Max Tegmark observed that we have three independent reasons to believe we live in a Big World: A universe which is large relative to the space of possibilities. For example, on current physics, the universe appears to be spatially infinite (though I'm not clear on how strongly this is implied by the standard model).

If the universe is spatially infinite, then, on average, we should expect that no more than 10^10^29 meters away is an exact duplicate of you. If you're looking for an exact duplicate of a Hubble volume - an object the size of our observable universe - then you should still on average only need to look 10^10^115 lightyears. (These are numbers based on a highly conservative counting of "physically possible" states, e.g. packing the whole Hubble volume with potential protons at maximum density given by the Pauli Exclusion principle, and then allowing each proton to be present or absent.)

The most popular cosmological theories also call for an "inflationary" scenario in which many different universes would be eternally budding off, our own universe being only one bud. And finally there are the alternative decoherent branches of the grand quantum distribution, aka "many worlds", whose presence is unambiguously implied by the simplest mathematics that fits our quantum experiments.

Ever since I realized that physics seems to tell us straight out that we live in a Big World, I've become much less focused on creating lots of people, and much more focused on ensuring the welfare of people who are already alive.

If your decision to not create a person means that person will never exist at all, then you might, indeed, be moved to create them, for their sakes. But if you're just deciding whether or not to create a new person here, in your own Hubble volume and Everett branch, then it may make sense to have relatively lower populations within each causal volume, living higher qualities of life. It's not like anyone will actually fail to be born on account of that decision - they'll just be born predominantly into regions with higher standards of living.

Am I sure that this statement, that I have just emitted, actually makes sense?

Not really. It dabbles in the dark arts of anthropics, and the Dark Arts don't get much murkier than that. Or to say it without the chaotic inversion: I am stupid with respect to...

Braden

Braden

Braden

Braden