[SEQ RERUN] Where Physics Meets Experience
post by MinibearRex · 2012-04-16T04:04:16.542Z · LW · GW · Legacy · 19 commentsToday's post, Where Physics Meets Experience was originally published on 25 April 2008. A summary (taken from the LW wiki):
Meet the Ebborians, who reproduce by fission. The Ebborian brain is like a thick sheet of paper that splits down its thickness. They frequently experience dividing into two minds, and can talk to their other selves. It seems that their unified theory of physics is almost finished, and can answer every question, when one Ebborian asks: When exactly does one Ebborian become two people?
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 Which Basis Is More Fundamental?, and you can use the sequence_reruns tag or rss feed to follow the rest of the series.
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19 comments
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comment by Tyrrell_McAllister · 2012-04-18T20:25:12.754Z · LW(p) · GW(p)
So, I get that De'da = Daniel Dennett and Yu'el = Eliezer Yudkowsky. But who is the real-world analogue of Po'mi? ETA: I guess it's Mitchell Porter.
Replies from: Oscar_Cunningham, ESRogs, shminux↑ comment by Oscar_Cunningham · 2012-04-19T17:01:57.535Z · LW(p) · GW(p)
De'da may also be David Deutsch. Perhaps the two of them only recently split from each other...
Replies from: Tyrrell_McAllister↑ comment by Tyrrell_McAllister · 2012-04-19T17:07:22.292Z · LW(p) · GW(p)
In the comment thread to the next post, Eliezer says that Daniel Dennett was the intended interpretation, though he acknowledges that David Deutsch might also make sense after someone else suggests it.
↑ comment by ESRogs · 2013-04-18T08:12:58.887Z · LW(p) · GW(p)
I was guessing Michael Polanyi, but now I think you're right.
↑ comment by shminux · 2012-04-18T20:37:07.435Z · LW(p) · GW(p)
Clever!
Replies from: Tyrrell_McAllister↑ comment by Tyrrell_McAllister · 2012-04-18T21:05:20.413Z · LW(p) · GW(p)
Mike Blume beat me to it, and figured out who Bo'ma is, too.
comment by Bugmaster · 2012-04-16T09:29:53.326Z · LW(p) · GW(p)
Minor nitpick:
We don't know what makes sharkras bloom only in spring... You may not know why sharkras bloom in the summer...
Ok, so when do those things actually bloom ? Spring, summer, or both ? Or did the Ebborian world split down the middle while they were talking ?
Replies from: Tyrrell_McAllister↑ comment by Tyrrell_McAllister · 2012-04-18T20:18:44.498Z · LW(p) · GW(p)
Ebborian's are said to forget facts easily because of the two-dimensional architecture of their brains. This is usually not such a problem because they are better at re-deriving facts from more-fundamental principles. But they don't know how to derive the blooming time of sharkras, so it's no surprise that Yu'el has a hard time remembering when it happens. /fanwank.
comment by Luke_A_Somers · 2012-04-16T15:53:25.765Z · LW(p) · GW(p)
"Now," says Po'mi, "if fundamental physics has nothing to do with consciousness, can you tell me why the subjective >probability of finding ourselves in a side of the split world, should be exactly proportional to the square of the thickness of >that side?"
There is a great terrible silence.
"WHAT?" says Yu'el.
"WHAT?" says De'da.
"WHAT?" says Nharglane.
"WHAT?" says the entire audience of Ebborians.
"WHAT?"
That's not how it works in QM. It comes out as squared amplitudes because they're orthogonal. If you had them in one dimension as described, it would be linear.
Replies from: Tyrrell_McAllister, wedrifid↑ comment by Tyrrell_McAllister · 2012-04-18T20:39:57.455Z · LW(p) · GW(p)
That's not how it works in QM. It comes out as squared amplitudes because they're orthogonal.
Isn't that just a tautological consequence of how orthogonality is defined in Hilbert space? One way to develop quantum mechanics is to start with the pure states for some observable, which is all that you ever "actually experience", and then define an inner product on Hilbert space such that these states are orthonormal.
↑ comment by wedrifid · 2012-04-16T16:15:51.293Z · LW(p) · GW(p)
That's not how it works in QM. It comes out as squared amplitudes because they're orthogonal. If you had them in one dimension as described, it would be linear.
You need to read the immediate context of your quote. The previous 5 paragraphs to be precise. The quote in question is not talking about the one dimensional splitting. They have discovered actual quantum mechanics now and are talking about how much easier it is for them to understand because they at least understand splitting already.
Replies from: ArisKatsaris, Luke_A_Somers↑ comment by ArisKatsaris · 2012-04-18T20:54:48.490Z · LW(p) · GW(p)
It's not quantum mechanics, it's just an analogy.
In the followup chapter, you e.g. get the following hypothetical:
"Why not just let the 'degree of existence' be a complex number, while you're at it?"
Bo'ma rolls his eyes. "Please stop mocking me. I can't even imagine any possible experimental evidence which would point in the direction of that conclusion. You'd need a case where two events that were real in opposite directions canceled each other out."
Which hypothetical is actually a reference to an element of real QM -- as the amplitudes of configurations are indeed complex numbers, and can indeed cancel each other other. (if I'm not mistaken)
↑ comment by Luke_A_Somers · 2012-04-17T16:17:21.693Z · LW(p) · GW(p)
"And we also discovered," continues Po'mi, "that our very planet of Ebbore, including all the people on it, has a four-dimensional thickness, and is constantly fissioning along that thickness, just as our brains do.
This is very different from our quantum mechanics, in precisely the fashion described. I stand by my claim that they would experience linear dependence.
comment by gjm · 2012-04-16T10:51:07.291Z · LW(p) · GW(p)
It ends "To be continued" but I don't think it ever was...
Replies from: Nonecomment by [deleted] · 2012-04-16T08:24:50.536Z · LW(p) · GW(p)
I've never understood the arguments laid out in this dialog, probably because they are embedded in this alien culture and/or biology. What's the main point of this post?
Replies from: MinibearRex↑ comment by MinibearRex · 2012-04-17T03:50:21.145Z · LW(p) · GW(p)
This post doesn't really have a "main point" per se. It does, however have a purpose: to set up the point that was made in the next post