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?

In Figure 1, we see, at A, a half-silvered mirror, and two photon detectors, Detector 1 and Detector 2.

Early scientists, when they ran experiments like this, became confused about what the results meant. They would send a photon toward the half-silvered mirror, and half the time they would see Detector 1 click, and the other half of the time they would see Detector 2 click.

The early scientists—you’re going to laugh at this—thought that the silver mirror deflected the photon half the time, and let it through half the time.

Ha, ha! As if the half-silvered mirror did different things on different occasions! I want you to let go of this idea, because if you cling to what early scientists thought, you will become extremely confused. The half-silvered mirror obeys the same rule every time.

If you were going to write a computer program that was this experiment— not a computer program that predicted the result of the experiment, but a computer program that resembled the underlying reality—it might look sort of like this:

At the start of the program (the start of the experiment, the start of time) there’s a certain mathematical entity, called a configuration. You can think of this configuration as corresponding to “there is one photon heading from the photon source toward the half-silvered mirror,” or just “a photon heading toward A.”

A configuration can store a single complex value—“complex” as in the complex numbers , with i defined as . At the start of the program, there’s already a complex number stored in the configuration “a photon heading toward A.” The exact value doesn’t matter so long as it’s not zero. We’ll let the configuration “a photon heading toward A” have a value of .

All this is a fact within the territory, not a description of anyone’s knowledge. A configuration isn’t a proposition or a possible way the world could be. A configuration is a variable in the program—you can think of it as a kind of memory location whose index is “a photon heading toward A”—and it’s out there in the territory.

As the complex numbers that get assigned to configurations are not positive real numbers between 0 and 1, there is no danger of confusing them with probabilities. “A photon heading toward A” has complex value −1, which is hard to see as a degree of belief. The complex numbers are values within the program, again out there in the territory. We’ll call the complex numbers amplitudes.

There are two other configurations, which we’ll call “a photon going from A to Detector 1” and “a photon going from A to Detector 2.” These configurations don’t have a complex value yet; it gets assigned as the program runs.

We are going to calculate the amplitudes of “a photon going from A toward 1” and “a photon going from A toward 2” using the value of “a photon going toward A,” and the rule that describes the half-silvered mirror at A.

Roughly speaking, the half-silvered mirror rule is “multiply by 1 when the photon goes straight, and multiply by i when the photon turns at a right angle.” This is the universal rule that relates the amplitude of the configuration of “a photon going in,” to the amplitude that goes to the configurations of “a photon coming out straight” or “a photon being deflected.”[1]

So we pipe the amplitude of the configuration “a photon going toward A,” which is , into the half-silvered mirror at A, and this transmits an amplitude of to “a photon going from A toward 1,” and also transmits an amplitude of to “a photon going from A toward 2.”

In the Figure 1 experiment, these are all the configurations and all the transmitted amplitude we need to worry about, so we’re done. Or, if you want to think of “Detector 1 gets a photon” and “Detector 2 gets a photon” as separate configurations, they’d just inherit their values from “A to 1” and “A to 2” respectively. (Actually, the values inherited should be multiplied by another complex factor, corresponding to the distance from A to the detector; but we will ignore that for now, and suppose that all distances traveled in our experiments happen to correspond to a complex factor of 1.)

So the final program state is:

Configuration “a photon going toward A”: (−1+0i)
Configuration “a photon going from A toward 1”: (0−i)
Configuration “a photon going from A toward 2”: (−1+0i)

and optionally

Configuration “Detector 1 gets a photon”: (0−i)
Configuration “Detector 2 gets a photon”: (−1+0i).

This same result occurs—the same amplitudes stored in the same configurations—every time you run the program (every time you do the experiment).

Now, for complicated reasons that we aren’t going to go into here— considerations that belong on a higher level of organization than fundamental quantum mechanics, the same way that atoms are more complicated than quarks—there’s no simplemeasuring instrument that can directly tell us the exact amplitudes of each configuration. We can’t directly see the program state.

So how do physicists know what the amplitudes are?

We do have a magical measuring tool that can tell us the squared modulus of a configuration’s amplitude. If the original complex amplitude is , we can get the positive real number . Think of the Pythagorean theorem: if you imagine the complex number as a little arrow stretching out from the origin on a two-dimensional plane, then the magic tool tells us the squared length of the little arrow, but it doesn’t tell us the direction the arrow is pointing.

To be more precise, the magic tool actually just tells us the ratios of the squared lengths of the amplitudes in some configurations. We don’t know how long the arrows are in an absolute sense, just how long they are relative to each other. But this turns out to be enough information to let us reconstruct the laws of physics—the rules of the program. And so I can talk about amplitudes, not just ratios of squared moduli.

When we wave the magic tool over “Detector 1 gets a photon” and “Detector 2 gets a photon,” we discover that these configurations have the same squared modulus—the lengths of the arrows are the same. Thus speaks the magic tool. By doing more complicated experiments (to be seen shortly), we can tell that the original complex numbers had a ratio of i to 1.

And what is this magical measuring tool?

Well, from the perspective of everyday life—way, way, way above the quantum level and a lot more complicated—the magical measuring tool is that we send some photons toward the half-silvered mirror, one at a time, and count up how many photons arrive at Detector 1 versus Detector 2 over a few thousand trials. The ratio of these values is the ratio of the squared moduli of the amplitudes. But the reason for this is not something we are going to consider yet. Walk before you run. It is not possible to understand what happens all the way up at the level of everyday life, before you understand what goes on in much simpler cases.

For today’s purposes, we have a magical squared-modulus-ratio reader. And the magic tool tells us that the little two-dimensional arrow for the configuration “Detector 1 gets a photon” has the same squared length as for “Detector 2 gets a photon.” That’s all.

You may wonder, “Given that the magic tool works this way, what motivates us to use quantum theory, instead of thinking that the half-silvered mirror reflects the photon around half the time?”

Well, that’s just begging to be confused—putting yourself into a historically realistic frame of mind like that and using everyday intuitions. Did I say anything about a little billiard ball going one way or the other and possibly bouncing off a mirror? That’s not how reality works. Reality is about complex amplitudes flowing between configurations, and the laws of the flow are stable.

But if you insist on seeing a more complicated situation that billiard-ball ways of thinking can’t handle, here’s a more complicated experiment.

In Figure 2, B and C are full mirrors, and A and D are half-mirrors. The line from D to E is dashed for reasons that will become apparent, but amplitude is flowing from D to E under exactly the same laws.

Now let’s apply the rules we learned before:

At the beginning of time “a photon heading toward A” has amplitude .

We proceed to compute the amplitude for the configurations “a photon going from A to B” and “a photon going from A to C”:

“a photon going from A to B” = a photon heading toward A” =

Similarly,

“a photon going from A to C” = 1 a photon heading toward A” =

The full mirrors behave (as one would expect) like half of a half-silvered mirror—a full mirror just bends things by right angles and multiplies them by i. (To state this slightly more precisely: For a full mirror, the amplitude that flows, from the configuration of a photon heading in, to the configuration of a photon heading out at a right angle, is multiplied by a factor of i.)

So:

“a photon going from B to D = “a photon going from A to B = ,
“a photon going from C to D = “a photon going from A to C =

“B to D and “C to D are two different configurations—we don’t simply write “a photon at D—because the photons are arriving at two different angles in these two different configurations. And what D does to a photon depends on the angle at which the photon arrives.

Again, the rule (speaking loosely) is that when a half-silvered mirror bends light at a right angle, the amplitude that flows from the photon-going-in configuration to the photon-going-out configuration, is the amplitude of the photon-going-in configuration multiplied by i. And when two configurations are related by a half-silvered mirror letting light straight through, the amplitude that flows from the photon-going-in configuration is multiplied by 1.

So:

From the configuration “a photon going from B to D,” with original amplitude(1+0i)

Amplitude of flows to “a photon going from D to E.
Amplitude of flows to “a photon going from D to F. ”

From the configuration “a photon going from C to D,” with original amplitude(0−i)

Amplitude of flows to “a photon going from D to F.
Amplitude of flows to “a photon going from D to E.

Therefore:

• The total amplitude flowing to configuration “a photon going from D to E” is .

• The total amplitude flowing to configuration “a photon going from D to F” is .

(You may want to try working this out yourself on pen and paper if you lost track at any point.)

But the upshot, from that super-high-level “experimental” perspective that we think of as normal life, is that we see no photons detected at E. Every photon seems to end up at F. The ratio of squared moduli between “D to E” and “D to F” is 0 to 4. That’s why the line from D to E is dashed, in this figure.

This is not something it is possible to explain by thinking of half-silvered mirrors deflecting little incoming billiard balls half the time. You’ve got to think in terms of amplitude flows.

If half-silvered mirrors deflected a little billiard ball half the time, in this setup, the little ball would end up at Detector 1 around half the time and Detector 2 around half the time. Which it doesn’t. So don’t think that.

You may say, “But wait a minute! I can think of another hypothesis that accounts for this result. What if, when a half-silvered mirror reflects a photon, it does something to the photon that ensures it doesn’t get reflected next time? And when it lets a photon go through straight, it does something to the photon so it gets reflected next time.”

Now really, there’s no need to go making the rules so complicated. Occam’s Razor, remember. Just stick with simple, normal amplitude flows between configurations.

But if you want another experiment that disproves your new alternative hypothesis, it’s Figure 3.

Here, we’ve left the whole experimental setup the same, and just put a little blocking object between B and D. This ensures that the amplitude of “a photon going from B to D” is 0.

Once you eliminate the amplitude contributions from that configuration, you end up with totals of in “a photon going from D to F, ” and in “a photon going from D to E.”

The squared moduli of and are both 1, so the magic measuring tool should tell us that the ratio of squared moduli is 1. Way back up at the level where physicists exist, we should find that Detector 1 goes off half the time, and Detector 2 half the time.

The same thing happens if we put the block between C and D. The amplitudes are different, but the ratio of the squared moduli is still 1, so Detector 1 goes off half the time and Detector 2 goes off half the time.

This cannot possibly happen with a little billiard ball that either does or doesn’t get reflected by the half-silvered mirrors.

Because complex numbers can have opposite directions, like 1 and −1, or i and −i, amplitude flows can cancel each other out. Amplitude flowing from configuration X into configuration Y can be canceled out by an equal and opposite amplitude flowing from configuration Z into configuration Y. In fact, that’s exactly what happens in this experiment.

In probability theory, when something can either happen one way or another, X or ¬X, then . And all probabilities are positive. So if you establish that the probability of Z happening given X is , and the probability of X happening is , then the total probability of Z happening is at least no matter what goes on in the case of ¬X. There’s no such thing as negative probability, less-than-impossible credence, or credibility, so degrees of belief can’t cancel each other out like amplitudes do.

Not to mention that probability is in the mind to begin with; and we are talking about the territory, the program-that-is-reality, not talking about human cognition or states of partial knowledge.

By the same token, configurations are not propositions, not statements, not ways the world could conceivably be. Configurations are not semantic constructs. Adjectives like probable do not apply to them; they are not beliefs or sentences or possible worlds. They are not true or false but simply real.

In the experiment of Figure 2, do not be tempted to think anything like: “The photon goes to either B or C, but it could have gone the other way, and this possibility interferes with its ability to go to E…”

It makes no sense to think of something that “could have happened but didn’t” exerting an effect on the world. We can imagine things that could have happened but didn’t—like thinking, “Gosh, that car almost hit me”—and our imagination can have an effect on our future behavior. But the event of imagination is a real event, that actually happens, and that is what has the effect. It’s your imagination of the unreal event—your very real imagination, implemented within a quite physical brain—that affects your behavior.

To think that the actual event of a car hitting you—this event which could have happened to you, but in fact didn’t—is directly exerting a causal effect on your behavior, is mixing up the map with the territory.

What affects the world is real. (If things can affect the world without being “real,” it’s hard to see what the word “real” means.) Configurations and amplitude flows are causes, and they have visible effects; they are real. Configurations are not possible worlds and amplitudes are not degrees of belief, any more than your chair is a possible world or the sky is a degree of belief.

So what is a configuration, then?

Well, you’ll be getting a clearer idea of that in later essays.

But to give you a quick idea of how the real picture differs from the simplified version we saw in this essay…

Our experimental setup only dealt with one moving particle, a single photon. Real configurations are about multiple particles. The next essay will deal with the case of more than one particle, and that should give you a much clearer idea of what a configuration is.

Each configuration we talked about should have described a joint position of all the particles in the mirrors and detectors, not just the position of one photon bopping around.

In fact, the really real configurations are over joint positions of all the particles in the universe, including the particles making up the experimenters. You can see why I’m saving the notion of experimental results for later essays.

In the real world, amplitude is a continuous distribution over a continuous space of configurations. This essay’s “configurations” were blocky and digital, and so were our “amplitude flows.” It was as if we were talking about a photon teleporting from one place to another.

If none of that made sense, don’t worry. It will be cleared up in later essays. Just wanted to give you some idea of where this was heading.

1. [Editor’s Note: Strictly speaking, a standard half-silvered mirror would yield a rule “multiply by −1 when the photon turns at a right angle,” not “multiply by i.” The basic scenario described by the author is not physically impossible, and its use does not affect the substantive argument. However, physics students may come away confused if they compare the discussion here to textbook discussions of Mach–Zehnder interferometers. We’ve left this idiosyncrasy in the text because it eliminates any need to specify which side of the mirror is half-silvered, simplifying the experiment.]

• Eliezer, in case you plan to discuss Bell’s-inequality-type experiments in future posts, I suggest that you use the GHZ state (not the EPR pair) to show how local realism is ruled out in QM. The GHZ state is a much cleaner result, and is not obscurred by the statistics inherent in Bell’s inequality.

• I think some of my readers may be overestimating the degree to which I intend to explain quantum mechanics, here. I’m not doing a textbook. I’m trying to get (reasonably smart nonphysicist) readers to the point where they’re no longer confused, and the remaining difficulties are mere matters of math.

Still a useful suggestion though, thanks.

• A configuration can store a single complex value—“complex” as in the complex numbers (a + bi).
Any complex number? I.e. you’re invoking an uncountable infinity for explaining the lowest known layer of physics? How does that fit in with being an infinite-set atheist—assuming you still hold that position?
I’m speaking as a nonphysicist reader, so I may well be missing something awfully obvious here. Any clarification would be appreciated.

• Eliezer (and Robin) this series is very interesting and all, but.… aren’t you writing this on the wrong blog?

I used to like this blog better when it was all about overcoming bias

• Any complex number? I.e. you’re invoking an uncountable infinity for explaining the lowest known layer of physics? How does that fit in with being an infinite-set atheist—assuming you still hold that position?

In case you didn’t notice, he’s talking about a complex number, not all the complex numbers.

• So… I’m confused. You say:

″...the half-silvered mirror rule is “Multiply by 1 when the photon goes straight, and multiply by i when the photon turns at a right angle.”

We appear to have defined everything needful, except the word “when”.

Accepting that we are just performing ‘operations’ on ‘configurations’, what decides which operation will be performed? Is it the configuration of the incoming photon? Is it some magical (i.e.quantum) property of a half of a silver?

• It was intended to be clear that all operations are performed and propagated throughout the entire system, I think.

• I was confused about it too, but understood that what is meant is, that the ‘half-silvered mirror rule’ is a rule that does two things at once, namely x: (x*1, x*i), so it’s a multi-valued operation.

• Eliezer, I realise there’s still a way to go, but I just wanted to let you know that this is already much more useful than any conversion I’ve had about QM with anyone in the past. Thank you.

Eadwacer, I might be wrong, but I’d assumed both operations are always performed.

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• This brilliant young mathematician can speak to you in more familiar terms and has all the math “to back up what he says.”

I looked at a few of his essays and didn’t find any substantial mathematics in them, brilliant or otherwise. In the process I came across assertions that for a particle in a circular orbit, v = 2 pi r/​t is false for the traditional value of pi, which in this kinematic situation must have the value 4. Oh, and modern physics is a conspiracy of the intelligence communities to prevent dangerous discoveries being made. (Hm, is modern AGI a conspiracy of the SIAI to prevent UFAI?)

Crackpot. He claims to have many pseudonyms; is “MonkeyMind” one of them?

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• The entire thread was deleted, but you can still read parts of it in the history.

• I can see the banned comments, but yeah. I actually read or at least skim literally every comment and post on LW, so I’ve been sitting back for a while now.

