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Luke_A_Somers comments on [SEQ RERUN] Where Physics Meets Experience - Less Wrong Discussion

2 Post author: MinibearRex 16 April 2012 04:04AM

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Comment author: Luke_A_Somers 16 April 2012 03:53:25PM 1 point [-]

"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.

Comment author: Tyrrell_McAllister 18 April 2012 08:39:57PM 0 points [-]

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 author: wedrifid 16 April 2012 04:15:51PM -1 points [-]

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.

Comment author: ArisKatsaris 18 April 2012 08:54:48PM *  2 points [-]

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 author: Luke_A_Somers 17 April 2012 04:17:21PM *  1 point [-]

"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.

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