[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.

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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.

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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 you're thinking of building any strange philosophies around many-worlds, you probably shouldn't - that's not what it's for.

This includes any discussion of quantum immortality/suicide and MWI-based arguments for decision theories, anthropic biases etc. If you can construct a certain line of reasoning about observed world using MWI, you should be able to do the same if you assume that only this single world "exists". Granted, it might not be as obvious, but it must be doable.

There is nothing wrong with using MWI for inspiration, there is everything wrong with saying that some argument is true "because MWI!".

If you can construct a certain line of reasoning about observed world using MWI, you should be able to do the same if you assume that only this single world "exists".

If the two theories make the same predictions, what is the point? Why not just stick with the old fuddy duddy one reality? Is MWI just a fashion statement? Just a theory that falls under Quine's "inscrutability of translation"?

Note that a hidden variable theory does make a prediction - that there are hidden variables we may one day discover and use to make better predict... (read more)

4wedrifid14y

This seems false. There is no particular reason that all things must be reducible to a single world map without loss.

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