• Then someone should probably know about the privilege escalation bug that allows us plebs to read banned comments.

• You also see banned comments? I think the person to notify is Matt of Tricycle.

• The ability to see banned comments on userpages (but nowhere else) is a feature.

(Someone taking the active step of clicking on a username presumably has a specific interest in seeing the comments, and ought to be able to.)

• I think Alicorn understood paper-machine to be claiming to see deleted comments in-place. I also think this because going to someone’s user page and seeing banned comments does not seem like the kind of activity that would count as a “privilege escalation bug”.

• Depends on why the comments were banned. If it’s because they disclosed information which shouldn’t have been disclosed...

• Comments were banned simply because thumbs down indicated that people did not want to read them. CENSORSHIP because no one had to read what I wrote. They knew exactly what they would get when they returned to the thread as I was consistent throughout.

Although the mod asked me not to post. Another senior member pm’d me and suggested that I post less often and try to add something to a discussion that was agreeable to other participants. SO I’d wait a few weeks and then added comments including information from mathematicians in support of my conclusions, thinking that this would be more acceptable. Since it was not, I can only conclude that people are just NOT open to the different pov that I have.

“those enabling them by responding to them should stop.and (A specific suggestion I have is to establish a community norm of downvoting those participating in hopeless conversations, even if their contributions are high-quality.)

ADDED: What is sad, is that I wanted to talk about the OP, amplitudes and configurations, and everyone else keep wanting to talk about me, and have me read other sequences, etc. The false conclusions others have made about GPS just needed to be addressed as well as many other points, but I’ll leave it alone. It is obvious no matter how much water flows under the bridge, I will be censored. Folks here are not interested in discussing the erroneous conclusions of the virtual half-silvered mirror experiment.

• So what’s up with that? I went to a lot of work writing those posts.

Is this the sort of thing done with approval of the site owner?

They were well thot out and reasoned posts. The majority were very civil and violated no posted rules. In fact there aren’t any posted rules that I am aware of. Just because my posts are annoying to some folks is not reason to delete them. NO one has to read anything.

I just don’t understand the reasoning there, or here:

“A specific suggestion I have is to establish a community norm of downvoting those participating in hopeless conversations, even if their contributions are high-quality.”

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• Dude, I am a mod. I don’t like slinging the banhammer around as a first resort, but you’re annoying.

• I would be shocked if Eliezer did anything to straighten us out if he ever looked into the matter.

• It would depend, I think, on how one resolves the conflict between Friendliness and the human value of self-determination.

• For a rather silly reason, I wrote something about:

… explaining the lowest known layer of physics …
Please ignore the “lowest known layer” part. I accidentally committed a mind projection fallacy while writing that comment.

• as far as uncountable complex states… well, the actual complex values don’t matter so much as the relative phases. Maybe best to think about it almost as a geometrical principle, of sorts.

Here I’m just speculating, but maybe relative phase (that is, angle when representing the complex value in polar notation) can only be shifted by rational amounts? That is, the relative phase between thingie 1 and thingie 2 is x*2Pi, where x must be rational?

I’m not saying this is the way it is, but I can certainly see, based on my, as of yet, limited knowledge, that it could be that way.

• I guess, Eliezer, that I would be concerned about convincing everyone that the universe runs along like a computer, computing amplitudes locally (which seems to be the gist of your discussion). To do so would certainly make people feel like QM isn’t confusing; it would just be wave mechanics. But this would give people a false confidence, I think, and is not how the universe appears to operate.

But this is the first post, so I’ll try to confine my criticism until you’ve wrapped up your discussion.

• aren’t you writing this on the wrong blog?

As far as I know Robin doesn’t actually have a separate economics blog and he seems to drop any economics topic that interests him into this one, so neither Eliezer nor Robin always stick closely to the “bias” theme. Does it really matter?

• Jess: You mean that physics, as we understand it, absolutely requires that there will exist complex phase differences such that when divided by 2*Pi, the result will be irrational?

Oh well then, bang goes that idea. :)

• Eadwacer: Accepting that we are just performing ‘operations’ on ‘configurations’, what decides which operation will be performed? Is it the configuration of the incoming photon? Is it some magical (i.e.quantum) property of a half of a silver?

Amplitude flows to both end configurations, every time. That is the law of the amplitude flows. It is not one or the other.

Sebastian: Any complex number? I.e. you’re invoking an uncountable infinity for explaining the lowest known layer of physics? How does that fit in with being an infinite-set atheist—assuming you still hold that position?

Infinite set atheism is not part of standard physics. Probably the best hope for reconciling infinite set atheism with a continuous universe is some equivalent of holographic theory that bounds the total information, meaning, you could always describe a wavefunction with some finite number of bits. I doubt I’m going to go into that. ’sides, my infinite set atheism could simply be wrong.

Jeremy: I was a little disturbed when you offered up the experiment that allowed us to reject the hypothesis about a half-mirror changing each time it reflects a photon or lets one through. How do we know there aren’t other experiments that could discredit the amplitude hypothesis? I’m sure there’s a good answer, but don’t expect me to take too much on faith.

Obviously, real physics is based on a hell of a lot more experiments narrowing things down than just the ones I’m describing here. This is not the evidence. This is just here to help you interpret what the real evidence is evidence for. To see how the theory was nailed down historically by replicable experiments, you would have to read real physics books. This series is not about presenting the full evidence for QM as a hypothesis, it is about rendering the hypothesis itself non-confusing. This is my ambitious goal.

• I’m sorry; I’m still a bit confused by this. “Amplitude flows to both end configurations every time,” so when a single photon is fired (as in figure 1), I agree that the amplitudes of A->1 and A->2 are both 1. Does that mean both detectors click? (I was under the impression that only one detector would click.)

• “The detector” is not a machine for “measuring the amplitude”. In fact, we have no way of “measuring the amplitude”. The only tool we have “measures the ratios of the squares of the amplitudes”, and that tool is this: “run the simulation a bunch of times and compute the ratio of detections at 1 to detections at 2”.

• Psy-Kosh: I have never heard of anyone ever successfully formulating quantum (or classical) mechanics without the full spectrum of real numbers. You can’t even have simple things, like right triangles with non-integer side length, without irrational numbers to “fill in the gaps”. Any finite-set formulation of QM would look very different from what we understand now.

• Psy-Kosh: I have never heard of anyone ever successfully formulating quantum (or classical) mechanics without the full spectrum of real numbers. You can’t even have simple things, like right triangles with non-integer side length, without irrational numbers to “fill in the gaps”. Any finite-set formulation of QM would look very different from what we understand now.

• Eliezer,

I’ve found that Jaynes’s infinite set atheism is a little too extreme. It forces you to take the slow route every time when you want to explore stochastic process priors like Gaussian process and Dirichlet process priors. I reserve infinite set atheism for observables—no infinite sets of observations allowed.

• Jess: Basically, my (extremely vague) notion was that since there’s a “planck time” below which little (as far as we know) can be meaningfully said, effectively all quantum operations/​changes over time/​whatever are integer number of some “planck” versions of themselves, or combinations theirof.

Soooooo..… maybe.… possibly… there may be some sort of “quantum of phase shift”… But I concede that it was just speculation on my part based on vague notions.

Oh well, thanks. :) (would be slick if it actually did work out that way, sounds like, from you, that may not be much of an option)

• Just so everyone’s on the same page, continuum atheism doesn’t entail disbelief in all irrationals. The hypoteneuse of a right triangle, pi and e are all in the countable set of computable reals.

• If a photon hits two full mirrors at right angles, then its amplitude is changed by i*i = −1. Does it matter whether the second mirror turns the photon back towards its source, or causes the photon to continue in the direction it was going originally? Do you get −1 in both cases?

• Okay, what happens in this situation: Take figure 2. The arrow coming in from the left? Replace it with figure 1, with its mirror relabeled E and detector 2 removed (replaced with figure 2). And lengthen the distance to detector 1 so that it’s equal to the total distance to detector 2 in figure 2. And I guess call the detector 1 in figure 2 “X” for “we know you won’t be getting any amplitude”. Now what? Here’s what I get...

A photon is coming toward E (-1,0)

A photon is coming from E to 1 (0,-1) A photon is coming from E to A (-1,0)

A photon is coming from E to 1 (0,-1) A photon is coming from A to B (0,-1) A photon is coming from A to C (-1,0)

A photon is coming from E to 1 (0,-1) A photon is coming from B to D (1,0) A photon is coming from C to D (0,-1)

A photon is coming from E to 1 (0,-1) A photon is coming from D to X (0,1)+(0,-1) = (0,0) A photon is coming from D to 2 (1,0)+(1,0) = (2,0)

From this I conclude that detector 1 will register a hit 15 of the time and detector 2 will register a hit 45 of the time. Is that correct?

• Here’s what I was missing: the magnitudes of the amplitudes needs to decrease when changing from one possible state to more than one. In drawing-on-2d terms, a small amount of dark pencil must change to a large amount of lighter pencil, not a large amount of equally dark pencil. So here’s what actually occurs (I think):

A photon is coming toward E (-1,0)

A photon is coming from E to 1 (0,-1/​sqrt(2)) A photon is coming from E to A (-1/​sqrt(2),0)

A photon is coming from E to 1 (0,-1/​sqrt(2)) A photon is coming from A to B (0,-1/​2) A photon is coming from A to C (-1/​2,0)

A photon is coming from E to 1 (0,-1/​sqrt(2)) A photon is coming from B to D (1/​2,0) A photon is coming from C to D (0,-1/​2)

A photon is coming from E to 1 (0,-1/​sqrt(2)) A photon is coming from D to X (0,1/​2sqrt(2))+(0,-1/​2sqrt(2)) = (0,0) A photon is coming from D to 2 (1/​2sqrt(2),0)+(1/​2sqrt(2),0) = (1/​sqrt(2),0)

Detector 1 hits 12 of the time and detector 2 hits 12 of the time.

• What I was about to say. It really doesn’t matter yet, but it’s better to get the reader used to unitarity straight away. (Though I wouldn’t explicitly mention unitarity this early—I’d just replace the rule with “Multiply by 1/​sqrt(2) when the photon goes straight, and multiply by i/​sqrt(2) when the photon turns at a right angle” and everything that follows from that. If the maths gets too complicated with all those denominators, just make the initial amplitude -sqrt(2) rather than −1.)

• The prediction for what happens when you block the B to D path is wrong. We have three final configurations, not two as in the above.

• From the configuration “A photon going from B to D”, with original amplitude (1 + 0i) o Amplitude of (1 + 0i) * 1 = (1 + 0i) flows to “Block with absorbed photon”.

• From the configuration “A photon going from C to D”, with original amplitude (0 + -i) o Amplitude of (0 + -i) i = (1 + 0i) flows to “A photon going from D to F” o Amplitude of (0 + -i) 1 = (0 + -i) flows to “A photon going from D to E”.

Applying the magical detector, we get a 13 probability for each of these outcomes; detector 1 detects, detector 2 detects, neither detects (block absorbs photon).

Does this work?

• I think Eliezer meant “the block absorbs the photon, and then destroys the universe”. It’s a magical block that, instead of absorbing photons, renders it impossible for them to pass it.

If it’s possible for the block to absorb the photon, then I think you got the answer wrong. Eliezer was cheating a bit with his calculations, ignoring unitarity, which was okay because everything was growing by the same constant factor. Taking into account the block, you have to start paying attention to unitarity. (See GreedyAlgorithm and [anonymous]’s comments immediately above yours.) I think this means that the half-silvered mirrors multiply by and , and hence there’s ½ probability the photon will hit the block and ¼ for each of the detectors detecting a photon.

• “So… I’m confused. You say:

″...the half-silvered mirror rule is “Multiply by 1 when the photon goes straight, and multiply by i when the photon turns at a right angle.”

We appear to have defined everything needful, except the word “when”.

Accepting that we are just performing ‘operations’ on ‘configurations’, what decides which operation will be performed? Is it the configuration of the incoming photon? Is it some magical (i.e.quantum) property of a half of a silver?” ~ Hendrik Boom

I feel the same way as above.

• My understanding is fuzzy, but the sense I get is that the word “when” just attaches to the possible configurations rather than being a condition. A rephrasing of the idea might be:

“Multiply by 1 for the configuration in which the photon goes straight, and multiply by i for the configuration in which the photon turns at a right angle.”

Which results in two configurations every time, rather than different configurations depending on what the photon does.

• ’I think the problem some of us are having is reading “They would send a photon toward the half-silvered mirror …” precludes the possibility of there being two results. I didn’t think to not picture a little (billiard) ball being propelled towards a “half-silvered mirror” and it ending up at one (and only one) of the detectors.

• So from what I understand:

A photon is merely our way of interpreting an amplitude wave in 3d-space. Such a 3d amplitude can be described by an x,y vector or (to simplify things), a x+yi complex number. (The complex number multiplied by i is really just a way of getting the same result as an x,y vector, due to the properties of complex numbers.)

Correct me if I am wrong so far, because I am about to get a bit fuzzy.

From what I see, the half-silvered mirror sends the amplitude wave in both directions, and is capable of reversing the phase of the amplitude—thus, it is possible for amplitudes to intersect and cancel out. When an amplitude gets to a detector, we can see its magnitude, and count that as ‘a certain number of photons’. This is why ‘origin of the photon’ is inconsequential (as discussed in the next article’, because a ‘photon’ is a factor of our reading the amplitudes.

That’s what I got from the article, is that a correct conclusion?

I think that I must be missing something here, because I have a few questions.

How does the half silvered mirror split the amplitude? Is the ‘wave’ split into two sub-waves with half the amplitude, and we just send ‘photons’ in bulk so it looks like ‘half of the photons’ got to one detector and ‘half’ to the other, when really each wave is split and gets to both?

Which seems like just treating photons as waves… Furthermore, as far as my understanding goes, waves are a result of particle transmission. What I’m getting at is, what is ‘causing’ these amplitudes, or how can an ‘amplitude’ be measured (and what medium is the wave measured in)?

• Hi, I’m the kind of guy I think this article was meant to target—I did not have an understanding of QM, but did start with enough base knowledge to follow the article without tripping over language or math in it.

I must say that I fried my brain trying to decipher what you’re trying to say. From one paragraph to the next, there’s a constant feeling a big hidden mental leap has been made. All of a sudden, one is left lost between notions that were introduced, but never explained.

For example. In Figure 3, from prior knowledge, I would suppose if you counted individual photons, they’d ALL end up in detectors 1 and 2 (none would be absorbed by obstacle) - this goes to explain what in fact happens when we think a particle “knows” where it’s going to end up. Please correct me if I’m wrong here.

It should also be equally possible to explain the logic behind the quantum eraser—my intuition tells me that for some reason the information that “evades” us would, given better understanding, simply be a configuration that was not possible, and it should be clear what the link between the hidden information and the way configurations work is.

• For example. In Figure 3, from prior knowledge, I would suppose if you counted individual photons, they’d ALL end up in detectors 1 and 2 (none would be absorbed by obstacle) - this goes to explain what in fact happens when we think a particle “knows” where it’s going to end up. Please correct me if I’m wrong here.

You are. If you were to put a detector 3 there instead of an absorber, it would go off half the time, and detectors 1 and 2 would each go off a quarter of the time.

• Are you implying that the presence of a detector instead of an obstacle changes what the other detectors detect, or not?

The text is unclear here:

Detector 1 goes off half the time and Detector 2 goes off half the time.

Does “half the time” mean “half the time that any detector goes off”, or “half the time you shoot a photon”? I would expect that, with the obstacle in place, half the time you shoot a photon no detector would go off, because the first mirror would deflect it into an obstacle. Seeing no detector go off is distinct and observable, so I don’t see any way it could be eliminated as a possibility like the other case described here where two possible timelines that lead to the same world interfere and cancel out. So I would assume Eliezer means “half the time that any detector goes off”. If so, I’d like to see the text updated to be more clear about this.

• It means “half the time that any detector goes off”, assuming that the block is a bog-standard lump of wood and not a magical construct like the measurement tool.

• I have a question similar to Nate’s. How does a half-silvered mirror work? More specifically, what is it about light or about half-silvered mirrors that means there are two paths for a photon out of a half-silvered mirror (compared to a full mirror, for example)? My guess at the moment is that the answer might start “light doesn’t actually travel in straight lines...”...

