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Brigid comments on Welcome to Less Wrong! (2012) - Less Wrong

25 Post author: orthonormal 26 December 2011 10:57PM

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Comment author: Brigid 01 May 2012 11:01:39PM 14 points [-]

Hi, I’m Brigid. I’ve been reading through the Sequences for a few weeks now, and am just about to start the Quantum Section (about which I am very excited). I found out about this site from an email the SIAI sent out. I’m an Signals Intelligence officer in the Marine Corps and am slated to get out of the military in a few months. I’m not too sure what I am going to do yet though; as gung-ho as I originally was about intel, I’m not sure I want to stay in that specific field. I was a physics and political science major in college, with a minor in women’s studies. I’ve been interested in rationality for a few years now and have thoroughly enjoyed everything I’ve read so far here (including HPMOR) . Also, if there is anyone who is interested in starting a Meetup group in Hawaii (Oahu) let me know!

Comment author: Eliezer_Yudkowsky 02 May 2012 06:07:45AM 3 points [-]

Hi, Brigid! Pleased to have you here! Experience has shown that by far the best way to find out if anyone's interested in starting an LW group is to pick a meeting place, announce a meetup time, and see if anyone shows up - worst-case scenario, you're reading by yourself in a coffeeshop for an hour, and this is not actually all that bad.

Comment author: shminux 01 May 2012 11:14:57PM *  3 points [-]

Welcome!

am just about to start the Quantum Section (about which I am very excited).

A warning: while the QM sequence in general is very readable and quite useful for the uninitiated, the many-worlds advocacy is best taken with a mountain of salt. Consider skipping the sequence on the first pass, and returning to it later, after you've covered everything else. It is fairly stand-alone and is not relevant to rationality in general.

Comment author: fubarobfusco 02 May 2012 01:15:49AM *  3 points [-]

Well, there are a couple of things going on in the QM sequence. One of them is MWI. The other is the general debunking of the commonly-held idea that QM is soooooooo weeeeeeeeird.

Comment author: shminux 02 May 2012 02:00:39AM 1 point [-]

Yes, that's the good part.

Comment author: Eliezer_Yudkowsky 02 May 2012 06:11:27AM 3 points [-]

A meta-warning: Take shminux's "mountain of salt" advice with an equally large mountain of salt plus one more grain - as will become starkly apparent, there's a reason why the current QM section is written the way it is, it's not meant to be skipped, and it's highly relevant to rationality in general.

Comment author: RichardKennaway 02 May 2012 06:38:24AM 12 points [-]

How would the Sequences be different, other than in the QM parts, if we lived in a classical universe, or if we had not yet discovered QM?

Comment author: [deleted] 02 May 2012 07:22:38AM 2 points [-]

Wild Mass Guessing: in a classical universe, particles are definable individuals. This breaks a whole mess of things; a perfect clone of you is no longer you, and etc.

Comment author: JGWeissman 02 May 2012 05:21:26PM 9 points [-]

a perfect clone of you is no longer you

The lack of identity of individual particles is knock down argument against our identities being based on the identities of individual particles. However, if there was identity of individual particals, this does not require that the identity of individual particles contribute to our identities, it would just remove a knock down argument against that idea.

Comment author: DanArmak 02 May 2012 05:45:30PM *  1 point [-]

(Almost) all the particles in our bodies are replaced anyway, on the scale of a few years. Replacement here means a period of time when you're without the molecule, and then another comes in to take its place; so it's real whether or not particles have identities. This applies to quite large things like molecules. Once we know that, personal identity rooted in specific particles is shaky anyway.

Comment author: thomblake 02 May 2012 05:29:19PM *  1 point [-]

An important point.

Heraclitus probably didn't believe in lack of identity of individual particles, but he did believe we are patterns of information, not particular stuff.

EDIT: On second thought, he'd probably work out lack of identity of individual particles if pressed, following from that.

