[SEQ RERUN] Living in Many Worlds

MinibearRex

Today's post, Living in Many Worlds was originally published on 05 June 2008. A summary (taken from the LW wiki):

The many worlds of quantum mechanics are not some strange, alien universe into which you have been thrust. They are where you have always lived. Egan's Law: "It all adds up to normality." Then why care about quantum physics at all? Because there's still the question of what adds up to normality, and the answer to this question turns out to be, "Quantum physics." If you're thinking of building any strange philosophies around many-worlds, you probably shouldn't - that's not what it's for.

Discuss the post here (rather than in the comments to the original post).

This post is part of the Rerunning the Sequences series, where we'll be going through Eliezer Yudkowsky's old posts in order so that people who are interested can (re-)read and discuss them. The previous post was Why Quantum?, and you can use the sequence_reruns tag or rss feed to follow the rest of the series.

Sequence reruns are a community-driven effort. You can participate by re-reading the sequence post, discussing it here, posting the next day's sequence reruns post, or summarizing forthcoming articles on the wiki. Go here for more details, or to have meta discussions about the Rerunning the Sequences series.

Today's post, Living in Many Worlds was originally published on 05 June 2008. A summary (taken from the LW wiki):

The many worlds of quantum mechanics are not some strange, alien universe into which you have been thrust. They are where you have always lived. Egan's Law: "It all adds up to normality." Then why care about quantum physics at all? Because there's still the question of what adds up to normality, and the answer to this question turns out to be, "Quantum physics." If you're thinking of building any strange philosophies around many-worlds, you probably shouldn't - that's not what it's for.

My instinct is to not kill the loved one, but on virtue-ethics grounds, not because of any sort of counterfactual reciprocity argument. My understanding is that UDT is not actually computable. As a result, no possible agent can act as you describe. So this doesn't seem like a particularly compelling thought experiment.

if I'm deciding what to do with a hostage, it makes no difference what the other party decides. What matters is my judgement of them right before we became causally separated -- and I am skeptical that my decision-making after the separation is useful evidence on this point.

More broadly, I can think of lots of reasons to take counterfactual possibilities into account. But none of them require me to say that the counterfactual "really exists". For instance, I'm worried about people judging me for being reckless, dishonorable, etc. What's the case where I actually care about non-causal interactions?

My understanding is that UDT is not actually computable. As a result, no possible agent can act as you describe. So this doesn't seem like a particularly compelling thought experiment.

Are you confusing UDT with AIXI? It is certainly possible for an agent to act as described and the tricky part isn't anything to do with "UDT" (but rather the possible but difficult task of making the predictions.)

What's the case where I actually care about non-causal interactions?

The case given is sufficient. Anyone who is capable of one-boxing on Newcomb's ... (read more)

6

[SEQ RERUN] Living in Many Worlds

6

6

6

[SEQ RERUN] Living in Many Worlds

6

6