• You can’t explain yourself? I followed your link. It looks like part of why half-silvered mirrors “work” for the purpose of seeing someone without them seeing you is that one side is kept brightly lit while the spying side is kept dark. I think “beam-splitter” is possibly a more accurate term for my question, which I looked up and found

Another design is the use of a half-silvered mirror. This is a plate of glass with a thin coating of aluminum (usually deposited from aluminum vapor) with the thickness of the aluminum coating such that part, typically half, of light incident at a 45 degree angle is transmitted, and the remainder reflected.

(Wikipedia) Of course, this doesn’t actually explain anything—why should there be a thickness of aluminum such that part of the light is reflected while the remainder is transmitted?

Would a beam-splitter still work if the silvered and non-silvered parts were much larger (i.e. a chunky block pattern)? If you fired a single photon at that would it still make sense to calculate amplitude as you do in this post (considering the two outward paths and multiplying one by i, the other by 1)? Perhaps the distance between a silvered part and a non-silvered part needs to be close to the wavelength of the photon?

• To answer your question as to how a half-silvered mirror works, first it might be a good idea to discuss how a full mirror works.

Classically speaking, the silver in the mirror has electrons that can freely move around. The electromagnetic fields of the incoming light accelerate the charged electrons in the silver, inducing electric current.

The currents flowing in the silver create their own electric fields, which by Lenz’s law, cancel out the electric field inside the silver, and in doing so, send an oppositely-shaped wave back out into the void (the reflected wave).

Because silver is not a perfect conductor of electricity, the topmost layer of silver does not completely cancel these fields, and so the light can actually penetrate a small distance into the metal (typically nanometers) before it’s finally converted into electric current.

If the silver coating is very thin, thinner than the penetration depth, then the component of the light wave that has penetrated through the metal will escape out the other side and keep going. That is, the resistance of the thin silver is high enough that the induced current doesn’t completely cancel out the electric fields of the photon.

This classical explanation is also the same as the quantum one.

They also make beamsplitters that are like you describe—I think they call them “Polka dot beamsplitters”. I don’t remember what they’re used for. They would work the same way, but if you have a focused laser beam, the beam spot would be so small that it would either hit a full-mirrored section or a transparent section, and not both. You would need to use a lens on both sides of the beam splitter to spread the beam out to encompass the whole beamsplitter, and then gather it back. I think as long as the polka dots are not on the same scale as the wavelength, it wouldn’t cause a problem.

• If the cross-section of the photon was spread out so that it hit both silvered and non-silvered parts, some would reflect, yes. But it wouldn’t reflect quite like a mirror—diffraction effects would make things wonky, so people use half-silvered mirrors, which are nice.

How do they work, you ask? Did you ever take a course on wave mechanics where you calculated reflection and transmission coefficients? It’s exactly like that, except now the probability is essentially what’s “waving.” (if you haven’t, see here)

• Don’t know if anyone else ever comes back and reads here, but if so, I could use a bit of help.

I’m reading the quantum sequence, and I’m far enough in that the basics like this should be coming together. And mostly they are. But I have this nagging fact at the back of my mind that even though I can see why Figure 2 works, I can’t actually explain Figure 1.

I understand that the amplitude flows to both detectors. I understand that it follows the same rules each time. I understand why each end configuration gets the values it does. But why does each detector click 50% of the time?

Clearly I’m not supposed to glean that anything fundamental is happening with a 50% probability. Every path, every time, same rules. So why the apparently probabilistic result? Seems like both or neither should click every time.

• The detector clicks 50% of the time because “detector makes a clicking noise” is so complex that it doesn’t ever end up in the same state as “detector doesn’t make a clicking noise” to interfere with it. There are multiple paths this photon can take to end up in the same configuration, because the photon moving around is simple enough that we can design an experiment to make some of the amplitude that’s flowed to different configurations flow back to the same configurations – but the detector is complex enough that it separates the amplitude flows far enough that next to none of the amplitude from “detector 1 goes off” and “detector 2 goes off” will flow to the same configuration; hence they won’t (noticeably) interfere with each other. And then the human either hears or doesn’t hear the detector; the human is also complex enough that “human hears a clicking noise from detector 1” and “human hears a clicking noise from detector 2″ aren’t going to interfere; there’s no way they’re ending up in the same configuration afterwards.

Anything that remembers where the photon went will not observe interference from the photon going the other way, because it needs to be able to reach the same configuration from both of those configurations for any amplitude flow to interfere.

• I thought that was a really good, logical, simple explanation. Looking forward to reading the next episode.

Thanks!

• The post you’re replying to is from April 2008; the next part is Joint Configurations and you can follow along by selecting “Article Navigation > by author” and clicking the right arrow, or follow the whole thing in a more organised way by following the Quantum Physics Sequence.

• This is very cool. I know that’s just in my head, but now I just want a half-silvered mirror to test this with my kids.

• An xkcd take on this material

I collapsed laughing. Your results may vary.

• It’s funnny—but your brackets don’t match.

• Fixed. Thx.

• “we send some photons toward the half-silvered mirror, one at a time, and count up how many photons arrive at Detector 1 versus Detector 2 over a few thousand trials. The ratio of these values is the ratio of the squared moduli of the amplitudes. But the reason for this is not something we are going to consider yet.”

OK, but I’d still like to see a little link or something here that takes me straight to the next article where this is properly dealt with, since this seems to be the biggest gap in understanding that the current article leaves open: over and over you tell us that there are no actual probabilities involved in the phenomena at the level of the territory, yet in my quote you have exactly a probabilistic description, with multiple trials that arbitrarily yield one of the two possible results, in stark conflict with the rest of your explanation which tells us the same thing is actually happening each time (the amplitudes are always the same).

The tiniest extra hint would do a world of good here (or at the end of the article): is it that quantum impurities always stray unpredictably into our experimental setups in the real world and actually change the amplitudes involved? Or what?

• “Adjectives like probable and possible do not apply to them; they are not beliefs or sentences or possible worlds. They are not true or false but simply real.”

Based on all the “i”s in the equations I think you meant to say “complex” =p

• Is it possible in reality to fire a single photon?
(Post modified)

• after the computer program above calculates the amplitude (the same every time we run the program), can we incorporate in the program additional steps to simulate our magical measurement tool (the detector)?

• Would it be possible to actually set up this experiment at home (i.e. without an expensive physics lab)? Any particular pointers would be wonderful, even if it’s just giving a common name that this setup uses. The sequence seems wonderful, but I’d prefer not to take it on faith if I can take it on empirically-demonstrated-it-myself instead :)

start from figure 2, turn the half mirror at D round so it faces the other way, now E will light up instead of F. Since his explanation doesn’t allow for that we’ve just proved his explanation is wrong.

Anyone know if that’s right? EDIT: seems clear to me both detectors must light up if you do this. EDIT2: it turns out that by “turn around” he means through 180 degrees, which should surely mean no change.

• It turns out he was referring to this error; see How accurate is the quantum physics sequence?

• Can you clarify the question? Do you mean turning the mirror by a quarter-turn from its current orientation, so it’s diagonal in the other direction? I compute that if you do that it should work out with 14 chance of E, 14 chance of F, and 12 chance of neither (if it’s reflected back towards B or C it will never reach either). Exactly like the classical case, actually...

• Edited to clarify—I agree re quarter turn, but it turns out he means half turn. I think our thought-experiment half-silvered mirrors are unchanged by a half turn.

• 10 Sep 2011 12:35 UTC
4 points

What affects the world is real. (If things can affect the world without being “real”, it’s hard to see what the word “real” means.) Configurations and amplitude flows are causes, and they have visible effects; they are real.

Only ratios between amplitudes are “real” in that sense, because if you multiply the amplitude of everything by, say, exp(2πi/​3), nothing actually changes.
• Now, for complicated reasons that we aren’t going to go into today—considerations that belong on a higher level of organization than fundamental quantum mechanics, the same way that atoms are more complicated than quarks—there’s no simple measuring instrument that can directly tell us the exact amplitudes of each configuration. We can’t directly see the program state.

I’m not sure if you cover this in further articles… but it is worth saying:

The amplitudes of each state are not unique… there are more than one (in fact, there are infinitely many) different configurations that get you the same observable probability density, each differing by a phase factor.

• I… Er… What. Where did the whole ‘amplitude’ thing come from? I mean, it looks a lot like they are vectors in the complex plane, but why are they two dimensional? Why not three? Or one? I just don’t get the idea of what amplitude is supposed to describe.

• For that matter, amplitude of a wave...but what is waving? Where’s the realism?

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• EDIT: removed offensive statement

You didn’t finish.

• But OK, if that is how you roll, I’ll continue on to the Singularity board or Nick Bostrom’s or elsewhere and discuss the equally debunked notions of transhumanism instead. I only hope that I don’t continue to encounter the immaturity and childishness I have here.

“Skies change, not cares, for those who cross the seas.”—Horace

Good luck, if you ever finally graduate into the real world of solid objects and hard cold reality, I’ll be surprised.

If I ever turn into something you approve of unreservedly, I will be surprised too.

• botogol:

Eliezer (and Robin) this series is very interesting and all, but.… aren’t you writing this on the wrong blog?

I have the impression Eliezer writes blog entries in much the same way I read Wikipedia: Slowly working from A to B in a grandiose excess of detours… =)

• Psy-Kosh, when QM is formulated rigorously (something that is rarely done, and only by mathematical physicists) the amplitudes must be able to take on any number in the complex plane, not just the rationals.

Sebastian Hagen, I believe Eliezer is explaining to us the best model physicists have for the way the world works on the (sorta) lowest level we understand, not his personal beliefs on the nature of reality. This model must include the irrationals, to be self-consistent. This does not prevent the universe from being discretized (no uncountable sets) on a more fundamental level from QM.

• I was a little disturbed when you offered up the experiment that allowed us to reject the hypothesis about a half-mirror changing each time it reflects a photon or lets one through. How do we know there aren’t other experiments that could discredit the amplitude hypothesis? I’m sure there’s a good answer, but don’t expect me to take too much on faith.

I also thought it was odd that you called configurations real, when they just seem to be a mathematical construct that describes the behavior of photons bouncing off of mirrors. Couldn’t some other construct just as easily explain what’s going on (in an equivalent fashion)? It’s sort of like saying that y″+5y’+ y = 0 is as real as a spring bouncing up and down, when it’s actually only a model for describing what the spring is doing. Perhaps I misunderstood what you meant by “real.”

Of course these are only questions, not criticisms. This is the best explanation I’ve ever heard—please keep it up!

• Eliezer, regarding the Fig.1 experiment above you’re saying “The half-silvered mirror obeys the same rule every time.” “This same result occurs—the same amplitudes stored in the same configurations—every time you run the program (every time you do the experiment).” OK, mathematical result is the same. However, physical results at detectors 1 & 2 are not the same: click at either of them is not predictable. There is symmetry in math vs asymmetry of physical result for any individual photon. Is there any “quantum explanation” for such physical dissimilarity?

• Well, from the perspective of everyday life—way, way, way above the quantum level and a lot more complicated—the magical measuring tool is that we send some photons toward the half-silvered mirror, one at a time, and count up how many photons arrive at Detector 1 versus Detector 2 over a few thousand trials. The ratio of these values is the ratio of the squared moduli of the amplitudes.

The ratio of “photon at detector 1” and “photon at detector 2″ (averaged over enough trials) is 1.

If none of that made sense, don’t worry. It will be cleared up in future posts.

Edit: This was actually written as a response to one of these comments.

• In regards to the first experiment (Fig.1) “the little two-dimensional arrow for the configuration “Detector 1 gets a photon” has the same squared length as for “Detector 2 gets a photon”.” This mathematical equality should have resulted in each photon arriving at detectors 1 & 2 simultaneously. But this never happens. Could anybody explain to me reason for such a discrepancy between math and reality?

• In regards to the first experiment (Fig.1) “the little two-dimensional arrow for the configuration “Detector 1 gets a photon” has the same squared length as for “Detector 2 gets a photon”.” This mathematical equality should have resulted in each photon arriving at detectors 1 & 2 simultaneously. But this never happens. Could anybody explain to me reason for such a discrepancy between math and reality?

• Clarification: an amplitude is the value of a configuration?

so { a photon going from A to B = (-1 + 0i) } is a configuration and { (-1 + 0i) } is an amplitude?

• Thanks for this explanation. I’ve tried to read it some time ago but have not really coped with it. Now after reading again it was interesting for me to check if this is explained on some other internet sources and how exactly. So I checked one of the first top search results and here is what I saw: http://​​physics.stackexchange.com/​​questions/​​91695/​​double-slit-expirement-fundamentals-half-silvered-mirror-version

There some guy asked for an explanation of this experiment and answers are all about optical refraction and phase shifting, which honestly speaking would not clarify the matters for me. Now this is all ok about theory and numbers. But I tried to google some videos which will show this in action and found that actually it is not really easy (or not possible at all) to set up all these pieces and see it in action. For example, in this video https://​​www.youtube.com/​​watch?v=M6y_igUpyCg guys tries to set it up and does not succeed. Is that about he is usint a laser which in fact transmitts a bit different photons every time? Could you recommend some video where this experiment can be seen in action?

• Great post, Eliezer! I have one question, though, and maybe some of the folks here can answer it as well: why do we multiply amplitude in Figure 2 by i if it either turns “left” or “right” at 90 degrees? In the complex plane, we multiply a vector by i if we want to rotate it 90 degrees clockwise, and by -i if we want to rotate it 90 degrees counterclockwise...

So the final program state is:

Configuration “A photon going toward A”: (-1 + 0i)

Configuration “A photon going from A toward 1”: (0 + -i)

Configuration “A photon going from A toward 2”: (-1 + 0i)

Why does the bolded configuration still exist in the same way? Shouldn’t it go back to zero once the photon has reached A, since the rest of the post seems to imply a timely order of things?

• This comment refers to the editor’s note in the ebook (footnote 1). That note says that the conventional form of a half silvered mirror multiplies by −1 (not i) when a photon turns at a right angle. The note also states that Eliezer’s formulation is physically realizable, but doesn’t give further explanation. This seemed confusing to me. If a simple explanation of when Eliezer’s version is correct can be provided, then that would be helpful. My guess is that this might be when the mirror is the same from both sides: ex. if the experiment is conducted in a solid transparent medium and the aparatus is constructed by cementing together all the pieces (with the detectors also imbedded in the medium) so that both sides of the mirror have the same interface material.

• What bugs me about this article is that we have ‘half silvered mirrors’. By definition they divert half and allow half through. Like the one at ‘A’. But then suddenly, with the one at ‘D’ we get “And what D does to a photon, depends on the angle at which the photon arrives”—so not a half silvered mirror, but something else, with no explanation of how or why the angle affects the outcome.

As a layperson whose understanding changed from billiard balls to waves to probabilities I suspect there is no ‘reality’ that everything can be reduced to—and I certainly don’t think ‘amplitudes of configurations’ will be it. Even if the description is useful, they do not actually exist, just as billiard balls and the rest are just useful-at-times descriptions.

• Why doesn’t the block between B and D absorb the photon a third of the time, since it should have the same modulus as the detectors? What’s so special about things that tell us that they’ve been hit by a photon?

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• When you reply to one of my comments, the letterbox under my username lights up in red, and it won’t go away until I click on it, which links directly to the comment.

Trying to hold a discussion with you has so far proven to be fruitless as well as frustrating, and I am not going to continue engaging with you after this, but I am going to ask you to stop coming back to this conversation over and over with new comments, because it is going to cause annoyance whether I reply to them or not.

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• Could you answer the question with a yes or no? That’s really all that it takes.

• Not a yes, or no question D. (Like‴Have you stopped beating your wife). We don’t test a hypothesis. It is an assumption or assumptions that we accept or not based upon it’s rationality.

• I think we are extremely unlikely to make any headway here. In fact, I have thought that for some time now, and I really should have resisted the temptation to reply to you any more at all.

Since you have consistently demonstrated a failure to actually stop posting when you say you will, I am making a precommitment not to respond to any more of your comments, unless you can answer this question for me. If you reply to this comment without answering the question, I will no longer respond, and if you give an answer I do not think actually addresses the question, I will not respond.

How and why do you think doing science the way you propose will lead to better results, given that throughout history, when people did not refine their models through testing, but judged explanations only by their “rationality,” they were overwhelmingly wrong?