Comment author: RichardKennaway 02 May 2012 07:54:31AM 3 points [-]

That minds are physical processes seems discoverable without knowing why matter is made of atoms and what atoms are made of. That elimination of mentalism seems sufficient to justify the ideas of uploading, destructive cryonics, artificial people, and so on.

But I'm actually more interested in what implications there are, if any, for practical rationality here and now. (I will be unmoved by the answer "But FAI is the most practical thing to work on, we'll all die if it's done wrong!!!")

Comment author: DanArmak 02 May 2012 05:50:04PM 4 points [-]

a perfect clone of you is no longer you

Not necessarily. "What/who is you" is a matter of definition to a large extent. If particles have identities (but are still identical to all possible measurements), that doesn't stop me from defining my personhood as rooted in the pattern, and identifying with other sufficiently similar instances of the pattern.

Comment author: thomblake 02 May 2012 03:41:47PM 6 points [-]

it's not meant to be skipped, and it's highly relevant to rationality in general.

A few people have asserted this, but how is it actually relevant? Is it just a case study, or is there something else there? As RichardKennaway asks, how does QM make a difference to rationality itself?

Comment author: ArisKatsaris 02 May 2012 04:18:14PM *  2 points [-]

Speaking from a non-physicist perspective, much of what the QM sequence helped teach me is helping see the world from bottom-up; QM is regular, but it adds up to normality, and it's normality that's weird. Delving down into QM is going up the rabbit's hole away from weirdness and normality, and into mathematical regularity.

By analogy, normal people are similarly weird because they're the normality that was produced as the sum of a million years of evolution. Which in turn helps you realize that a random mind plucked out of mindspace is unlikely to have the characteristics we attribute to humanlike normality. Because normality is weird.

Once you go from bottom-to-top, you also help dissolve some questions like problems of identity and free will (though I had personally dissolved the supposed contradiction between free will and determinism many years before I encountered LessWrong) -- I still think that many knots people tie themselves over regarding issues like Quantum Suicide or Doomsday Dilemmas, are caused by insufficient application of the bottoms-up principle, or worse yet a half-hearted application thereof.

Comment author: DanArmak 02 May 2012 04:38:44PM *  2 points [-]

Because normality is weird.

It's bad enough that we've got people talking about things not being weird, as if weirdness is an objective property rather than something in the mind of the observer. Your words which I quoted are even worse; they're a self-contradiction.

If you're not willing to let the word "weird" have its dictionary definition, please, please just taboo it and let the subject die, rather than trying to redefine it as the opposite of the original meaning.

Comment author: chaosmosis 02 May 2012 04:42:37PM 2 points [-]

The commenter was saying "our intuitive understanding of reality" is weird, I think. That's why the commenter was able to noncontradictorily say that Quantum Mechanics fixed some problems and made things less weird.

Comment author: DanArmak 02 May 2012 05:09:03PM 0 points [-]

"our intuitive understanding of reality" is weird

Let's unpack what that means, because I feel we might be disagreeing over the meaning of the word. I'll use Wiktionary but if you don't like the definitions given feel free to substitute.

Weird (when used as adjective): 1. Strange. 2. Deviating from the normal, bizarre. (And some unrelated meanings.)

"Strange" in turn unpacks to: 1a. Not normal; odd, unusual, surprising, out of the ordinary. 1b. Unfamiliar, not yet part of one's experience. (Ex: a strange town.)

For completeness I looked up normal. I believe the only relevant meaning is "usual; ordinary".

Summing up, I define "weird" as meaning "not normal; irregular, exceptional; unexpected". And a secondary meaning of "strange, unfamiliar".

In light of this, what does it mean to say that:

"our intuitive understanding of reality" is weird

Is our intuitive understanding not "normal", exceptional, or unexpected? It's certainly normal among humans; and we have no concrete examples of a larger reference class of conscious beings. It's been argued that other life-forms would form different intuitions, but at least all Earth life except maybe microbes operates on classical-mechanics intuitions. Arguing that this isn't "normal" requires more than just saying something different is possible in principle.

