Scott Aaronson's cautious optimism for the MWI

calef

http://www.scottaaronson.com/blog/?p=1103

Eliezer's gung-ho attitude about the realism of the Many Worlds Interpretation always rubbed me the wrong way, especially in the podcast between both him and Scott (around 8:43 in http://bloggingheads.tv/videos/2220). I've seen a similar sentiment expressed before about the MWI sequences. And I say that still believing it to be the most seemingly correct of the available interpretations.

I feel Scott's post does an excellent job grounding it as a possibly correct, and in-principle falsifiable interpretation.

http://www.scottaaronson.com/blog/?p=1103

I feel Scott's post does an excellent job grounding it as a possibly correct, and in-principle falsifiable interpretation.

You say that there are multiple copies of me inside the wavefunction

I do? Well, I can pretend I do, at least.

Is that because there is one of me that splits into many, or were there just parallel mes living separate but similar lives?"

If we want to recover classical choices in cases where there are clear classical analogs, one of you splits into one. If you'd rather follow other intuitions, though, you'll get different answers (see: quantum suicide).

Note that since humans aren't energy eigenstates, there is no general way to get completely "parallel lives" - you always interfere. But because the world is nice and orderly you can get pretty dang close to parallel most of the time.

So far you've used the example "| / > = | | > + | >", which doesn't tell anyone whether they should think of themselves as "/", as "|" and " ", or otherwise answer the question.

Well, it answers the person who asks "But is the line really one component, or is it really two components?" And that answer is that they've gotten their levels confused - number of components is in your description of the line, not in the line.

Which, to make sure I'm being clear, is analogous to how I interpreted Quantumental's sentence "Obviously both overlap and non-overlap cannot be true, they are ontologically different." If we go with a correspondence theory of truth, we run into a problem because there is no overlap or non-overlap out in quantum mechanics that this sentence could correspond to. Instead, the thing that would make it true or false is humans; specifically how they choose what's right when presented with quantum mechanics. Unfortunately, humans are inconsistent, so you immediately run into the problem of how to idealize them.

I get it now. You're saying that the relativism of how one may define one's personal identity is so great that, in a quantum multiverse, even whether you are splitting into multiple selves or not is a matter of how you define yourself.

Still, that's not the end of it, because then we can ask exactly what parts of the wavefunction are "potential person-parts". I may have some freedom to choose whether a particular object, trait, thought, or state of mind that once existed or that could exist is "part of me", but at some level there has t... (read more)