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• BUT MORE IMPORTANTLY, WHAT DO YOU WANT?

Get a blog and stop commenting here.

• Eliezer is saying that when the ratio of the squared moduli is 1, than Detector 1 goes off half the time and Detector 2 goes off half the time. But why it should be necessarily interpreted this way? Is this another QM rule? What prevents, in this case, an alternative interpretation: a photon must split in half and arrive at both detectors at the same time?

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• This is true but irrelevant because the site you are citing contrasts general relativity to Newtonian physics, not the model Miles Mathis is claiming which issues completely different predictions.

Please stop trying to continue this conversation.

• Please stop trying to continue this conversation.

The way to make that happen is by NOT responding to their comments. Only downvote, don’t reply. Also, downvote those who reply, irrespective of how well their comments are composed, to discourage the behavior that encourages bad conversations (the conversation that sprang from your reply is currently 30 comments strong).

• I regret that now, but Monkeymind has kept coming back to comment now repeatedly since I previously stopped replying to his comments, and I was hoping that negative feedback would deter him where an absence of feedback had failed to.

• This is true

The linked site (http://​​www.physicsmyths.org.uk/​​) is a crackpot site which argues that special and general relativity are wrong. So (given what I have heard from credible authorities about the workings of GPS’s) I would actually bet that the claim is false.

• I only briefly eyeballed the site, and didn’t have that much awareness of the content. I am aware that GPSes incorporate the predictions of General Relativity for their calibration, but it did not strike me as implausible that the deviations from Newtonian physics would be within their error margins, at least up to this time of operation. I admit that I was very much premature in asserting that it was true without doing the calculations myself. Thanks for pointing that out.

• I wish EY would come straighten you guys out!

I’m hesitant to point this out after saying I wasn’t going to engage with him anymore, but this sounds way less like something someone who’s sincerely spent months chasing after the idea that Eliezer is seriously misguided for what he wrote in Configurations and Amplitudes would say than someone who was deliberately trying to crank the levers of other readers. I’ve wavered previously on whether to give him the benefit of the doubt, but at this point I think it’s only fair to assume that Monkeymind is a troll rather than a hopelessly confused person.

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• I’ve spent a while hanging around conspiracy theorists online, and taken the time to follow up on the sorts of people who get talked about for proposing “revolutionary” theories which are kept down by the scientific orthodoxy.

What distinguishes people in this category, of which Miles Mathis is typical, is not failure to produce testable hypotheses, but the production of hypotheses that are trivially wrong. If Miles Mathis’ claims about physics were correct, to point out a single instance of failure, GPS satellites, rather than being geosynchronous, would crash into the earth. The math he uses in his models is simply wrong (RichardKennaway already linked to a site which does an accessible rundown of his errors.) Trying to use him as an example of a mathematician whose work refutes quantum mechanics is no different than trying to refute relativity by citing a person who uses incorrect mathematics to outline a model that implies that the world is flat. Even if quantum mechanics or relativity were incorrect, these arguments would be completely meaningless.

Here’s a starting point that might, just possibly, help us actually get somewhere. Do you agree that if a hypothesis is correct, it shouldn’t predict things that aren’t true? For instance, if a hypothesis indicates that the world is flat, and you can fall off of it, and experiments show that you can travel in a line around the world and end up where you started, then the hypothesis indicating a flat earth is wrong?

• What are you calling rationality in this statement?: A community blog devoted to refining the art of human rationality

See this post or this wiki entry.

In short, we mean either epistemic rationality or instrumental rationality. Epistemic rationality is the art of having beliefs that correspond with reality. Instrumental rationality is the art of taking actions that further your goals.

• x

• If I may jump in here… You can get from common-sense physical concepts to quantum physics in a finite number of steps, but the resulting construct almost certainly does not satisfy your criteria for being a theory. Roughly speaking, you can start with a few common-sense concepts like object, motion, mass, force, then proceed to their mathematical incarnation in Newton’s laws and Maxwell’s field equations. At this point you have classical physics, which offers a framework for talking about point particles with mass and charge, and force fields which pervade space and are described by a vector at every point in space, interacting according to some law. Then, when you proceed to quantum mechanics, you describe the particles and fields, not by saying exactly where the particle is or exactly where the field vectors are pointing, but rather by using probabilities for all the distinct classical possibilities. But you don’t even use ordinary probability functions; instead, each possibility has a complex number attached—basically, a two-dimensional vector, and then the probability is the square of the length of the vector.

As you may have surmised, these layered concepts are now several steps removed from a physics which offers exact, deterministic descriptions of recognizably physical objects. However, there isn’t a complete disconnection. At the bottom you’re still talking about objects and forces acting on them. You still have conservation of energy, straight-line motion unless a force acts, etc. The description is fuzzy and the predictions are just probabilities, but even the peculiar framework of complex numbers is just a slight modification of the mathematics of motion and interaction appearing in the classical theory.

By your conceptual standards, this is indeed not a theory. It’s a hybrid of sensible concepts (the classical picture) and mathematical rules (the quantum mathematics). The result does not provide a clear picture of reality and yet the physical concepts are indispensible in grounding the mathematics anyway. Hundreds of physicists across the decades have tried to restore clarity to physics by producing a deeper theory, but the mainstream has mostly adapted itself to simply working within the hybrid framework. This sequence of posts is about a radical attempt to make sense of the probabilities by saying that there are parallel universes; all possibilities are actual, existing alongside each other in some ultimate hyperspace. However, the complex numbers are still left over, unexplained, but attached to each parallel universe. The parallel universes are the “configurations” and the attached complex numbers are the “amplitudes”. So it’s still a hybrid construct in which the conceptual physical picture comes with some unintegrated mathematics that’s just tacked on… Beyond this point, you can (1) retain the multiverse concept but keep looking for a version which makes more sense (2) tell yourself that amplitudes-attached-to-configurations is just how reality is and you need to adapt your standards to this (3) look for an entirely different explanation.

• x

• I did mean you, specifically. Learning QM has been compared to learning to ride a bicycle. You don’t do that by first defining your terms, you just get out there and do it, and it’s hard to reduce the knowledge of how to ride a bike to definitions. When people learn QM, they slide past some difficulties of logic, and are “rewarded” with the ability to quantitatively describe and predict atomic behavior.

There is a huge spectrum of attitudes among physicists towards the logical or conceptual basis of QM. On this site, they want to make sense of QM by adopting a radical new picture of reality in which there are “flows” of “amplitude-stuff” through the hyperspace of parallel universes. This is a genuine faction of opinion among physicists. But then you have the more down-to-earth people who tell you that quantum physics is just like classical physics, except that everything is a little “fuzzy” or “uncertain”. This view is something of a philosophical placebo which allows its adherents to feel that there is no conceptual problem in QM.

Regarding even more basic matters, like what’s going on in the very first steps towards the mathematization of physical concepts, that is a discussion that interests me, but we would first need to agree on exactly what the “issues” are, which might take a while. So I think we should have it privately, and then report back to the site, rather than flailing around in public. My mail is mporter at gmail.com, please contact me there if you want to continue this dialogue.

• Learning QM has been compared to learning to ride a bicycle. You don’t do that by first defining your terms, you just get out there and do it, and it’s hard to reduce the knowledge of how to ride a bike to definitions.

This may indeed be the case, but taking the outside view—if I didn’t know you were talking about QM, but knew it was about some purported scientific theory—giving a free pass to the usual strict rationalist requirement to “define your terms clearly” would seem pretty dubious. There are a lot of ways to build whole systems out of equivocations and other such semantic fudging, a lot of religious argument operates that way, and so on.

• However, if I can’t get past the conceptual stage, all the numbers in the world are meaningless to me.

Probably best to avoid QM for now then. It’s at a deep enough level that effectively, the meaning is the math (see this XKCD).

If folks think science has anything to do with belief

I’m not sure what you mean by that. A belief is a human’s internal representation of a part of the world. Science is about the world and is done by humans, so beliefs are involved. If you were to do science without brains, you might be able to avoid belief, but I wouldn’t bet on it—our best AI also uses structures analogous to belief (but more formally rigorous than your typical human’s) to model the world.

• x

• I can relate to objects, but I can’t relate to abstract concepts.

Sounds like you think very literally or visually. Reminds me of Michael Faraday, one of the discoverers of magnetism, who is said to have known very little math, only basic algebra, but who invented the electric motor through experiment and his ability to understand concepts visually (with no math!) It’s a different type of mind, that’s all, and quite practical. I like math and find it moderately easy, but I would never be able to figure out how to make electronic circuits by playing around with them.

What is math? Well, you have three apples and you have three skyscrapers and you have three mouse droppings...what do they all have in common? Not that materials they’re made of, but the fact that there are three of them. When you think the number ‘three’, you can imagine three of any object. It’s not limited to you being able to imagine three of your fingers...I could tell you any noun right now and you could imagine three of them.

• Thank you, yes, I can understand nouns. You point at something and give it a name. I can understand three. I can’t understand how ‘three’ can travel. Because there is no such thing as ‘a’ three. I can also not understand how a three can travel in a non specific direction. I can understand how three apples can travel on a truck or through the air if I throw them. I can conceptualize these things quite easy. I can understand the 3 dimensions of LWH. I can visualize all kinds of 3 dimensional shapes. I can not visualize 4 dimensions and according to Steven Hawking, no one can.

Although I can plot a sine wave on a graph or observe it on an o-scope, I can see that these things are representative of something that is happening....an event. I can not visualize a ‘wave’. I can visualize someone waving their hand in the air. I understand a wave is a disturbance through a medium. The hand disturbs air molecules. The wave does not travel the hand does.

We use math to describe waves and energy and fields. When theories use these words interchangeably as nouns and verbs, I realize that it is not only grammatically incorrect at times, it is nonsensical and so I must disregard what I am being told.

• A word can be a noun and a verb. You can warm your feet at a fire, or fire a gun, for instance. The informational content is what’s important, not the words themselves.

Sometimes, difficult to understand jargon conceals actual nonsense, but sometimes it’s simply a way for people who’re well versed in a subject to communicate with each other efficiently. As a rule of thumb, if people are able to successfully predict things in advance which you can’t predict, or make things you can’t make, then you should assume that they really do know something you don’t.

• Nouns and verbs can not be used interchangeably. You can warm your gun but you can’t fire your feet. Love doesn’t move mountains and one can not carry a force.

If we are chatting like two good ole boys then fine, we don’t necessarily have to define terms. If you are making a hypothesis, then you had better define your KEY TERMS. To be used scientifically words must be precise, unambiguous and non-contradictory.

Science describes what has already happened. I can predict the sun will come up tomorrow, but if the sun supernovas and disintegrates the earth...well so much for my prediction.

• Scientists do define their terms, much more precisely than we generally do in ordinary conversation. When scientists say matter has both wavelike and particlelike properties, they have a meaning so precise they can write it into a computer program. The issue here is not that their terms are faulty, it’s that you don’t understand what they mean.

• Taking the outside view—that is, forgetting this is a conversation about QM—this sounds a little hand-wavy. It seems natural to ask for precise definitions of basic terms in an article about QM, and for consistency in their usage.

• I can’t draw an electron. In fact, nobody can really draw any sort of fundamental particle. They don’t look like anything. This might seem like a cop out, or a way to handwave away the fact that we don’t know what they look like, but it’s not. On the scale that fundamental particles exist on, the mechanisms which give rise to the phenomenon we experience as “looking like something” don’t exist. An electron cannot look like anything.

I can understand something and still tell you that it makes no sense. Do you understand that? I can also regurgitate the definition of phase angles that I memorized in 1978, does that mean I understand it?

If you insist that you understand what scientists mean when they call matter wavelike and particlelike, why don’t you try explaining it? That much, I do understand, well enough that I can explain what it means I should observe regarding matter on the particle scale and what I should not, and I will be able to tell if your explanation is correct.

I also can’t explain directionless arrows, because to the best of my understanding, Eliezer isn’t actually talking about directionless arrows at any point. If he is, my understanding of this post is wrong. What he does talk about are arrows, figurative entities which indicate both what direction from the origin something is pointing and how far away from it is is (I’m not even going to try explaining what the origin in this context is and what it means to move away from it, not because I don’t understand it, but because it would take way more time and effort than I’m willing to put in right now to make it comprehensible to you,) but although the arrows point in a specific direction, we can’t tell which direction it is. Imagine an actual, physical arrow affixed to a pole in the ground, and the arrow is pointing either north or south. Imagine also that we have no way of knowing which way is north or south, we have no compass, the sky is overcast, we have no landmarks to orient by, etcetera. We do not know whether the arrow is pointing north or south, but we can still measure how long it is.

This is not a perfect analogy, but if you think of it this way you’ll have a better idea of what Eliezer was talking about if you just think “directionless arrows = nonsense.”

• x

• Actually, I already explained wave earlier. “A disturbance thru a medium” is the best definition which can be used consistently. Of course we could refer to the popular definition, from WIKI or whatever. But you asked me my definition. A particle is a discrete “piece” of matter, or in the case of a photon, a discrete ‘amount’ of energy, or quanta.

“A disturbance through a medium” is not what scientists mean when they say that matter has wavelike properties though. It doesn’t matter what “your definition” is, if it’s not what scientists mean when they use the phrase “matter has both wavelike and particlelike properties” to communicate an idea to each other.

In any case, I’ve been suspicious for a while, but at this point I think it’s very likely that you’re deliberately trolling this site. You’re combining a significant level of familiarity with scientific anecdotes with a profound, seemingly willful level of ignorance, and I think you’re faking it.

• Reminds me a bit of this.

• No, not exactly like that, as I just explained in my last post. However, I have some paradigms that have allowed me to successfully cut through a lot of BS. If I discover they do not apply to mathematical physics, then I won’t waste any more of your or my time, that you can “count” on.

• x

• No, you’re not making too much sense for someone who’s profoundly ignorant, you’re making too little sense for someone who knows what you seem to know. It’s possible that you’ve actually gone out of your way to pick up all these words and pass phrases without having any idea what they mean, and that’s exactly what you’re acting like, but I don’t buy it.

I don’t want to continue a discussion with you if I think you’re willfully refusing to understand, but I like this analogy, so I’m going to toss it out and if by some chance you’re not faking and it actually helps, it’ll give us something to work with.

A person who is born blind and grows up that way does not have the neurological faculties to process an image and take information from it the way we do. A blind person may have a concept of “sphere” or “cube,” and know what they will feel if they run their hands over one, but if a person who’d grown up blind were given functional eyes and looked at a sphere, they would not be able to tell you in advance that by running their hands over it they should feel a smooth surface that curves uniformly in on itself. This was an issue which was debated for some time by philosophers, but eventually we developed the medical technology to actually give eyesight to some people who’d grown up without it, and it stopped being just a matter of “logical argument,” and became something we could go out and actually check.

If you were to take a person who’d grown up blind, and try to explain the concept of looking like things to them, it would be incomprehensible to them. Generally, blind people take it for granted that sight is a real phenomenon that they’re missing out on, because civilization around them runs on it in such a way that it wouldn’t make much sense if all the sighted people were just making it up. You could describe the mechanics of sight to a blind person, but they will not be able to conceive of the idea of “getting a picture in your head” the way we do. If a blind person told you “Don’t mess around with math and diagrams (which I can’t see anyway, so fuck you,) just give me an explanation of this whole “picture in your head” thing which you say lets you tell what shape something is without touching it,” no matter how you explained it, you wouldn’t be able to get them to understand sight like we do. It’s not that there’s something wrong with our models of how sight works, the problem is in the brain of the person who’s never developed a capacity to deal with vision.

Similarly, our brains don’t have the capacity to picture what’s going on on the scale of fundamental particles. There’s no reason why they should. Like blind people dealing with sight, we can explain what’s actually going on, but it’s never going to make intuitive sense to us. Can’t visualize a zero dimensional particle? Well, who says fundamental particles have to have size? Who says there can’t be any real thing which doesn’t take up space, so you can pack any number of them together without ever getting a bunch an inch across? Who says that you can’t really tell what shape something is until you run your hands over it?

If a blind person, unable to comprehend sight, decides that sight doesn’t exist, there will be things in the world around them that just don’t make sense to them. Similarly, there are physical theories which we can’t picture, but we can tell that the world around us makes a lot more sense if they’re true than if they’re not.