As for the secondary meaning, quantum mechanics (and relativity for that matter) certainly describes behavior which is strange and unfamiliar to our intuitions. But then the correct use of the word "weird" is precisely to say that QM is weird. Not that we are.

Comment author: chaosmosis 02 May 2012 06:56:43PM *  1 point [-]

I don't think those definitions really capture some of the relevant connotations that weirdness has related to accuracy and consistency. I personally didn't even realize the exact problem you had with the commenter because the way zhe used "weird" made perfect sense to me.

I also don't like prescriptivist theories of grammar very much and think that the original comment was clearly understandable and was perhaps less clearly intended to subvert the common belief that "QM is weird", which is a belief that has been criticized in multiple places on this website, and I appreciated the creative attempt to get rid of the flawed belief by reframing "normalcy".

My initial overview of these comments made me believe there was a lack of communication, now I see the initial hints I missed that show that you're upset because words like "weird" are used informally. My bad for the initial comment, then.

Comment author: DanArmak 02 May 2012 07:04:37PM 3 points [-]

I also don't like prescriptivist theories of grammar very much

Me neither. I'm bringing up dictionary definitions as descriptions, not as prescriptions. I happen to agree with the dictionary (and it's not my native language anyway), and since you seem to use a different meaning/definition, please tell me what it is!

and think that the original comment was clearly understandable

I, at least, apparently still don't understand it.

Or rather, I understand the intent (because it's been explained) but can't understand how that intent can be read from the original words.

Comment author: ArisKatsaris 02 May 2012 04:52:16PM *  0 points [-]

My whole point was about being helped to gain an additional perspective; seeing something from bottoms up.

When you say that weirdness is "in the mind of the observer", you're quite obviously correct in the most plain sense, but you seem to be assuming that a mind can have only one point of view, and not intentionally attempt or even manage to shift between different point of views.

Comment author: DanArmak 02 May 2012 05:34:17PM 0 points [-]

I understand your point about the POVs. In light of that, here's what bothers me about saying "normality is weird".

If we look at a quantum-mechanical system from the classical POV, we notice that no classical laws (even classical-style laws we don't know yet) can explain its behavior. So it looks weird to us. That's fine.

If we look at a classical system from the quantum POV, we can't calculate its behavior on the quantum level, it's too complex. But if we could - and in principle the laws of physics tell us how to do it - then we expect to predict its behavior correctly. So why should it seem weird?

The two situations aren't symmetrical. We used to believe in classical mechanics, and then we discovered quantum phenomena, and we saw that they were weird. This was because the laws of physics we used were wrong! Now that we use the right ones (hopefully), nothing should look weird anymore, including "classical" systems.

It's true that QM is at best incomplete, and we can't yet use it correctly in some relativistic situations. So those situations still look weird from a QM POV. But this doesn't apply to our normal lives.

Comment author: thomblake 02 May 2012 04:22:58PM 1 point [-]

Yeah, that's roughly the best I could come up with, but it doesn't seem sufficient. Noticing the extent of cognitive bias is enough to figure out that humans are weird.

Comment author: shminux 02 May 2012 04:52:07PM 0 points [-]

I'm curious how you used this approach to resolve the Quantum Suicide argument.

Comment author: ArisKatsaris 02 May 2012 05:06:02PM *  0 points [-]

I should perhaps make a fuller post about this at some point, but in brief: "Individuals" are in reality quite divisible (pun intended). Quantum Suicide makes sense to me only if you have a top-down pespective on identity that either persists as a whole or is destroyed as a whole and nothing in between.

If you instead view the self as some bizarre arbitrary conglameration of qualia-producing processes (including whatever processes produce self-awareness, however they do it), then the very concept of destruction or persistence must be applied to actually individual thought-processes, and is meaningless when applied to whole people.

