I suspect that what you're referring to as "MWI" contains the idea that, in addition to a wavefunction evolving unitarily under the Schrödinger equation, there are also ontologically primitive "branches" (or "worlds") which "split". I think this is obviously wrong.
As it is the Many Worlds Interpretation, I think it is reasonable to expect there to be worlds in the resulting ontology.
But if you wish to defend a worldless version of MWI which just contains "a wavefunction evolving unitarily under the Schrödinger equation", feel free to explain how that is compatible with special relativity.
note that the SEP article only says that it's "unclear" how to formulate it in such a way as to be compatible with SR
It's also unclear where the emperor's clothes are.
"Branches" are just patterns that emerge when you zoom out to the macro-scale
Patterns of what? Macro-scale of what?
"If 'something it's like' is interpreted in the informal everyday sense where 'access consciousness' and 'phenomenal consciousness' are not conceived of as separate, then yes absolutely there's something it's like. Moreover, to the extent that the question carries ethical 'weight', again the answer must be yes. But when you try to do fractional distillation, separating out the pure P-consciousness, and ask whether simulated people are P-conscious, then the question loses all of its meaning."
Congratulations, it looks like you're pioneering a whole new stage in the appropriation of names for consciousness by people who claim it doesn't exist. The only reason we have talk about "qualia" is because simpler words like "sensation" have been appropriated to designate material events in the nervous system. One needs to be able to talk about subjective sensation itself - the thing we actually experience - and not just the physical events in the nervous system which are supposed to be its material correlate.
Until now, I have never seen anyone simultaneously deny the existence of phenomenal consciousness (yet another name for subjectivity, i.e. actual consciousness, consciousness as it actually experienced) while affirming that "what it's like to be an X" has some meaning. Until now, that second expression has been still another name for subjectivity, consciousness experienced from the inside. But apparently, not any more. What on earth it does mean, coming from you, I have no idea.
My head just spins trying to understand what's going on in yours. You espouse a physical ontology in which there are no "worlds", or in which the existence of a world is somehow an approximate thing, a matter of opinion or perspective, even though you're in a world. And, you say there are no facts about consciousness - there's no fact about whether a simulated person is conscious or not, there's no fact about whether you're conscious or not. It's just crazy, and yet I assume that awareness of the world's existence and awareness of your own existence does play a role in the functioning of your mind.
So the question is, how can an intelligent and self-aware person adopt a philosophical ideology which explicitly denies the most epistemologically elementary facts there are?
As it is the Many Worlds Interpretation, I think it is reasonable to expect there to be worlds in the resulting ontology.
Allow me to refresh your memory of what I said previously. "Not really. I suspect that what you're referring to as "MWI" contains the idea that, in addition to a wavefunction evolving unitarily under the Schrödinger equation, there are also ontologically primitive "branches" (or "worlds") which "split"."
You ignored one of the words - do you see which one?
...But if you wish to defend a w
Permutation City is an awesome novel that was written in 1994. Even if the author, Greg Egan, used a caricature of this community as a bad guy in a more recent novel, his work is still a major influence on a lot of people around these parts who have read it. It dissolves so many questions around uploading and simulation that it's hard for someone who has read the book to talk about simulationist metaphysics without wanting to reference the novel... but doing that runs into constraints imposed by spoiler etiquette.
So go read Permutation City if you haven't read it already because it's philosophically important and a reasonably fun read.
In the meantime, if you haven't then you should also read A Fire Upon The Deep by Vernor Vinge (of "singularity" coining fame) and then read Eliezer's fan fic The Finale of the Ultimate Meta Mega Crossover which references both of them in interesting ways to make substantive philosophical points and doesn't take too long to read.
In the comments below there will be discussion that has spoilers for all three works.