• Your method of argumentation is a little unusual and perhaps a bit off-putting, but I don’t know why all your posts are being systematically downvoted this low. It’s clear from posts like this one that you’re not merely trolling, but I think you’re taking on too much at once. Also, your style is not very LessWrong friendly and you’re posting a lot. Maybe slow it down a bit, get familiar with the lay of the land a bit more.

I, for one, would like to hear a bit more about your misgivings. You’ve said some interesting things so far that have got me thinking.

• As he comments, his posts show a clear disagreement with the scientific method. That, not the truth of quantum mechanics, is a basic part of what this community calls rationality.

Later in this sequence, Eliezer asserts that QM represents a failure of science to be as rational as it could be. The example can’t be understood unless one has a fairly good grasp of QM, but the truth of QM is not precisely the point of this particular series of essays.

(As an aside, I’m not completely convinced of the point because I think the example is poor, but that also is unrelated to the truth of quantum mechanics).

• Further, explain a zero dimensional particle without math or magic.

Descriptions of anything to do with ‘zero’ contain math, either explicitly or implicitly. Demanding that others explain mathematical things without using math is a highly dubious tactic and I’m not sure what it is supposed to achieve.

• My bad, I meant no dimension. 0 is for counting. Numbers can do anything apparently. Words can not. Mathematicians say they understand each other and perhaps they do. Perhaps I just can’t use EY’s magic tool yet?

• One can’t really “explain” a particle. I would say, however, that if you cannot show the shape of the particle (how it occupies space), it is somewhat questionable to call it a “particle” in any classical sense that I’m familiar with.

• I don’t think anyone disputes that the classical definition of particle and wave don’t really apply in the quantum mechanics level. But QM makes good predictions. If QM talked about the blicket/​fand distinction, and said that blicket was sort of like particle, and fand was sort of like wave, would you be more comfortable with it?

Because QM is the only scientific theory that explains observations, including the weird ones. That’s something that needs to be acknowledged. The idea that math can’t be used to describe reality is just a more specific way of saying that we can’t describe reality at all.

• Can you draw a dimensionless particle for me please?

All drawings that we do are abstractions. They represent something from a reality (fictional or allegedly actual) but they are never the same as the actual thing—they just represent it. Mathematics does much the same thing—just better.

• OK, then draw a dimensionless point for me. If you can’t do that then describe it.

• I plus thee for humor! That’s what I thot. Now how many of these makes up a one inch line?

• Depends how far apart you space them. In a black hole, you could crunch up all the particles in existence into the same space, and you still wouldn’t be any closer to spanning the length of an inch.

We might not be able to visualize this, but our brains developed to help us operate on a scale where things actually do behave as if they were all made of substantial lumps of stuff which take up space and two things can’t be in the same space because the space is filled. That’s the sort of thing our brains evolved to deal with, so whether or not reality really works like that at the most fundamental level, we should expect ourselves to be bad at envisioning things that don’t work like that. For a rather long time, scientists thought that reality was like that all the way down. But then when we developed the technology to do experiments which actually probe what’s going on at that level, we started finding that reality simply doesn’t work that way. You can try and envision matter as being made of tiny little lumps of stuff bopping around, but if you do, you will unavoidably end up drawing conclusions that contradict what we find is actually going on.

“I can’t get a picture of this in my head” is not a rebuttal of a physical theory, because there’s no reason that our heads must actually be equipped to create pictures of how the fundamental level of reality works.

• “I can’t get a picture of this in my head” is not a rebuttal of a physical theory, because there’s no reason that our heads must actually be equipped to create pictures of how the fundamental level of reality works.

Agreed, the basic structure of reality may be unvisualizable and otherwise incomprehensible to us. However, a theory is ostensibly a physical explanation, not merely a mathematical summary of the observed data. Reading over Monkeymind’s posts, it seems the point he is making is that these theories sort of seem to “feel like” physical explanations, but in the end are “just math.”

The question naturally arises, to the newbie at least, of what the difference really is between a mathematical summary of the data we’ve collected and a mathematical theory of how (by what mechanism) a physical phenomenon occurs.

• x

• I can’t explain QM very well, but here’s a video of “someone that can”. I would recommend paying special attention to the speech he gives around 37:00 minutes in about concepts like “wave” and “particle”, which we have coined in the macroscopic world and how we should not really apply terms which have mutually exclusive qualities in the macroscopic world to describe the world of fundamental particles.

His answers might still be unsatisfactory to you, but its the best I can offer.

• Yes, “we should not really apply mutually exclusive terms.” And thank you for using the word concept when relating to wave and particle. I think the whole issue is knowing the dif between concepts and objects. Physics should be about objects. Of course all words are concepts, but if they can not resolve down to objects, they should not be used in ones hypothesis or theory.

Thanx for the link, hopefully I will be able to get to it.

• Physics should be about objects.

My high-school physics class spent a lot of time talking about distances, and time, and forces, and velocity, and accelerations, and vectors. Neither distance, time, force, acceleration, velocity, nor vectors are objects; they are concepts we’ve formulated to characterize particular patterns in the ways objects behave. They sure seemed useful to me. So I’m inclined to reject this claim.

• Why shouldn’t physics talk about concepts? Or first, what is your definition of “object” and “concept”—even just by examples.

• Just because we can’t visualize something doesn’t mean we can’t work out the rules. If quantum mechanical models accurately describe what’s happening, the fact that we can’t picture it in our heads is not a problem.

I would be a lot more willing to help you understand if I didn’t think you’re being obtuse on purpose though.

• If quantum mechanical models accurately describe what’s happening, the fact that we can’t picture it in our heads is not a problem.

I think there’s a danger of equivocating here on the words “what’s happening.” In other words, which “what’s happening” do the QM models describe?

I’ll elaborate. If we observe X, do the QM models describe X, or do they describe the (so far unobserved) phenomena that may underly X?

• If the mathematical QM model merely describes X, it’s hard to see how it is anything other than a very succinct cataloging of the observations, put in a very useful form. That’s quite an achievement, but I can understand the hesitation with calling it an explanation or a theory.

• If the QM model actually describes some as-yet unobserved phenomena that is proposed to underly X, then it seems like it avoids Monkeymind’s criticisms because there is actually something additional being posited to be happening, behind the scenes as it were.

If it is the latter, I’d be interested in seeing an example (anything in QM).

• If the QM model actually describes some as-yet unobserved phenomena that is proposed to underly X, then it seems like it avoids Monkeymind’s criticisms because there is actually something additional being posited to be happening, behind the scenes as it were.

There are probably more examples than I’m aware of, but as I pointed out in an earlier comment to Monkeymind, quantum entanglement, which was regarded as an extremely counterintuitive prediction, was predicted by quantum mechanical models well in advance of observation.

ETA: Bose-Einstein condensates also come to mind.

• If QM were false, computer circuits would not work.

• That depends how false, and in what ways.

• Yes, but I’m a lawyer and lack the background to give a more specific example. All I’m trying to say is that disbelieving QM does have practical, real-world consequences.

• Well, I agree that there are things about the scientific process that could be done better, and I think most of the other people here would also, but I expect we disagree about the specifics. Can you tell me what you think ought to be done differently and why you think it would work better?

• x

• That’s an extremely unclear explanation.

I think it would be easier to understand if you were to frame it in terms of specific examples. Supposing you want to find something out, how would you expect a scientist to do it, and how would you do it differently? Try using an example with a specific question, like “what makes it rain?” or, if you want to exercise some more creativity, something that we can’t easily look up the answers to, like “if you put someone in a position of power, do they really become more inclined to take advantage of people, or is it just a difference of opportunity?”

At this point, I don’t think we can work through this article without hashing out our differences about the scientific method. There’s too much of a gap of inferential distance (and please actually read that post I’m linking to, I’m not just putting it there for thematic appropriateness.)

• x

• This makes good sense and is the very reason why it is crucial to define ones KEY TERMS in the hypothesis stage. It is why I press for precise definitions, only to be told I do not understand or I am being obtuse, etc. I have been told that scientists use precise terms, but wave, particle, energy are anything but. It seems that they are having difficulty telling the difference between nouns and verbs as has already been discussed. Let us stick with WAVE for now:

Give me EY’s definition of wave (as pertains to this article). I gave mine earlier and was told it was not the scientific one as relating to the particle/​wave duality. If wave is a disturbance through a medium, then wave is not an it but a what. This whole wave/​particle paradox might have been avoided had someone defined the terms waaaay back then.

Scientists did define their terms way back then. They never introduced the idea of a wave/​particle duality without knowing exactly what they meant.

The reason I keep diverting from the topic is that it takes more than just defining one’s terms to communicate complex ideas without a shared body of information. Try and explain evolution to a person who’s been brought up in a fundamentalist household, for instance, and while you might pat yourself on the back afterwards for an explanation well delivered, they’re probably not going to come away understanding it, unless you take the time to bridge the entire gap of uncomprehension.

I seriously suggest reading the Mysterious Answers to Mysterious Questions sequence, which I linked to before, because some of the points you’re expressing are misconceptions that it was written for the specific purpose of addressing. Eliezer wrote the sequence in order to bring people up to the point of being able to meaningfully discuss the ideas we work with here without talking past each other. He put a lot of work into them, and I’d rather not replicate it all when it’s already there for exactly that reason. There is a reason that Mysterious Answers to Mysterious Questions is the first in the suggested reading order of the sequences, and the quantum physics sequence is the fifth.

• x

• Yes, it does take far more than just defining ones terms, but we must start there b4 we can go anywhere else! I don’t mean a infinite number of now define that, now define that....just the KEY TERMS of one’s hypothesis b4 moving on to the theory. Whatever the defs are they must be used CONSISTENTLY.

I agree that key terms need a definition. They have apparently all been defined before, but no one here has yet shown an interest in giving those (or any) precise definitions right now. I’m not sure why, especially given that this is LessWrong. I’d help you out on that, but I honestly don’t know the precise definition that QM theorists use for wave. Surely someone must know?

• What wrong answers do you see it giving?

• While there are plenty of issues affecting reproducibility of scientific results, physics is much better in this area than other sciences having stricter requirements to establish statistical significance.

• I plus thee for humor! That’s what I thot. Now how many of these makes up a one inch line?

How big is an “inch” again? I’m stuck in the 21st century over here. We haven’t used inches since before my parents were born.

More seriously, why would I try to make up a one inch line out of dimensionless points? That sounds difficult and doesn’t seem to prove anything.

• x

• When theories use these words interchangeably as nouns and verbs, I realize that it is not only grammatically incorrect at times, it is nonsensical and so I must disregard what I am being told.

I’ve read in a lot of books on quantum physics that yeah, the ways of explaining it with commonplace nouns and verbs don’t make sense. But the math makes predictions anyway, so we can make a wild guess that whatever reality is like on that level, it has something that corresponds to our mathematical concepts. There are ‘particles’ which are a little bit like our everyday conception of the word (a small piece of matter) and a little bit not, since no commonplace ‘particle’ is massless. But the math only gives correct predictions if you have some particles, like photons, be massless...and it’s simpler to assume that they actually exist than that we’re getting the whole theory horribly wrong and somehow still getting useful predictions out of it.

• OK, now we are getting somewhere. Predictions and wild guesses! QM only makes correct predictions if one invents massless particles like photons. The LHC will never discover a massless particle no matter how many billions of dollars are poured into it. Marge Simpson was right!

• The fact that QM says things about reality that you don’t like doesn’t change the fact that QM makes correct predictions. Many commenters in this thread have pointed out that there is a mountain of experimental evidence in favor of QM and against “intuitive” theories of physics. You have essentially ignored that body of evidence and insisted that reality must be simple, intuitive, and easy to explain. At this point, I have to ask: How much evidence would it take to convince you that our universe’s physics are complicated? What observation would you need to see for you to believe that reality isn’t always intuitive and easy to understand?

• x

• It is not about weather or not I like that QM makes “correct predictions” because reality is not about ’predictions.” Is it up for vote? It is not about mountains of experimental evidence in favor of QM., because evidence is opinion based on fallible human observations (5 senses). Nature does not ask for anyone’s opinion.

Tell me something: Is “Monkeymind” intended to be an avatar account, along the lines of “Clippy”. If so you have absolutely nailed it. You have role played the mind of the human mind (with its monkey-kinship) as it grapples with understanding physics at a level that is beyond its usual scope of practical optimisation and you have done so perfectly. I just can’t tell whether you meant it that way or not.

• Yes, and you are not answering any questions I put forth further illustrating monkeyminds at work here. Care to show me where I don’t understand physics. I can argue that you do not. In general because physics should be abut objects that exist and in particular because you can not give me a hypothesis of what object mediates the phenomena of light, let alone a theory which explains your hypothesis. All you seem to be capable of doing is be condescending.

• Tell me something: Is “Monkeymind” intended to be an avatar account, along the lines of “Clippy”.

Yes

That being the case trying to argue you into not thinking like the monkeymind avatar in question would be equivalent to trying to convince Clippy that paperclips really aren’t all they are cracked up to be—pointless. If you admit (as you do above) that your account is a satirical role-play account rather than you sincerely expressing your ignorance then you shouldn’t expect people to be obliged to buy into your games. Feel free to retract the ‘yes’ at any time if you wish to be taken seriously.

All you seem to be capable of doing is be condescending.

If you role play an avatar that is bad at thinking it is inevitable that it will seem to you like people are treating you as if you are stupid.

• Sorry, I did not understand what you meant by Clippy. Never heard of it b4, so I answered hastily. I use Monkeymind everywhere. I used this avatar originally when discussing evolution with theists, and just kept the name.

I am being serious, and so obviously my questions are serious, and they must be good ones because so far, there have been few reasonable answers. One may say that it is because I truly do not understand the topic(s). Feel free to set me straight any time, rather than just telling me I don’t understand.

If you would like to show me where my ignorance lies or that my thinking is flawed, I would appreciate it. I don’t like being wrong, but I don’t mind being corrected. In fact, I desire it so that I do not have to continue holding on to outdated or non-useful explanations.

However, let me state that I do not necessarily think there is a wrong or a right conclusion to the scientific method. Just explanations which are rational or not rational. Explanations that make sense or do not make sense. If this is the flaw in my thinking you are alluding to, then feel free to make a case for that. If it is about the thot experiment of computer generated amplitudes being fired at make believe half-silvered mirrors, then I am all ears.

Theoretical physics is conceptual. Technology (mostly trial & error) is empirical.

Maybe in the process, I will learn something and I can help you realize the limitations of math and the current state of your (apparently collective) understanding and use of the scientific method.

• Sorry, I did not understand what you meant by Clippy. Never heard of it b4, so I answered hastily.

Thankyou. Your outrage didn’t seem to fit with your affirmation so I thought I’d give you a chance to re-answer.

• It is not about weather or not I like that QM makes “correct predictions” because reality is not about ’predictions.”

I strongly recommend that you find a physicist and say this to them. They will almost certainly disagree, because making successful predictions is what science is all about. Theories explain, yes, but they do so by offering a mechanism or creating a model for how something works, and the only way to tell if that model is correct is by seeing if it can accurately predict reality. To invent an accurate post hoc explanation if you need the ability to test its validity, and the only way to do that is to see what advance predictions it makes and test those. This is, of course, the reason scientists perform experiments.

The rule based language of math only describes, it has no explanatory value at all!

Again, I strongly recommend you speak to a physicist about this, because it just isn’t true. In the meantime, take a look at this LW post, which is a clear example of how a mathematical theory of physics, in this case Newtonian physics, can make predictions.

Give me a hypothesis of what object mediates the phenomena of light and then your theory can explain refraction, reflection, diffraction, dble slit and half silver mirror experiments.

This is my hypothesis. The things it deals with aren’t “objects” in the way the word “objects” is usually used, because the term generally refers to things made up of more than one atom, and QM describes things at a much lower level. However, QM does helpfully provide precise mathematical rules for how these sub-atomic things behave, some of which are outlined in the original post. We know that this explanation is true, at least to a certain degree of approximation, because of its experimental success at predicting some of the things you listed (double slit experiments, etc.). You can talk all you want about how much this doesn’t “make sense,” but the fact remains, the mathematical model outlined in QM is extremely good at predicting reality, which strongly suggests that it really does describe what’s really true.

• Um, and what’s your point?

• The point is QM has to invent non-existent massless particles to make their math come out. Nature could care less about mathematical constructs or models.

