trentmkelly/LessWrong-43k huggingface dataset:
Quantum Explanations
by Eliezer Yudkowsky — 2008-04-09T08:15:33.000Z

There’s a widespread belief that quantum mechanics is supposed to be confusing. This is not a good frame of mind for either a teacher or a student.

And I find that legendarily “confusing” subjects often are not really all that complicated as math, particularly if you just want a very basic—but still mathematical—grasp on what goes on down there.

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

I wrote the Intuitive Explanation of Bayesian Reasoning because people were complaining that Bayes’s Theorem was “counterintuitive”—in fact it was famously counterintuitive—and this did not seem right. The equation just did not seem complicated enough to deserve the fearsome reputation it had. So I tried explaining it my way, and I did not manage to reach my original target of elementary school students, but I get frequent grateful emails from formerly confused folks ranging from reporters to outside academic college professors.

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.

The first way in which my introduction is going to depart from the traditional, standard introduction to quantum mechanics, is that I am not going to tell you that quantum mechanics is supposed to be confusing.

I am not going to tell you that it’s okay for you to not understand quantum mechanics, because no one understands quantum mechanics, as Richard Feynman once claimed. There was a historical time when this was true, but we no longer live in that era.

I am not going to tell you: “You don’t understand quantum mechanics, you just get used to it.” (As von Neumann is reputed to have said; back in the dark decades when, in fact, no one did understand quantum mechanics.)

Explanations are supposed to make you less confused. If you feel like you don’t understand something, this indicates a problem—either with you, or your teacher—but at any rate a problem; and you should move to resolve...
Belief in the Implied Invisible
by Eliezer Yudkowsky — 2008-04-08T07:40:49.000Z

One generalized lesson not to learn from the Anti-Zombie Argument is, "Anything you can't see doesn't exist."

It's tempting to conclude the general rule. It would make the Anti-Zombie Argument much simpler, on future occasions, if we could take this as a premise. But unfortunately that's just not Bayesian.

Suppose I transmit a photon out toward infinity, not aimed at any stars, or any galaxies, pointing it toward one of the great voids between superclusters. Based on standard physics, in other words, I don't expect this photon to intercept anything on its way out. The photon is moving at light speed, so I can't chase after it and capture it again.

If the expansion of the universe is accelerating, as current cosmology holds, there will come a future point where I don't expect to be able to interact with the photon even in principle—a future time beyond which I don't expect the photon's future light cone to intercept my world-line. Even if an alien species captured the photon and rushed back to tell us, they couldn't travel fast enough to make up for the accelerating expansion of the universe.

Should I believe that, in the moment where I can no longer interact with it even in principle, the photon disappears?

No.

It would violate Conservation of Energy. And the second law of thermodynamics. And just about every other law of physics. And probably the Three Laws of Robotics. It would imply the photon knows I care about it and knows exactly when to disappear.

It's a silly idea.

But if you can believe in the continued existence of photons that have become experimentally undetectable to you, why doesn't this imply a general license to believe in the invisible?

(If you want to think about this question on your own, do so before the jump...)

Though I failed to Google a source, I remember reading that when it was first proposed that the Milky Way was our galaxy —that the hazy river of light in the night sky was made up of millions (or even billions) of stars—that Occam's Razor was invoked against the new hypothesis. Because, you see, the hypothesis vastly multiplied the number of "entities" in the believed universe. Or maybe it was the suggestion that "nebulae"—those hazy patches seen through a telescope—might be galaxies full of stars, that got the invocation of Occam's Razor.

Lex pa...
GAZP vs. GLUT
by Eliezer Yudkowsky — 2008-04-07T01:51:56.000Z

In "The Unimagined Preposterousness of Zombies", Daniel Dennett says:

To date, several philosophers have told me that they plan to accept my challenge to offer a non-question-begging defense of zombies, but the only one I have seen so far involves postulating a "logically possible" but fantastic being — a descendent of Ned Block's Giant Lookup Table fantasy...

