Objection 1:
Illogical – to say that because something doesn’t have an effect on the place that you live in, it doesn’t exist…existence doesn’t work like that.
Also, some people think that split universes never fully decohere, and can continue to have slight effects on each other. There are experiments proposed to test this, though idk if they’ve done so yet.
It’s not completely illogical to claim that something exists even though it can’t and won’t have an effect on you, and I can explain why: if I program some sattelite in space to shoot out a single photon into space, and i point that photon into a part of the sky where no stars and galaxies are visible to our most powerful microscopes, then, given our current knowledge, it’s not irrational to say that that photon will continue to exist and continue to shoot out, even after we’ve lost contact with it and can no longer see any effects of it. After shooting out the photon, it won’t have an effect on us whatsoever, and yet it’s not illogical to think that it continues to exist. Why?
Well, it kinda works like this: not all unfalsifiable beliefs are irrational – the unfalsifiable beliefs that rest upon the implications made by other, falsifiable, beliefs are rational. We have significant evidence for object permanence, and the (usual) conservation of matter. If we assume those are true, we can assume that the photon we shot into space continues to exist, even if we can’t see any effect from it. To assume that the photon ceases to exist once it stops having an effect on us…well that assumption violates pretty much every law of physics. To falsify the idea that the photon continues to exist, you don’t point to the fact that it doesn’t have an effect – you’d have to falsify the laws of physics that imply its continued existence.
Likewise, many seem to think that MW is supported by many falsifiable beliefs, even if the existence of other universes isn’t itself falsifiable. And anyway, if the alternate you’s heard you saying they don’t exist, that might hurt their feelings. Be polite.
Objection 2:
This isn’t a problem for MW. The problem of first cause OR infinite regress is a problem for every single idea about how the universe started. Nobody knows the answer, not just ManyWorlders. Nobody knows the answer to that. Not even you.
Objection 3:
idk what you’re going on about.
Anyway, MW, as you know, isn’t completely proven, and I’m by no means an expert at defending it. If I happen to be unable to satisfy any of your questions, be aware, you and the audience, that that doesn’t falsify MW. I’m sure there are many valid reasons to be skeptical of MW. I just happen to find it compelling, and fun to talk about, and fun to argue for.