universe from there, we have a universe for every CURRENT state.

In the hypothetical reality where such a multiverse exists (it would be a case of Russells paradox as OP has discovered), there is a 50% chance to be in a universe where it doesn’t.

I know. But I case of the multiverse that many people think about, the one where there is a universe for EVERYTHING, there will be exactly as many universes where triangles exist as there are universes where triangles dont exist. And the same is true for everything else.

And it is exactly the same number, not just the same type of infinity. Because for every universe with triangles there must also exist the exact same universe without triangles (and vice versa), otherwise the multiverse wouldn’t contain all possible universes.

If there are infinite universes, covering all permutations of all properties (i asume thats what they mean by omniverse), then there will be exactly as many universes with a certain property then there are without it. So it is actually 50/50.

In the “multiverse of all possibilities” there will be 50% without a multiverse