And BTW, speaking of point, can you define point for me? Everyone here seems to want to tell me what I don’t understand. Perhaps you can educate me.

• I’m actually not sure if you want me to define ‘point’ as in ‘zero-dimensional particle’ or point as in ‘what do you mean.’

Nature could care less about mathematical constructs or models.

Nature could care less about whether you can intuitively understand it, too.

• Eliezer can tell us how to visualize triangular lightbulbs, but not zero-dimensional objects. Which is more mysterious?

• Reality is about what is real. Objects are real. They are made of matter (atoms) they have shape and location. Amplitudes, configurations,laws and flow are not real. They are not objects they are what objects do.

I understand why you think so, since your species evolved with sensors that work at a particular macro level, and so intuitively you expect everything in reality to work the same way. It does not make sense to you that the same rules don’t apply if you go really really fast, or if you’re looking at something really really big or really really tiny, or if you’re observing a process over a very short or very long time scale.

Sadly, this is a design flaw in your brain. You will not likely be able to rework your intuitions so that reality always “makes sense”. Reality doesn’t have to conform to your preconceptions, and your brain just isn’t made to radically transform itself like that.

Luckily, you can choose to use a mechanism other than human intuition to understand the universe. Like mathematics, which seems to do a much better job, even in a way observable to humans. We have lots of devices (observable at human scales!) that do exactly what the mathematics said they would, like GPS.

But despair not! It’s not completely a lost cause. Even though we are not made to understand things directly using math all the time, there are ways of retraining your intuitions to some extent, and correcting for your design flaws in other ways where that’s not possible. Figuring out how to do that is the primary mission of this site.

• Luckily, you can choose to use a mechanism other than human intuition to understand the universe. Like mathematics, which seems to do a much better job, even in a way observable to humans. We have lots of devices (observable at human scales!) that do exactly what the mathematics said they would, like GPS.

I think there is a common miscommunication on this point. If something cannot be understood in the conventional human sense, can it be understood via math? It depends on what we mean by “understand.” We can certainly catalog what we observe and summarize those data in the form of mathematical formulae and models.

However, if those are merely very succinct summaries, it is no surprise that they make accurate predictions, as they would effectively just be extrapolating from the observed data. It also seems unsatisfying to call that a theory in the traditional sense, if it is really more like curve-fitting.

• Einstein said one should be able to explain any theory to a barmaid and Feynman said if you can’t explain it to a 6 year old then you don’t understand it.

Both of them were pretty good at explaining things, as scientists went, but this is a serious exaggeration as far as the actual comprehensibility of the theories goes. The six most accessible chapters from the Feynman Lectures on Physics, republished separately as Six Easy Pieces, are still way over the head of an ordinary six year old, and the Theory of Relativity was famously little understood in its time. I recall reading one anecdote by a contemporary where he says that he spent several days with Einstein, and every day Einstein tried to explain the theory to him. He said that by the end of it, he still couldn’t make head or tails of it but was convinced Einstein knew what he was talking about.

Some theories in physics today are genuinely very difficult to understand, and take a lot of focused study to make sense of. I was accounted a pretty promising student in physics, and dropped the subject after a year in college, and a lot of stuff was still way over my head by the time I switched tracks. But the reason they actually believe these theories, and consider them theories rather than simply conjectures, is that they’re very well supported by evidence. They’re unintuitive and hard to understand, but it appears that they’re actually true regardless.

Human beings never faced evolutionary selection pressure towards being able to understand the most fundamental workings of reality. There’s no particular reason they should be easy for us to understand.

• It was never “true” that the earth was flat. Obviously the earth was round before people figured out that it was round, but there were no experiments which “confirmed” that the earth was flat. The earth was demonstrated to be round by experiment in the third century BC, and we have no evidence of any experiments predating that which indicated otherwise. The roundness of the earth was not discovered by the “common sense” of ships vanishing over the horizon.

Experiments showed that the earth was round, to within a small margin of error. Further discoveries showed that, within that margin of error, it was not perfectly round. At each step, experiments advanced our knowledge, rather than misleading us. There is actually a specific coined term for the position you’re arguing, using the same argument, and this is it.

Common sense has lost out quite a lot in science. Einstein himself, for instance, criticized quantum mechanical models, arguing that if they were true, we would expect nonsensical things like quantum entanglement, so we should be pretty sure that the models were wrong. Unfortunately, reality came back with a resounding “screw you Einstein, quantum entanglement is totally a thing.”

Math, on the other hand, has a much better track record. We do not have a history of mathematically proving that something should never happen, for instance, and reality comes back and says “tough, I’m doing it anyway.” We have a track record of working out mathematical formulas that work when you apply them to abstract numbers, and then when we use mathematical models to try and make predictions about the real world, they actually work. Do you know how black holes were discovered? First, people did the math, based on our models of physical law, and found that if you plug the numbers in, if you pack enough matter together, black holes are what you get. It wasn’t until years later that we made the observations that showed that black holes really do exist.

This is why scientists use mathematical models of reality, not just “common sense.” It works. If it were easier than common sense explanation, we would have been doing this thousands of years ago, but it’s not. And so the people who have computers, satellites, phones and airplanes, are us, the people living in a civilization founded on the fruits of science, and not the human race preceding the advent of science. It’s hard to argue with consistent, reliable results.

• Well said. Personally, I prefer this argument for science.

• You know, that comic has always bugged me a bit. The quantum electrodynamics bit makes sense, but I see no way all that GPS devices are dependent on relativity to work. To get them to work right, we have to design them to account for the predictions of relativity, rather than just classical mechanics, but if the universe ran on classical mechanics rather than relativity, I can’t see any way in which it would prevent us from creating GPS devices; it seems to me that it would be even easier.

Relativity has loads of experimental support, but unless you count nuclear energy, which was already observed before the advent of the theory of relativity, if not explained, then I’m stuffed for examples on how industry’s benefited from it being true.

• Relativity works describing reality, so companies are making a killing using it to build accurate GPS devices. A bit more roundabout than some of the others, but doesn’t seem “wrong”.

• But unlike all the others, if Relativity weren’t true, they’d still be able to do that. They’d just do it by not incorporating the predictions of Relativity.

If electricity worked by classical models, we wouldn’t be building semiconductor circuits differently, we wouldn’t be able to build them at all. All the others could be implemented for initiatives that would be possible if they were real, but impossible otherwise, so Relativity is the odd one out.

• There are doubtless other models by which electricity could hypothetically work that would allow circuits that do interesting things. I don’t see where the focus on specific “classical models” is drawn from.

• I did not know that the GPS—relativity connection was wrong. Thanks.

• Well it’s not so much that the connection was wrong. It just didn’t fit the pattern of “If this were real, people would be making a lot of money from it”. Because relativity doesn’t make GPS easier or cheaper. It’s just that if relativity were false, our GPS systems would be constructed differently.

• Failing to fit the pattern counts as wrong. The comic I cited is making an implicit assertion that that pattern holds, and this assertion is wrong.

• To get them to work right, we have to design them to account for the predictions of relativity, rather than just classical mechanics, but if the universe ran on classical mechanics rather than relativity, I can’t see any way in which it would prevent us from creating GPS devices; it seems to me that it would be even easier.

Yeah, the comic seems to be missing the mark there.

Still, if we designed them to work taking into account relativity, and the universe ran on classical mechanics, then they would not work.

• I almost typed out a long reply to this, but honestly, that would have been pointless. You are making the same mistakes, not simple points of disagreement, but very obvious and demonstrable mistakes, over and over. Please read the Mysterious Answers to Mysterious Questions sequence before replying to any more of my comments, if you want me to respond.

• OK, I will. I told you I would, but I have to answer all the responses. I will do that regardless of weather I think it is pointless, because I think it is respecting the forum.

But it would be helpful if you point out my mistakes. What if I read all this stuff and then still make the same “mistakes.” How will I ever know?

I am beginning to think it is a diversion. 2morrow I will read it all and I will be back.

• OK, I will. But it would be helpful if you point out my mistakes. What if I read all this stuff and then still make the same “mistakes.” How will I ever know?

I am beginning to think it is a diversion.

If you continue to make the same mistakes after reading the sequence, the members here will continue to point them out, up to the limits of their patience.

Telling you to read the sequence is a diversion, in that while I could explain the same material myself given enough time, I would really rather not deal with responding to several simultaneous posts making the same mistakes over and over for the time it would take to cover all the material, given any alternative, and would much rather have the time to refresh my patience while you cover it on your own.

• Good enough. Since I am demonstrating intellectual honesty and openess by reading everything you ask, can we agree to this? If I say I understand it but but that I disagree, will you then try to make the case for this half-silvered mirror experiment, or are we done?

Thank you for your patience. It is really appreciated.

• I would ask you to explain the basis of your disagreement. If I felt like we were making any headway in mutual comprehension, I would be willing to make a case for the half-silvered mirror experiment, otherwise not.

• So much for proof. So much for truth.

The map is not the territory, and of course we can’t expect certainty in our map. That doesn’t mean the territory isn’t there; it just means we update our map as we find new things.

• Suppose you have one theory that is very intuitive and easy to explain to a 6 year old but strongly conflicts with all of the experimental evidence you’ve collected, and another theory that is very counterintuitive and bizarre-looking but is heavily supported by the evidence. Which is more likely to be true? The second one, of course—when intuition conflicts with strong evidence, it generally means that your intuitions are flawed.

That’s essentially the situation we are in with respect to QM. It is clearly, obviously true given the evidence we’ve collected, and no amount of intuition can change that.

• That’s more or less what philosophers tended to do back in Classical Greece. Unfortunately, it doesn’t actually work very well.

The less information you have, the less good a position you’re in to come up with plausible hypotheses. If you try and draw a map of a city before you go out and see what the city actually looks like, your map will almost certainly be wrong. Experiments are the “go out and look” step.

What sounds to you like a rational hypothesis might be very obviously wrong to someone who’d actually made the relevant observations. You could end up doing a whole lot of work theorizing and putting together a coherent model, and then go out and do your experiments and find that your theory is completely wrong and gives you nothing useful to work with. You could have saved a lot of effort by going out and looking and finding what observations your theory needs to account for.

Drawing your conclusions before doing your experiments is not just putting the cart before the horse, it’s worse. It’s like putting the cart in front of the horse in a narrow alleyway where it’s a nightmare to get them turned around again. Humans naturally get fixated on and attached to explanations, and once you’ve latched onto an idea, it tends to affect how you view all the new information you get. By the time you raise an explanation to the level of attention, you really should have enough information to home in on that particular explanation out of the whole space of possibilities.

• I think you two may be talking past each other here. You clearly would do some observation before hypothesizing or theorizing, just perhaps not as much. I think the real difference between your positions lies in how you’re defining a theory or an explanation (as opposed to a description of appearances). The explanation that QM raised to a level of attention was not an explanation in the way you probably mean, but more like what you may call a description, like a summary of observations.

• If someone says that square circles exist and they have the math to prove it, do I need to check their math?

If someone had a theory that made useful predictions about the behaviour of reality, and could be used to make cool technology like transistors, and the only way you could get it to work and give those predictions was to assume the existence of hypothetical, mathematical square circles, who are you to call that theory “wrong” or “false”? The universe isn’t obligated to be easy for us to understand, any more than it’s obligated to be easy to understand for a mouse.

• I would say the theory was poorly communicated, at best.

• Theories didn’t make transistors. People did at Bell Labs with trial and error. Predictions had nothing to do with it. Math had nothing to do with it.

I’m sorry, but historically speaking, this just isn’t true. See this page for details. Basically:

This idea that particles could only contain lumps of energy in certain sizes moved into other areas of physics as well. Over the next decade, Niels Bohr pulled it into his description of how an atom worked. He said that electrons traveling around a nucleus couldn’t have arbitrarily small or arbitrarily large amounts of energy, they could only have multiples of a standard “quantum” of energy.

Eventually scientists realized this explained why some materials are conductors of electricity and some aren’t since atoms with differing energy electron orbits conduct electricity differently. This understanding was crucial to building a transistor, since the crystal at its core is made by mixing materials with varying amounts of conductivity… Electrons acting like a wave can sometimes burrow right through a barrier. Understanding this odd behavior of electrons was necessary as scientists tried to control how current flowed through the first transistors.

It was people in the lab who created transistors, using trial and error to get just the correct mix of elements in the semiconductor crystal, but they knew it was remotely possible because the math of quantum mechanics predicted (and this was already verified in experiment) that electrons could ‘tunnel through’ an apparently non-conductive barrier–thus ‘semiconductor’. According to classical understanding of the atom, this wouldn’t happen, and so no one would try making something like a transistor, by trial and error or by theoretical prediction or whatever.

• As far as I can tell, math has nothing to do with explaining the universe.

You’re just wrong. You just got told how the theories you consider ‘worthless’ make correct predictions and allow us to build cool stuff. The theories which you allow ‘make sense’ make incorrect predictions. When your “Monkeymind” disagrees with the universe the universe wins and you lose.

• “Are you going to tell me 0 dimensions make sense?” No, but we might ask you why you take intuition as the basis for accepting truth at all. That’s a pretty big implicit assumption you’re making.

“Theories didn’t make transistors. People did at Bell Labs with trial and error. Predictions had nothing to do with it. Math had nothing to do with it.” Ah. The people did it without theories, math, or predictions? I’d like to know more! Because I don’t know how one would go about constructing anything, e.g. a transistor, otherwise. You mineswell walk into a lab with equipment and randomly jam things together. (Heya, cat? ‘Meow’ Wanna help me build a transistor? ‘Meow’ Okay, let’s place you on top of this computer, maybe that will do something—I don’t know, because I don’t even theories! ‘Meow’ Hm, that didn’t work. But at least you look warm, curled up on top of my computer tower—oh wait, I’m still making inferences based on the prediction that temperature evens out, which comes from my theory!--so I guess you might be freezing for all I know)

• Your comments will be a bit easier to read if you use > to start quoted text. (Make sure to leave a line separating them and your response, or they’ll be part of the same paragraph.)

• OK, I am sorry I responded to your insulting post in kind. I was afraid it would come to this. First I am accused of trolling. Not being serious and not understanding. Now insulting responses.

I have learned to expect this when I challenge religious folks beliefs, I didn’t expect it from this community.

However, I can take and dish it out -if that’s what you want. Otherwise. I call truce.

• You might still love this community, if you stick around, given your intellectual openness. And you have a good point about the accidental inventions. However, my point about theory—well, it’s so basic that it can’t really be denied. The transistor may have been invented by accident, but if the scientists didn’t have theories about how things worked, they couldn’t possibly have messed around with things in the right away to come up with accidental inventions on top of purposeful inventions. Like I said, if you truly had no theories, you mineswell stick your cat on top of your computer tower to make a transistor.

And I’m still puzzled about your response to Swimmer963′s comment. Do you really think that if a theory, that made no sense at all to you, but nevertheless made many successful predictions and was even the basis of a new technology, you still wouldn’t believe it? Because, if that’s so, then you’re just stupid. Your comments indicate you’re not actually that stupid. That’s where I got the “you take intuition as the basis for accepting belief” comment, because your reply to her (I think Swimmer is female and has written posts on her) indicates that you do in fact take your intuition—“but that just can’t be”—over empirical demonstration.

• Are you going to tell me 0 dimensions make sense?

As long as it doesn’t introduce any inconsistencies in the mathematical theory then sure. It’s a game with symbols that we can use to model real-world systems.

• Hypotheses describe and theories explain. If they don’t make sense they are worthless!

Theories don’t explain- they predict. Consider gravity- Newton’s law tells you the attraction between two masses, and it’s mostly consistent with the mostly elliptical orbits that we observe the planets moving in.

But why does gravity exist? Why does it take that particular form? The theory is silent. It tells you how things will behave, but offers no further explanation.

If you can tell me how anything can have 0 dimensions in reality

So, electrons have mass, and charge, but as far as we can tell their radius is indistinguishable from zero. Does that count as 0 dimensions for you?

• Theories don’t explain- they predict. Consider gravity- Newton’s law tells you the attraction between two masses, and it’s mostly consistent with the mostly elliptical orbits that we observe the planets moving in.

The gravitational equation is effectively just* a summary of the observed data, so it is no surprise that it predicts. I believe Monkeymind finds this unsatsifactory, but I’m still not sure exactly how. Perhaps he defines theory differently. I’m a little curious what actually causes the Earth to pull on me, rather than, say, push me away. At the time Newton said he had no hypothesis for that, but now the same equation constitutes a theory or explanation? I feel like these terms are used a little too loosely.