A Giant Lookup Table, in programmer's parlance, is when you implement a function as a giant table of inputs and outputs, usually to save on runtime computation. If my program needs to know the multiplicative product of two inputs between 1 and 100, I can write a multiplication algorithm that computes each time the function is called, or I can precompute a Giant Lookup Table with 10,000 entries and two indices. There are times when you do want to do this, though not for multiplication—times when you're going to reuse the function a lot and it doesn't have many possible inputs; or when clock cycles are cheap while you're initializing, but very expensive while executing.

Giant Lookup Tables get very large, very fast. A GLUT of all possible twenty-ply conversations with ten words per remark, using only 850-word Basic English, would require 7.6 * 10585 entries.

Replacing a human brain with a Giant Lookup Table of all possible sense inputs and motor outputs (relative to some fine-grained digitization scheme) would require an unreasonably large amount of memory storage. But "in principle", as philosophers are fond of saying, it could be done.

The GLUT is not a zombie in the classic sense, because it is microphysically dissimilar to a human. (In fact, a GLUT can't really run on the same physics as a human; it's too large to fit in our universe. For philosophical purposes, we shall ignore this and suppose a supply of unlimited memory storage.)

But is the GLUT a zombie at all? That is, does it behave exactly like a human without being conscious?

The GLUT-ed body's tongue talks about consciousness. Its fingers write philosophy papers. In every way, so long as you don't peer inside the skull, the GLUT seems just like a human... which certainly seems like a valid example of a zombie: it behaves just like a human, but there's no one home.

Unless the GLUT is conscious, in which case it wouldn't be a valid example.

I can't recall ever seeing anyone claim tha...
The Generalized Anti-Zombie Principle
by Eliezer Yudkowsky — 2008-04-05T23:16:30.000Z

"Each problem that I solved became a rule which served afterwards to solve other problems."
—Rene Descartes, Discours de la Methode

"Zombies" are putatively beings that are atom-by-atom identical to us, governed by all the same third-party-visible physical laws, except that they are not conscious.

Though the philosophy is complicated, the core argument against zombies is simple: When you focus your inward awareness on your inward awareness, soon after your internal narrative (the little voice inside your head that speaks your thoughts) says "I am aware of being aware", and then you say it out loud, and then you type it into a computer keyboard, and create a third-party visible blog post.

Consciousness, whatever it may be—a substance, a process, a name for a confusion—is not epiphenomenal; your mind can catch the inner listener in the act of listening, and say so out loud. The fact that I have typed this paragraph would at least seem to refute the idea that consciousness has no experimentally detectable consequences.

I hate to say "So now let's accept this and move on," over such a philosophically controversial question, but it seems like a considerable majority of Overcoming Bias commenters do accept this. And there are other conclusions you can only get to after you accept that you cannot subtract consciousness and leave the universe looking exactly the same. So now let's accept this and move on.

The form of the Anti-Zombie Argument seems like it should generalize, becoming an Anti-Zombie Principle. But what is the proper generalization?

Let's say, for example, that someone says: "I have a switch in my hand, which does not affect your brain in any way; and iff this switch is flipped, you will cease to be conscious." Does the Anti-Zombie Principle rule this out as well, with the same structure of argument?

It appears to me that in the case above, the answer is yes. In particular, you can say: "Even after your switch is flipped, I will still talk about consciousness for exactly the same reasons I did before. If I am conscious right now, I will still be conscious after you flip the switch."

Philosophers may object, "But now you're equating consciousness with talking about consciousness! What about the Zombie Master, the chatbot that regurgitates a rem...
Zombie Responses
by Eliezer Yudkowsky — 2008-04-05T00:42:24.000Z

I'm a bit tired today, having stayed up until 3AM writing yesterday's >6000-word post on zombies, so today I'll just reply to Richard, and tie up a loose end I spotted the next day.