Comment author: DanArmak 02 May 2012 05:35:39PM 0 points [-]

If you instead view the self as some bizarre arbitrary conglameration

Again with the bizarre :-)

Comment author: shminux 03 May 2012 04:27:52PM *  1 point [-]

I have dutifully gone through the entire sequence again, enjoying some cute stories along the way, and my best guess of what EY means is that it is relevant not in any direct sense ("QM is what rationality is built on"), but more as a teaching tool: it brings "traditional Science" in conflict with "Bayesian rationality". (The Bayesianism wins, of course!) The MWI also lends some support to the EY's preferred model, Barbour's timeless physics, and thus inspires the TDT.

Comment author: thomblake 03 May 2012 04:41:33PM 2 points [-]

That still doesn't seem like enough to justify the reversal from "not relevant" to "highly relevant".

Comment author: shminux 03 May 2012 06:23:49PM 1 point [-]

What reversal? I still think that it detracts from the overall presentation of "modern rationality" by getting people sidetracked into learning open problems in physics at a pop-sci level. Whatever points EY was trying to make there can surely be made better without it.

Comment author: thomblake 03 May 2012 06:30:18PM 1 point [-]

What reversal?

I meant where you said "not relevant" and Eliezer responded with "highly relevant". It sounds to me as though he thinks it's fundamental to rationality or something. Very confusing.

Comment author: thomblake 03 May 2012 07:34:20PM 0 points [-]

It looks like Eliezer answers my question in this post.

Comment author: shminux 03 May 2012 07:59:39PM *  1 point [-]

Have you noticed any confusion?

It just seems almost too good to be true that I now get what plenty of genius quantum physicists still can't.

Hmm, "too good to be true"... Does this suggest anything?

In physics, you can get absolutely clear-cut issues. Not in the sense that the issues are trivial to explain. But if you try to apply Bayes to healthcare, or economics, you may not be able to formally lay out what is the simplest hypothesis, or what the evidence supports.

So why bother with an example where Bayes works the worst and is most confusing? [EDIT: What I mean is that the scientific principle works so much better in physics compared to other fields mentioned, Bayes clearly is not essential there]

Bayes-Goggles on: The simplest quantum equations that cover all known evidence don't have a special exception for human-sized masses. There isn't even any reason to ask that particular question. Next!

This is an actual testable prediction. Suppose such an exception is found experimentally (for example, self-decoherence due to gravitational time dilation, as proposed by Penrose, limiting the quantum effects to a few micrograms or so). Would you expect EY to retract his Bayesian-simplest model in this case, or "adjust" it to match the new data? Honestly, what do you think is likely to happen?

Okay, Bayes-Goggles back on. Are you really going to believe that large parts of the wavefunction disappear when you can no longer see them? As a result of the only non-linear non-unitary non-differentiable non-CPT-symmetric acausal faster-than-light informally-specified phenomenon in all of physics? Just because, by sheer historical contingency, the stupid version of the theory was proposed first?

Have you noticed that this is a straw-Copenhagen, and not the real thing?

Comment author: dlthomas 03 May 2012 08:42:37PM 6 points [-]

This is an actual testable prediction. Suppose such an exception is found experimentally (for example, self-decoherence due to gravitational time dilation, as proposed by Penrose, limiting the quantum effects to a few micrograms or so). Would you expect EY to retract his Bayesian-simplest model in this case, or "adjust" it to match the new data? Honestly, what do you think is likely to happen?

Honestly, when the first experiment shows that we don't see quantum effects at some larger scale when it is otherwise believed that they should show up, I expect EY to weaken, but not reverse, his view that MWI is probably correct - expecting that there is an error in the experiment. When it has been repeated, and variations have shown similar results, I expect him to drop MWI, because it now longer explains the data. I don't have a specific prediction regarding just how many experiments it would take; this probably depends on several factors, including the nature and details of the experiments themselves.

This is from my personal model of EY, who seems relatively willing to say "Oops!" provided he has some convincing evidence he can point to; this model is derived solely from what I've read here, and so I don't ascribe it hugely high confidence, but that's my best guess.