*Not to imply that finding the equation that fit the data wasn’t an important achievement

• “Theories predict, but do not explain? What good is that?”

There’s a reason we ask new people to learn a little bit about the LW community before posting. Anticipation of experience as the measure of your belief is a fundamental concept here.

You can think of it this way: a good explanation lets us make many new predictions. And that is the sole use of explanation. (Does that sound too strong?)

EDIT: Really good explanations can be formulated mathematically, and from mathematical ‘laws’ you can derive predictions, as Desrtopa implies about Newton’s laws.

• That’s the problem. Theories predict, but do not explain? What good is that?

… prediction?

I could care less that you tell me an apple falls at whatever ft per second per second.

The artillery captain cares strongly, not just the precise rate at which gravity occurs, but also the precise rate at which the world turns. And a nation whose shells land on target will conquer a nation whose shells miss their targets.

That is, you should care strongly about predictive success in any field personally relevant to you.

I want to know why.

Turn things around: what good is that? Suppose you knew why, but so broadly that it wouldn’t help you differentiate likely futures from unlikely futures (i.e. prediction). What could you do with that?

Something that is indistinguishable from zero just means that it is very small and approaching zero.

What’s the electrical charge of a neutron? How do you know?

If there is no L, W, or H then it has no dimensions. How can that exist except as a concept in some abstract mathematical model?

Edit: I misread what you wrote. To respond to what you actually said: are you doubting the existence of electrons?

I’ll wait and see what EY has to say about it, but honestly, I’m not very confident that he can make sense of arrows that point nowhere.

EY comments infrequently, so I would not hold out too much hope that he’ll address your concerns.

• I suggest that you read the Mysterious Answers to Mysterious Questions sequence, if not the whole thing, then posts 1, 2, 5, 7, 8, 9, and 11-18. If that sounds like a lot of reading to do, that’s because quite a lot of work has already gone into explaining the problems with the approach you’re suggesting.

• OK, I will do this later today or tomorrow, but unless you wrote the article, I’m not sure we can properly address all the issues that may come up. I will relate everything that you throw at me directly back at this particular article. Already though that has it’s own probs. You told me you didn’t think that EY was talking about arrows that do not point anywhere. You said, in effect, that you weren’t sure. He might actually be saying that.

So I hope you can see why I do not just accept authority blindly! I am not trying to be difficult. I just am, so it comes out that way!

• Not accepting answers simply on authority is good. That’s one of the foundational ideas of science. But if scientists demonstrate an understanding that allows them to produce stuff that they otherwise wouldn’t be able to (and quantum theory definitely delivers on this count,) it’s worth taking the likelihood that they know what they’re talking about very seriously.

Some scientific subjects are difficult to understand, and take a lot of time and effort to build up to.

To quote from one of Eliezer’s other posts

Modern science is built on discoveries, built on discoveries, built on discoveries, and so on, all the way back to people like Archimedes, who discovered facts like why boats float, that can make sense even if you don’t know about other discoveries. A good place to start traveling that road is at the beginning.

Don’t be embarrassed to read elementary science textbooks, either. If you want to pretend to be sophisticated, go find a play to sneer at. If you just want to have fun, remember that simplicity is at the core of scientific beauty.

And thinking you can jump right into the frontier, when you haven’t learned the settled science, is like…

…like trying to climb only the top half of Mount Everest (which is the only part that interests you) by standing at the base of the mountain, bending your knees, and jumping really hard (so you can pass over the boring parts).

Don’t be so hasty to try and jump into the advanced stuff. It’s built on lots and lots of developments, and if you don’t take the time to understand those, it’s necessarily going to seem confusing, whether or not the people working on it really know what they’re talking about.

Ultimately all science has to eventually be used for prediction or it is useless except for aesthetic purposes. However, I do sympathize with what (I think) your main point was before, that prediction is no measure of a theory if the “theory” is just curve-fitting (it is, of course, a measure of the utility of the curve or equation that the data was fit to). That is really just common sense, though, so you may have meant something else.

• If you have enough information, you can use Newton’s laws to predict when an apple will fall, or work out whether a bridge will stay up before you build it.

If we worked out this “why” you’re talking about, can you say what it would actually do for us?

• Well, knowing what quantum theory tells us about light has allowed us to do a whole lot of stuff we weren’t able to do before, most prominently everything that we can do with lasers (which are not predicted to exist at all by classical theory, but were predicted advance by quantum theory, and then created because they had already been predicted, so researchers had an idea what to aim for.)

In any case, if you can’t give an example of any question and how you think scientists would have attempted to answer it compared to how you would have answered it, and why you think that would give superior results, why do you think you know better?

• x AND I don’t think I know better. I only suspect that the SM I am describing will get better results because the principals make better sense than what we are currently using.

But I want to elaborate on something I said about why questions. Been thinking about this the last few days, after being asked what good is knowing why.

You ask why and: your parents say “Because I said so.” your teachers say “because smart people say so” your preachers say “because the bible says so.”

You get tired or maybe conditioned by this and so: You stop asking the why questions.

If we had more of the why answers maybe the what questions would make more sense. Maybe we would have less what questions.

• Whoah, thanks for this. I get what you’re saying now: you oppose Ptolemaic explanations. I think these are good points—why’s this sensible post being downvoted? Even if there is something wrong with the reasoning, these seem like good, interesting questions to me.

• Einstein said one should be able to explain any theory to a barmaid and Feynman said if you can’t explain it to a 6 year old then you don’t understand it.

I hope they allow about 5 years for them to teach the prerequisite knowledge and allow the relevant neurological adaptations to get in place.

• It is not that I am dull, it is that my questions and ideas are a threat to your religious world view.

You overestimate the threat that you pose. Your ideas are mostly harmless. Actually I believe having you here for a little bit was a net benefit to us. Trying to explain things across overwhelming inferential distance (and to people who are not @#%\$@s) is useful. As is seeing other people attempting to do the same.

All the experimenting with imaginary numbers will not explain a thing about reality. It is relgion plain and simple.

Didn’t anyone tell you? We Believe that Eliezer is the reincarnation of Pythagoras come to share the Good News about imaginary numbers and complex amplitudes.

Well, I was going to describe a hypothesis and rationally explain a theory to you that answers all questions and unites everything. Yes, you heard right, a Grand Unified Theory....but my GUT tells me you prefer “point-less” discussions.

Teehee. You have a Grand Unified Theory that doesn’t use mathematics. That’s adorable.

• As evidenced by his response to your comment, we are well into feeding-the-troll. Please stop.

I admit that this wasn’t clear earlier in the discussion, which made the conversation worthwhile. (especially when he agreed to consider the community argument for empiricism by reading the first sequence) But enough is enough.

• Actually I believe having you here for a little bit was a net benefit to us.

Is this still true?

• Well, I hope it has been a benefit to some. I’m just testing ideas out and wanting to learn and I have learned some things… so great!

Judging from the lack of counterarguments, accusations, dodging, strawmen, shifting of goal posts, and so forth, the ideas I am sharing strike at the heart of folks belief system.

• BYE!

EDIT: What negative thumbs for leaving? I said I’ll be back. Just giving you a chance to gather your thought s so you can answer my questions next time. And when I get back, I’ll know far more than I do now. I’ll either be apologizing for being so dull, or ‘splainin’ why you are dull!

• To be honest, you sound bitter or something, although given the difference of opinion being as radical as it is, that is pretty understandable (so are the downvotes, for the same reason). Maybe let it cool off for a bit. I have an interest in hearing what you think after you have spent more time here.

You remind me of Silas Barta, and I think we could use more people who radically disagree with major pieces of LW, because it is good practice if nothing else.

• You remind me of Silas Barta, and I think we could use more people who radically disagree with major pieces of LW, because it is good practice if nothing else.

Monkeymind seems the very opposite of SilasBarta. SilasBarta often makes excellent points, if at times expressed in a more-obnoxious-than-necessary manner. Monkeymind, by contrast, is cordial enough, but has nothing to offer intellectually.

(Also, if Silas has radical disagreements with major pieces of LW, I haven’t noticed.)

• Bluntly, I don’t think Monkeymind is worth your or LW’s time. They claim that science and mathematics are not used in designing or constructing technologies, reject scientific consensus on the grounds that the informal explanation is unintuitive, and purport to have discovered a (mathless) Grand Unified Theory. Disagreement can be handy, but it needs to be a little better thought out.

• I’m sorry the universe is unintuitive, but there are better ways of dealing with it.

• Hi Cu, and thanx! This is what I have been saying all along.

Maybe, I misunderstand what you mean by intuitive, so perhaps you should give your definition. If we wish to make an appeal to popularity, we can use this Google definition (which I have posted b4):

Intuition: Using or based on what one feels to be true even without conscious reasoning; instinctive.

Based on that definition, you can see clearly see that I have not been saying that at all. I have repeatedly said that in a hypothesis one must rationally define their key terms. It seems like you and others here are guilty of basing your “beliefs” on what you feel to be “true” based upon what you have been told, and not by actually applying the scientific method.

It is a shame that I have to repeat myself so often because folks refuse to actually read what I am saying.

• Well, if you have a legit Theory of Everything, I’m sure we’ll hear about it someday. But if you mail it in to some professor and hear back that it’s got a three digit score on the crackpot index, well, you’d better be prepared for a hard trek to show why your theory of everything is better than the countless other theories of everything that get sent in to them every year.

• x

• I downvoted your post because it was long, rambling, and spilled over into a cascade of sub-posts which I didn’t read. However, if you re-wrote your post as an article, with proper headings (not to mention, narrative structure), I’d gladly read it.

• Well then you missed the series of posts (the last few) that begin with:

“Well, I know that I said I would be back in a few months after learning more, but that will not be necessary. I have already learned enough to complete my analysis of Configurations and Amplitudes.

So today I wrote up a brief response based on what I currently understand about Double Slit and Half Silvered Mirror Experiments. Here it is in several posts.

What’s the matter?”

BTW, the post I was talking about was 13 sentences. I don’t know which one you are referring to. Anyways, try to respond to content not style. See if you can exterminate any of my posts, Bugmaster. I welcome it, as I’m here to learn, not defend some sort of belief system.

• Once again, I downvoted you because:

• Your posts are very hard to read in this cascading thread format. If you formatted them as a top-level Discussion article, they’d be easier to absorb.

• Your writing is rambling and disorganized. If you organized your words into blocks of several paragraphs each, with proper headings that follow a logical outline, then your point would be easier to grasp.

• Your tone in general is very aggressive. You keep saying stuff like “do this !” and “don’t do that !”, but you’re not the boss of me. There’s nothing wrong with an aggressive tone per se, but it’s much easier to swallow when it’s backed up by some unimpeachable reasoning and evidence—of which you offer very little. Well, perhaps you do offer some, but I didn’t see it, because your posts are so hard to read (as per the previous two bullet points).

• Thanx, Bugmaster for splainin your thumbs. It is appreciated. The cascading thread format is not my choice, I much prefer SMF over the blog post style, but that’s what we have to work with. You post and I respond, hence cascading posts.

My writing has been consistent throughout and very organized, which you would know had you taken the time to read them. It took all the posts up until today to get folks to discuss my primary concern (from post one) defining key terms, because it is other members trying to divert the subject matter which is the experiment is flawed because the key terms are not defined or are inconsistent.

The aggressive tone is partially my style but partially stems from others accusing me of being a troll, thumbing me without explanation and refusing to stay on topic. No one has offered a single challenge to my content.

I do not know what you are referring to when you say that I am telling you to do this or not do that, but would like to point out that I was told by one member that I just don’t get it, and that I needed to read such and such if I was going to get any further discussion. I have complied with these demands and have read through dozens of EY’s posts. In fact, you’ll notice that I used quite a bit of his own words to illustrate some of the things that am trying to get across.

In stead of dealing with the issues that I have brought up, I get posts like the ones you are making dealing with style not content. It is your choice to read or not read what I am saying. I am not tied emotionally into the outcome at all, I came to learn about the half-silver mirror experiment and how it is related to SR, GR and QM. I originally thot this was a physics forum because of the topic. Now here you are telling me “You’re not the boss of me” and at the same time telling me how to compose my posts, so that you will read them. How about some counterarguments instead?

• OK, I answered every single post addressed to me. I have done this since the beginning nearly one month ago. I have been honest, open and direct. I have tried to understand the community and I have done my best to respond with as much detail as needed to answer the issues raised.

No one has responded in kind. Therefore, Monday I will be back. If anyone needs clarification on anything that I have said, I will respond. Be prepared to answer my questions and address the issues I have raised by relating it directly to the OP (configurations & amplitudes). Otherwise I am done with this thread.

NOTE: the primary issue is defining the key terms related to the OP and dealing with the propagation of light as a particle/​wave.

• If you have a problem with mainstream physics, please take it up with physicists.

This is a site about the art and science of human rationality. This post was just a part of the Quantum Physics sequence, which was arguably tangential to the overall aims of the site. The author is not a physicist, and is merely reasoning using established math and physics.

I’m sure there are places on the Internet devoted to the discussion of physics. I believe your comments would be much more productive there.

• You’re making a ton of interesting points, but please succinctify (a lot!). I mean, let people reply and stuff. I feel sorry for you writing all that knowing almost no one will see it. It’s obvious you’re reading LW classic posts and making discoveries, and then immediately turning around and applying them, which is great. I just think you’d do well to steep yourself in the posting norms of this forum so you can participate in a more fruitful way. Again, I for one would like to hear well-reasoned radical views.

• The style of this comment is preferable to previous ones, but it is still too long and off-topic.

This looks like it might make a good blog post—though I would recommend your own blog rather than a discussion post here. A Tumblr is easy enough to set up, and then you could write a comment like “Detailed arguments [here] (link)”.

Although it is long, as it broadly covers many blogs in a sequence on how to change your mind, I disagree about it being off topic.

However, let me remind you that it is others that have kept it “off topic” not I. Others requested that I read other blogs in order that I might see more clearly where the author was coming from and the main thrust of Less Wrong.

Yet, it is not entirely off topic, it is just that we are dealing with a very broad subject, Quantum Mechanics, and attempting to approach it from a rationalist pov. The specific topic is Amplitudes and Configurations. The foundational principles of the experiment are flawed. I have attempted to point this out. We can return to the actual experiment once we have agreed on the basic assumptions.

• I am not a physicist, but my understanding is that “travels along a sinusoidal path” is not the same thing as “is a wave”.

• Exactly! Wave is a verb, a dynamic concept implying motion and concepts can not move. ADDED: Adding ‘A’ in front of wave makes it appear it is a noun.

One does not need to be a physicist to understand that light is not ‘a’ wave.

There is a difference between an object and a concept. I keep saying this over and over, not because I think anyone is stupid. Because it can take months to understand (unlearn bad habbits). This is the MAIN prob with science in general and math and physics in particular.

BTW: dlthomas, I plussed you for helping me FINALLY get to the Thingy. Defining KEY TERMS!

• Geesh! You are all thumbs! (bugman)

So what is this WAVE?

“In physics, a wave is a disturbance or oscillation that travels through spacetime, accompanied by a transfer of energy. Wave motion transfers energy from one point to another, often with no permanent displacement of the particles of the medium—that is, with little or no associated mass transport. They consist, instead, of oscillations or vibrations around almost fixed locations. Waves are described by a wave equation which sets out how the disturbance proceeds over time. The mathematical form of this equation varies depending on the type of wave.” http://​​en.wikipedia.org/​​wiki/​​Wave

According to Wolfram: “noun- (physics) a movement up and down or back and forth” http://​​www.wolframalpha.com/​​input/​​?i=wave

A disturbance that travels? A movement up and down? Neither of these is a noun. Motion is not an object it is a phenomena, a disturbance through a medium. (This is one reason why space is now supposedly not just a vacumn but some”thing” a medium which can be warped, or rippled).

C = f (frequency) x lambda (wavelength)

The physicist has defined frequency in regards to time and wavelength in regards to length. The math keeps frequency constant and light moving at different speeds through different mediums like glass, air, space, etc (refraction). So light accelerates from 200,000 to 300,00 kilometers per second when it passes from water to air. What causes this? No one has an answer! Newton’s third Law requires a force and Einstein (relativity) requires a curvature of space to deflect light. The solution offered is waves. Different mediums cause different resistance to the waves. So do these waves convert to particles when they reach a different medium?