Besides, TypePad's nitwit, un-opt-out-able 50-comment pagination "feature", that doesn't work with the Recent Comments sidebar, means that we might as well jump the discussion here before we go over the 50-comment limit.

(A) Richard Chappell writes:

A terminological note (to avoid unnecessary confusion): what you call 'conceivable', others of us would merely call "apparently conceivable".

The gap between "I don't see a contradiction yet" and "this is logically possible" is so huge (it's NP-complete even in some simple-seeming cases) that you really should have two different words. As the zombie argument is boosted to the extent that this huge gap can be swept under the rug of minor terminological differences, I really think it would be a good idea to say "conceivable" versus "logically possible" or maybe even have a still more visible distinction. I can't choose professional terminology that has already been established, but in a case like this, I might seriously refuse to use it.

Maybe I will say "apparently conceivable" for the kind of information that zombie advocates get by imagining Zombie Worlds, and "logically possible" for the kind of information that is established by exhibiting a complete model or logical proof. Note the size of the gap between the information you can get by closing your eyes and imagining zombies, and the information you need to carry the argument for epiphenomenalism.

That is, your view would be characterized as a form of Type-A materialism, the view that zombies are not even (genuinely) conceivable, let alone metaphysically possible.

Type-A materialism is a large bundle; you shouldn't attribute the bundle to me until you see me agree with each of the parts. I think that someone who asks "What is consciousness?" is asking a legitimate question, has a legitimate demand for insight; I don't necessarily think that the answer takes the form of "Here is this stuff that has all the properties you would attribute to consciousness, for such-and-such reason", but may to some extent consist of insights that cause you to realize you were asking the question the wrong way.

This is not being eliminative about consciousness. I...
Zombies! Zombies?
by Eliezer Yudkowsky — 2008-04-04T09:55:26.000Z

Your "zombie", in the philosophical usage of the term, is putatively a being that is exactly like you in every respect—identical behavior, identical speech, identical brain; every atom and quark in exactly the same position, moving according to the same causal laws of motion—except that your zombie is not conscious.

It is furthermore claimed that if zombies are "possible" (a term over which battles are still being fought), then, purely from our knowledge of this "possibility", we can deduce a priori that consciousness is extra-physical, in a sense to be described below; the standard term for this position is "epiphenomenalism".

(For those unfamiliar with zombies, I emphasize that this is not a strawman. See, for example, the SEP entry on Zombies. The "possibility" of zombies is accepted by a substantial fraction, possibly a majority, of academic philosophers of consciousness.)

I once read somewhere, "You are not the one who speaks your thoughts—you are the one who hears your thoughts". In Hebrew, the word for the highest soul, that which God breathed into Adam, is N'Shama—"the hearer".

If you conceive of "consciousness" as a purely passive listening, then the notion of a zombie initially seems easy to imagine. It's someone who lacks the N'Shama, the hearer.

(Warning: Long post ahead. Very long 6,600-word post involving David Chalmers ahead. This may be taken as my demonstrative counterexample to Richard Chappell's Arguing with Eliezer Part II, in which Richard accuses me of not engaging with the complex arguments of real philosophers. Edit December 2019: There now exists a shorter edited version of this post here)

When you open a refrigerator and find that the orange juice is gone, you think "Darn, I'm out of orange juice." The sound of these words is probably represented in your auditory cortex, as though you'd heard someone else say it. (Why do I think this? Because native Chinese speakers can remember longer digit sequences than English-speakers. Chinese digits are all single syllables, and so Chinese speakers can remember around ten digits, versus the famous "seven plus or minus two" for English speakers. There appears to be a loop of repeating sounds back to yourself, a size limit on working memory in the auditory cortex, which is genuinely phoneme-based.)

