[SEQ RERUN] If Many-Worlds Had Come First

MinibearRex

Today's post, If Many-Worlds Had Come First was originally published on 10 May 2008. A summary (taken from the LW wiki):

If early physicists had never made the mistake, and thought immediately to apply the quantum laws at all levels to produce macroscopic decoherence, then "collapse postulates" would today seem like a completely crackpot theory. In addition to their other problems, like FTL, the collapse postulate would be the only physical law that was informally specified - often in dualistic (mentalistic) terms - because it was the only fundamental law adopted without precise evidence to nail it down. Here, we get a glimpse at that alternate Earth.

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 Collapse Postulates, 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, If Many-Worlds Had Come First was originally published on 10 May 2008. A summary (taken from the LW wiki):

If early physicists had never made the mistake, and thought immediately to apply the quantum laws at all levels to produce macroscopic decoherence, then "collapse postulates" would today seem like a completely crackpot theory. In addition to their other problems, like FTL, the collapse postulate would be the only physical law that was informally specified - often in dualistic (mentalistic) terms - because it was the only fundamental law adopted without precise evidence to nail it down. Here, we get a glimpse at that alternate Earth.

As a rule, how it works is that non-physicist MWI believers just assume that configurations are the preferred basis, because spatial configurations are the everyday reality they're already familiar with, and physicist MWI believers import whatever they need from Copenhagen QM in order to avoid having an ontologically preferred basis, even though a self-sufficient objective theory should have no logical room for such "imported" extra components.

How, do you think, does EY think about it? I could not find it stated clearly anywhere in the sequence, beyond "MWI is decoherence, decoherence is MWI", which is not overly helpful.

Along with the emphasis on decoherence, he has expressed a liking for Robin Hanson's "mangled worlds" approach, for the position basis because of the importance of relativistic locality, and for the "time capsules" of Julian Barbour. These ideas are at odds with each other in various ways. The last two utilize the position basis, the first two do not; and Barbour's time-capsules are universe-wide configurations, so the spirit of relativity is lacking in his theory, putting it at odds with the other motivation for preferring the position... (read more)