[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.

If the two theories make the same predictions, what is the point? Why not just stick with the old fuddy duddy one reality?

For example, Lagrangian and Hamiltonian mechanics make the same predictions and are completely equivalent in most cases, but have different uses. There is nothing wrong with picking the formalism more convenient for a specific problem. Granted, MWI does not have a specific formalism, but I allow that it can still provide an inspiration or an intuition in certain problems, which then has to be checked by doing the calculations.

As for the reasons why EY considers the MWI advocacy being important to applied rationality, they are explained in the earlier reruns. Can't say that I agree, but many regulars do, so more power to them.

0wedrifid14y

I don't recall any regulars expressing agreement that MWI advocacy is important to applied rationality to the degree suggested by Eliezer. (It could have happened but it would look odd to me.)

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