Let's sup...
Reductive Reference
by Eliezer Yudkowsky — 2008-04-03T01:37:39.000Z

The reductionist thesis (as I formulate it) is that human minds, for reasons of efficiency, use a multi-level map in which we separately think about things like "atoms" and "quarks", "hands" and "fingers", or "heat" and "kinetic energy". Reality itself, on the other hand, is single-level in the sense that it does not seem to contain atoms as separate, additional, causally efficacious entities over and above quarks.

Sadi Carnot formulated the (precursor to) the second law of thermodynamics using the caloric theory of heat, in which heat was just a fluid that flowed from hot things to cold things, produced by fire, making gases expand—the effects of heat were studied separately from the science of kinetics, considerably before the reduction took place. If you're trying to design a steam engine, the effects of all those tiny vibrations and collisions which we name "heat" can be summarized into a much simpler description than the full quantum mechanics of the quarks. Humans compute efficiently, thinking of only significant effects on goal-relevant quantities.

But reality itself does seem to use the full quantum mechanics of the quarks. I once met a fellow who thought that if you used General Relativity to compute a low-velocity problem, like an artillery shell, GR would give you the wrong answer—not just a slow answer, but an experimentally wrong answer—because at low velocities, artillery shells are governed by Newtonian mechanics, not GR. This is exactly how physics does not work. Reality just seems to go on crunching through General Relativity, even when it only makes a difference at the fourteenth decimal place, which a human would regard as a huge waste of computing power. Physics does it with brute force. No one has ever caught physics simplifying its calculations—or if someone did catch it, the Matrix Lords erased the memory afterward.

Our map, then, is very much unlike the territory; our maps are multi-level, the territory is single-level. Since the representation is so incredibly unlike the referent, in what sense can a belief like "I am wearing socks" be called true, when in reality itself, there are only quarks?

In case you've forgotten what the word "true" means, the classic definition was given by Alfred Tarski:

The statement "snow is white" is true if and only if snow is whi

...
Brain Breakthrough! It's Made of Neurons!
by Eliezer Yudkowsky — 2008-04-01T19:00:59.000Z

In an amazing breakthrough, a multinational team of scientists led by Nobel laureate Santiago Ramón y Cajal announced that the brain is composed of a ridiculously complicated network of tiny cells connected to each other by infinitesimal threads and branches.

The multinational team—which also includes the famous technician Antonie van Leeuwenhoek, and possibly Imhotep, promoted to the Egyptian god of medicine—issued this statement:

"The present discovery culminates years of research indicating that the convoluted squishy thing inside our skulls is even more complicated than it looks. Thanks to Cajal's application of a new staining technique invented by Camillo Golgi, we have learned that this structure is not a continuous network like the blood vessels of the body, but is actually composed of many tiny cells, or "neurons", connected to one another by even more tiny filaments.

"Other extensive evidence, beginning from Greek medical researcher Alcmaeon and continuing through Paul Broca's research on speech deficits, indicates that the brain is the seat of reason.

"Nemesius, the Bishop of Emesia, has previously argued that brain tissue is too earthy to act as an intermediary between the body and soul, and so the mental faculties are located in the ventricles of the brain. However, if this is correct, there is no reason why this organ should turn out to have an immensely complicated internal composition.

"Charles Babbage has independently suggested that many small mechanical devices could be collected into an 'Analytical Engine', capable of performing activities, such as arithmetic, which are widely believed to require thought. The work of Luigi Galvani and Hermann von Helmholtz suggests that the activities of neurons are electrochemical in nature, rather than mechanical pressures as previously believed. Nonetheless, we think an analogy with Babbage's 'Analytical Engine' suggests that a vastly complicated network of neurons could similarly exhibit thoughtful properties.

"We have found an enormously complicated material system located where the mind should be. The implications are shocking, and must be squarely faced. We believe that the present research offers strong experimental evidence that Benedictus Spinoza was correct, and René Descartes wrong: Mind and body are of one substance.

