Reading Yudkowsky, part 40

by Luke Muehlhauser on May 27, 2011 in Eliezer Yudkowsky,Resources,Reviews

AI researcher Eliezer Yudkowsky is something of an expert at human rationality, and at teaching it to others. His hundreds of posts at Less Wrong are a treasure trove for those who want to improve their own rationality. As such, I’m reading all of them, chronologically.

I suspect some of my readers want to “level up” their rationality, too. So I’m keeping a diary of my Yudkowsky reading. Feel free to follow along.

His 314th post is Quantum Explanations:

I think I must now temporarily digress from the sequence on zombies (which was a digression from the discussion of reductionism, which was a digression from the Mind Projection Fallacy) in order to discuss quantum mechanics.  The reasons why this belongs in the middle of a discussion on zombies in the middle of a discussion of reductionism in the middle of a discussion of the Mind Projection Fallacy, will become apparent eventually.

I am not a physicist, and physicists famously hate it when non-professional-physicists talk about QM.  But I do have some experience with explaining mathy things that are allegedly “hard to understand”.

Besides, as a Bayesian, I don’t believe in phenomena that are inherently confusing.  Confusion exists in our models of the world, not in the world itself.  If a subject is widely known as confusing, not just difficult… you shouldn’t leave it at that.  It doesn’t satisfice; it is not an okay place to be.  Maybe you can fix the problem, maybe you can’t; but you shouldn’t be happy to leave students confused.

I very much like Yudkowsky’s approach:

I am not going to tell you that quantum mechanics is weird, bizarre, confusing, or alien. QM is counterintuitive, but that is a problem with your intuitions, not a problem with quantum mechanics.  Quantum mechanics has been around for billions of years before the Sun coalesced from interstellar hydrogen.  Quantum mechanics was here before you were, and if you have a problem with that, you are the one who needs to change.  QM sure won’t.  There are no surprising facts, only models that are surprised by facts; and if a model is surprised by the facts, it is no credit to that model.

It is always best to think of reality as perfectly normal.  Since the beginning, not one unusual thing has ever happened.

The goal is to become completely at home in a quantum universe.  Like a native.  Because, in fact, that is where you live.

In the coming sequence on quantum mechanics, I am going to consistently speak as if quantum mechanics isperfectly normal; and when human intuitions depart from quantum mechanics, I am going to make fun of theintuitions for being weird and unusual.  This may seem odd, but the point is to swing your mind around to a nativequantum point of view.

Also, Eliezer won’t do the usual historical-introduction thing:

Dragging a modern-day student through all [the historical theoretical back-and-forth] may be a historically realistic approach to the subject matter, but it also ensures the historically realistic outcome of total bewilderment. Talking to aspiring young physicists about “wave/particle duality” is like starting chemistry students on the Four Elements.

An electron is not a billiard ball, and it’s not a crest and trough moving through a pool of water.  An electron is a mathematically different sort of entity, all the time and under all circumstances, and it has to be accepted on its own terms.

If you try to think of an electron as being like a billiard ball on some days, and like an ocean wave on other days, you will confuse the living daylights out of yourself.

Third, he won’t start with experimental results. Instead, he’ll start by explaining how things fundamentally work:

Maybe the monomaniacal focus on experimental observations made sense in the dark decades when no oneunderstood what was fundamentally going on, and you couldn’t start there, and all your models were just mysterious maths that gave good experimental predictions… you can still find this view of quantum physics presented in many books… but maybe today it’s worth trying a different angle?  The result of the standard approach is standard confusion.

…I think it is worth trying to teach from the perspective of the quantum world first, and talking about classical experimental results afterward.

I am not going to start with the normal classical world and then talk about a bizarre quantum backdrop hidden behind the scenes.  The quantum world is the scene and it defines normality.

And finally:

I am going to take a strictly realist perspective on quantum mechanics – the quantum world is really out there, our equations describe the territory and not our maps of it, and the classical world only exists implicitly within the quantum one.  I am not going to discuss non-realist views in the early stages of my introduction, except to say why you should not be confused by certain intuitions that non-realists draw upon for support.  I am not going to apologize for this, and I would like to ask any non-realists on the subject of quantum mechanics to wait and hold their comments until called for in a later post.  Do me this favor, please.  I think non-realism is one of the main things that confuses prospective students, and prevents them from being able to concretely visualize quantum phenomena.  I will discuss the issues explicitly in a future post.

To sum up, my goal will be to teach you to think like a native of a quantum universe, not a reluctant tourist.

Embrace reality.  Hug it tight.

Okay great! The explanations begin in Configurations and Amplitude:

So the universe isn’t made of little billiard balls, and it isn’t made of crests and troughs in a pool of aether…  Then what is the stuff that stuff is made of?

Unfortunately, there is no way I can usefully summarize the series on quantum mechanics, so you’ll have to read it for yourself. The next several posts in the series are:

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{ 1 comment… read it below or add one }

Reginald Selkirk May 27, 2011 at 12:48 pm

Quantum mechanics was here before you were, and if you have a problem with that, you are the one who needs to change.

Robert Lanza, M.D. needs to change


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