"In combination ...
Heat vs. Motion
by Eliezer Yudkowsky — 2008-04-01T03:55:19.000Z

After yesterday's post, it occurred to me that there's a much simpler example of reductionism jumping a gap of apparent-difference-in-kind: the reduction of heat to motion.

Today, the equivalence of heat and motion may seem too obvious in hindsight—everyone says that "heat is motion", therefore, it can't be a "weird" belief.

But there was a time when the kinetic theory of heat was a highly controversial scientific hypothesis, contrasting to belief in a caloric fluid that flowed from hot objects to cold objects. Still earlier, the main theory of heat was "Phlogiston!"

Suppose you'd separately studied kinetic theory and caloric theory. You now know something about kinetics: collisions, elastic rebounds, momentum, kinetic energy, gravity, inertia, free trajectories. Separately, you know something about heat: Temperatures, pressures, combustion, heat flows, engines, melting, vaporization.

Not only is this state of knowledge a plausible one, it is the state of knowledge possessed by e.g. Sadi Carnot, who, working strictly from within the caloric theory of heat, developed the principle of the Carnot cycle—a heat engine of maximum efficiency, whose existence implies the second law of thermodynamics. This in 1824, when kinetics was a highly developed science.

Suppose, like Carnot, you know a great deal about kinetics, and a great deal about heat, as separate entities. Separate entities of knowledge, that is: your brain has separate filing baskets for beliefs about kinetics and beliefs about heat. But from the inside, this state of knowledge feels like living in a world of moving things and hot things, a world where motion and heat are independent properties of matter.

Now a Physicist From The Future comes along and tells you: "Where there is heat, there is motion, and vice versa. That's why, for example, rubbing things together makes them hotter."

There are (at least) two possible interpretations you could attach to this statement, "Where there is heat, there is motion, and vice versa."

First, you could suppose that heat and motion exist separately—that the caloric theory is correct—but that among our universe's physical laws is a "bridging law" which states that, where objects are moving quickly, caloric will come into existence. And conversely, another bridging law says that caloric can ex...
Angry Atoms
by Eliezer Yudkowsky — 2008-03-31T00:28:10.000Z

Fundamental physics—quarks 'n stuff—is far removed from the levels we can see, like hands and fingers. At best, you can know how to replicate the experiments which show that your hand (like everything else) is composed of quarks, and you may know how to derive a few equations for things like atoms and electron clouds and molecules.

At worst, the existence of quarks beneath your hand may just be something you were told. In which case it's questionable in one what sense you can be said to "know" it at all, even if you repeat back the same word "quark" that a physicist would use to convey knowledge to another physicist.

Either way, you can't actually see the identity between levels—no one has a brain large enough to visualize avogadros of quarks and recognize a hand-pattern in them.

But we at least understand what hands do. Hands push on things, exert forces on them. When we're told about atoms, we visualize little billiard balls bumping into each other. This makes it seem obvious that "atoms" can push on things too, by bumping into them.

Now this notion of atoms is not quite correct. But so far as human imagination goes, it's relatively easy to imagine our hand being made up of a little galaxy of swirling billiard balls, pushing on things when our "fingers" touch them. Democritus imagined this 2400 years ago, and there was a time, roughly 1803-1922, when Science thought he was right.

But what about, say, anger?

How could little billiard balls be angry? Tiny frowny faces on the billiard balls?

Put yourself in the shoes of, say, a hunter-gatherer—someone who may not even have a notion of writing, let alone the notion of using base matter to perform computations—someone who has no idea that such a thing as neurons exist. Then you can imagine the functional gap that your ancestors might have perceived between billiard balls and "Grrr! Aaarg!"

Forget about subjective experience for the moment, and consider the sheer behavioral gap between anger and billiard balls. The difference between what little billiard balls do, and what anger makes people do. Anger can make people raise their fists and hit someone—or say snide things behind their backs—or plant scorpions in their tents at night. Billiard balls just push on things.

Try to put yourself in the shoes of the hu...