Standing wave: Particles move up and down while wave moves through? Right! Imagine a rope tied to a tree on one end and you on the other. Move the rope up and down and watch the rope move in place as a motion “travels” along the length. Wait! the photon is supposed to be a traveling wave where the billiard balls move up and down as well as forward. What makes the billiard balls move up and down? Especially if they have no mass.

Wave motion transfers energy? Another important word! Energy is the ability to do work, that is, 1 J = 1 W s = 1 kg m^2/​s^2. A motion transfers the ability to do work! A motion moves a motion. Right! Another misuse of the English language. Another example of not knowing the difference between objects and concepts, nouns and verbs!

• Do you also object to saying that a surfer is riding “a wave”? Motion is not an object, but a particular pattern of motion can be: a wave, an eddy, a tornado...

No, not if we are talking like a couple of buds on the beach observing a surfer over a couple of beers (and he can shoot the curl all he wants). However when we are talking scientific hypothesis or theory, we have to be using unambiguous, non-contradictory, precisely defined terms that can be used consistently throughout a discussion. If Amplitudes and Configurations wants to use key terms, they need to be defined in this way. I provided definitions from wiki and Wolfram. If one reads through the scientific literature (and I previously listed all the major scientists in chronological order) ones sees that the term wave is used inconsistently. This is why each theorist must define his own key terms (the ones his hypothesis or theory depend upon).

Wave/​particle paradox is irrational because it is contradictory and illogical. That alone should raise flags and eyebrows!

Oh and BTW the ocean wave you are referring to are water molecules moving up and down!

• The theme in my posts all along has been about defining key terms and proper scientific method. We can’t have one without the other. Here is another perfect example of what I have been talking about, when I say proper scientific method.

In the Strange Case of Solar Flares and Radioactive Elements, when the scientists can’t understand how their observations don’t align with their theories, instead of taking a closer look at the assumptions of the theories, they naturally want to invent another particle! (In general, I am pointing to the problem with the Scientific Method. In particular, I am relating this to the back and forth of wave to particle to wave to particle and finally landing on particle/​wave duality).

Because of seasonal variations, researchers think that solar flares may be interfering with the rate of decay of radioactive isotopes on earth (which are supposed to be constant).

“It doesn’t make sense according to conventional ideas,” Fischbach said. Jenkins whimsically added, “What we’re suggesting is that something that doesn’t really interact with anything is changing something that can’t be hanged.”

If the mystery particle is not a neutrino, “It would have to be something we don’t know about, an unknown particle that is also emitted by the sun and has this effect, and that would be even more remarkable,” Sturrock said. http://​​news.stanford.edu/​​news/​​2010/​​august/​​sun-082310.html

Remind you of anything? 0D photons and waves that travel don’t make sense based upon the math and observations, so therefore let’s invent the particle/​wave paradox. Now, instead of questioning the assumptions of QM, researchers are assuming a new particle in order to make sense of something which does not make sense. QM says that nothing can affect the rate of decay of isotopes.

• Uhuh, thanx for the thumb down, mystery person. Don’t worry about it… the physicists don’t have counterarguments either!

Wave/​particle duality is irrational because the language is grammatically incorrect and contradictory (as I have explained repeatedly).

The half silvered mirror experiment, and the double slit experiment are unscientific. The theory they are based upon uses abstract dynamic mathematical language to describe imaginary static objects confusing objects with concepts, instead of illustrating the objects in the hypothesis and explaining the phenomena in the theory as required by the scientific method.

The actual phenomena is simple diffraction caused by destructive wave interference and was properly understood hundreds of years ago.

The particle wave paradox is illogical, because it violates the three Laws of Logic.

Finally, the Lunar Laser Ranging stations in Texas and in New Mexico clearly show the impossibility of light leaving as a photon, traveling as a wave, and arriving as a photon. Therefore, I have shown without any counterargument that Amplitudes and Configurations is nothing but smoke and mirrors.

• I think you are fighting a strawman here. By using the word “wave” physicists are not suggesting that something moves along a sinusoidal path. That was your intepretation, an incorrect one, and you have successfully disproved it, which is great. Just please don’t assume that physicists are doing the same mistake.

When you look at the waves on the water, yes, there is a kind of sinusoidal shape. But the word “wave” in physics means that at some places the density of something is higher, and at other places, the density is lower, and the map of the densities looks and moves… well, like the waves on the water.

The waves on the water make a sinusoidal shape, because there is an air above the water, so the higher density of water creates a “wave” in a layman’s meaning of the word. But imagine an explosion deep below the ocean surface, and how the density of the surrounding water changes in time. This is also called “waves” in physics, but there is nothing moving along the sinusoidal path. Similarly, sound makes “waves” (areas of different density) in the air. And a photon also makes some kind of a “wave” (some its properties measured in space and time show the same kind of pattern).

• Instead of talking about details, I’d like to remind you of the big picture.

You think physicists get it wrong and you get it right. That is not completely impossible. However, based on the theories of physicists we have a lot of stuff that works: planes that fly, microwaves that heat, GPS devices that measure your position. So if their theories are wrong, how do you explain that all this stuff, built on their theories, works? Their theories, if not completely correct, must be at least approximately correct, or mathematically equivalent to correct, right? So even if they make errors, they surely do not make obvious errors. However, what you write, suggests that there is a big difference. How is it possible, if you are right, that a theory so different from yours can still produce all the stuff that works?

(To compare, LW contains a few discussions on many-worlds hypothesis versus collapse hypothesis, but those two are mathematically equivalent. In other case, an experiment could be done that decides between them, and someone would probably have done it decades ago.)

• So if their theories are wrong, how do you explain that all this stuff, built on their theories, works?

In short, the hypothesis User:Monkeymind advanced (somewhere in that rambling mess) was that engineers do not base their technological work on math, but instead on trial-and-error. This is obviously an empirical question. Monkeymind offered as evidence that he himself has a bad grasp of mathematics and yet has built various devices using trial-and-error.

It’s a potentially interesting idea. Do we have any real evidence that mathematics is a necessary component of the development of these devices? Anecdotally Norbert Wiener used mathematics to shoot down Japanese planes using radar.

Not that we have a really good alternative. Physical theories have been preferred for being more mathematically elegant ever since Newton, and before that we didn’t really have physical theories. I think that Monkeymind’s insistence that science is not for making predictions might be a hint that we’re just talking about different things here.

• Doesn’t look like a definitive answer to me, though it does answer somewhat for that particular example.

• Agreed, it’s not definitive. The best way to answer this would probably be to round up a bunch of engineers and ask them how much they use math. That would give us a quick average estimate of how today’s engineers use math. Unless you’re interested in specific important discoveries in engineering, in which case it would make more sense to examine the most influential breakthroughs case-by-case.

• I personally am a programmer, but the software I write (as well as other software, written by smarter people) is used by genetic engineers. They engineer plants for specific desired traits (stronger drought resistance, bigger fruit, whatever). To do this, they use a ton of conventional math (statistics, specifically), as well as numerical optimization methods (such as neural networks) in order to determine (simplistically speaking) which nucleotides on the genome have an effect on which trait.

A single chromosome of corn consists of about 200,000,000 nucleotides. Good luck with that trial and error !

• Yes, and a grain of rice has more genetic material than a human (almost double). So what?

With the simple understanding of emergent complexity, and without any automata or math at all, I can tell you (predict) what any plant or animal will look like on a mountain above 14k feet, or in a tundra. It is because there are only a few configurations for plants or animals in those conditions. We know this because we have observed it over and over again. So I can predict various life forms quite easily.

Although an electron microscope and a great deal of programming was needed at various stages, Craig Venter’s Synthetic Genomics has synthesized an e-coli bacteria. Using four chemicals they created a synthetic bacterial chromosome and used yeast to assemble the gene sequences. They were copying nature, not actually creating anything from scratch. Lots and lots of trial and error was involved. Watch his press conference and let him tell you himself. Professor Cronin of Glascow University has created self replicating, evolving inorganic (metal-based) iCHELLS almost entirely by trial and error mixing.

I’m very excited about their accomplishments and have corresponded with both of them to let them know. I’m not knocking science or those respectable persons involved in the scientific process, I merely want to help make it better.

I am not for getting rid of theory and replacing it with trial and error. Try to actually read what I have written in toto instead of taking a few phrases out of context.

• In short, the hypothesis User:Monkeymind advanced (somewhere in that rambling mess) was that engineers do not base their technological work on math, but instead on trial-and-error.

A hypothesis that collapses into category-erroneous incoherence as soon as you realize that math can also be done via trial-and-error.

• With minus 373 Karma points for the last 30 days under your belt, I think you should take a hint and stop posting. If this comment is upvoted/​not convincingly disputed (by others), I’m going to start removing some of the worse comments you make in the near future.

• Please crack down earlier, harder, and more often. Nobody is going to die from it. Higher average comment quality will attract better commenters in a virtuous circle. There’s no excuse for tolerating the endless nonsense that some commenters post, and those enabling them by responding to them should stop.

• those enabling them by responding to them should stop.

This seems to be the main problem, but my recent attempts to discourage those who make high-quality contributions to hopeless or malignant conversations didn’t stir much enthusiasm, so it’d probably take a lot of effort to change this.

(A specific suggestion I have is to establish a community norm of downvoting those participating in hopeless conversations, even if their contributions are high-quality.)

Please crack down earlier, harder, and more often.

This is something new for LW, in fact this appears to be the first time when a non-Eliezer moderator stepped forward to implement this measure (in this case prompted by Eliezer’s recent statement that deleting posts by a chronically downvoted user who doesn’t stop is to be considered a general policy).

• my recent attempts to discourage those who make high-quality contributions to hopeless or malignant conversations didn’t stir much enthusiasm

FWIW, you brought me around on this point.

• This is the first time I’ve come across the suggestion to downvote well-thought-out contributions to silly conversations, actually, and I like it. I’ll keep that in mind.

• A specific suggestion I have is to establish a community norm of downvoting those participating in hopeless conversations, even if their contributions are high-quality

How do you define “hopeless”, exactly ? Sometimes, a high-quality post in response to a troll’s or idiot’s thread can be quite helpful to other readers (and lurkers), who aren’t trolls or idiots, but who are just misinformed or new to the topic. I personally have been such a lurker on several sites, but I do acknowledge that my personal experience is not statistically significant.

• my recent attempts to discourage those who make high-quality contributions to hopeless or malignant conversations didn’t stir much enthusiasm

I generally regard it as a norm that one should not respond to trolls and the like.

But I ignore that norm when I see the opportunity to help someone.

• I’m generally against ban-level measures, as such measures are very damaging and the comments don’t seem particularly so.

• such measures are very damaging

Why?

• Just a few reasons: Removing comments happens silently and without a trace. Such tools can be used by the establishment to quiet dissent. They can break existing conversations. We need more contrarians, not fewer. By removing examples of what not to do, we can no longer point at them as examples. Even if the comments were on the whole annoying, there might be interesting stuff in there worth responding to. Bans, more than downvotes, outright discourage participation amongst those who are in particular need of our help. Freedom of speech is valuable in itself, and its presence here is aesthetically pleasing.

• The current procedure: (1) banning mode is only triggered by a user systematically accumulating some crazy amount of negative Karma quickly, (2) you get an explicit statement of banning-mode having been triggered, where others can appeal/​discuss the decision, (3) you are free to continue participating if you somehow manage to produce the kind of comments that don’t get downvoted (so it’s more of a parole). In no other cases do the comments get banned.

• Yes, and it’s carried out by Vladimir_Nesov and his ilk, which makes me not worry at all about the application in this particular case. I still needed to register my general objection, and I fear for our children’s children who might suffer under an oppressive fascist regime based on the Less Wrong moderation policy.

• If this is where we are at, then please advise me of it so I can take appropriate steps to avoid getting banned. I don’t think I got an explicit statement of banning mode having been triggered, but I want to be sure since there is talk of the ban hammer going down.

I am not trying to be contrary, I just am, so it comes out that way. I truly think that what I have to offer has merit. Of course, if the community does not think so then it is within their power to down vote me into non-existence. That is fair, as I have no right to force my ideas on another person. It just seemed that this would be a place to share ideas. Perhaps not.

• The “statement of triggering the banning mode” is this. The steps to avoid triggering it (in your case, to get out of it) are here. This is the conversation where the procedure is getting established.

• Removing comments happens silently and without a trace. Such tools can be used by the establishment to quiet dissent.

So let’s have a policy that banned commenters get to post a link to their anti-LW blog. We could list all the anti-LW blogs on a wiki page or something.

They can break existing conversations.

By removing examples of what not to do, we can no longer point at them as examples.

I don’t think anyone is proposing to delete past comments.

We need more contrarians, not fewer.

If I promise to be a high-quality contrarian, can we ban the next five low-quality contrarians?

discourage participation amongst those who are in particular need of our help

This is a good thing. LW’s positive impact is likely to lie mostly in building an effective movement, figuring out what issues are important, and pushing on those issues; all of these are helped by a high average level of rationality. LW’s positive impact is unlikely to lie in trying to fix whatever hopeless cases wander by.

Freedom of speech is valuable in itself, and its presence here is aesthetically pleasing.

I disagree on both counts, and I suspect your other arguments may be rationalizations springing from this value judgement.

• I’m generally in favor of more contrarians on LW, but a commenter who rejects empiricism across the board and cannot make any comments trying to understand the arguments in favor of empiricism adds no value here—especially if rejecting empiricism is all he is willing to talk about AND his comments dominate the sidebar for days.

In short, banning is a reasonable measure in this case. That said, I agree with your general points below.

• ...but a commenter who rejects empiricism across the board and cannot make any comments trying to understand the arguments in favor of empiricism adds no value here...

You are probably right about this particular case, but I’d hesitate to generalize it to all possible cases. I personally would find it quite interesting to engage in conversation (or debate) with a staunch anti-empiricist, assuming such a thing was even possible. I have talked to a few anti-empiricists before, and I find their position fascinating… listening to them feels like getting a glimpse of an utterly alien mind.

• If you’ll start a discussion topic or a thread somewhere on the issue, I’ll argue against empiricism. We should trade understandings of what we take empiricism to be first though. Let me know if you’re game.

• I’m totally game, but I am unskilled in the ways of LW. How do I “start a discussion topic” ? I thought that discussion topics had to be full-fledged articles, according to LW etiquette. I could probably sum up my position in a few bullet points, but I don’t think I have a full article’s worth of material.

But I could be overthinking the whole deal, let me know if that’s the case.

• Alternatively, y’all could just have this conversation offline, via email or PM. If it turns out to be valuable, you could turn the conversation into an article.

• I guess you could start an article in the discussion section? I don’t know the etiquette very well here either.

The empiricist claim that I would attack is one which says something like this: we have two ways of coming to know something. First, we come to know things by making inferences from other things we already know, and second we come to know things by direct experience of them. The second way, direct experience, is of something like sense-data. At root, everything else we come to know, we come to know by way of sense-data, and our access to sense-data is independent of whatever we infer from it.

That’s the view that I’d attack. I think any theory of empiricism weaker than that isn’t really distinctively empiricist, or distinguishable from, say, many versions of coherentism. But I’d be willing to debate that too.

• That sounds like a good starting point to me. We could discuss this via PM, as TheOtherDave suggested; this way, if our discussion turns out to be nothing but noise, we would at least spare the other LWers the aggravation. Alternatively, I could create a discussion post containing the above paragraph, and my response, and we could go from there.

Both of these approaches sound good to me, so let me know what you want to do and I’ll get crackin’… by which I mean, I will write up a response when I have time :-/​

• On the contrary, the karma system exists in order to make such “cracking down” unnecessary. If comments are downvoted sufficiently, they are hidden. This system is supposed to replace moderator action. If moderators are going to control content then we may as well not have voting.

I’m speaking up in this instance in particular because it seems to me that the only problem with the commenter in question is an intellectual one. The person isn’t behaving badly in any sense other than arguing for an incorrect view and not noticing the higher level of their opponents (which after all can hardly be expected). It’s exactly the kind of thing that downvotes alone are supposed to handle. We’re not talking about a troll or spammer.

The reason it’s important to make this distinction is that censoring for purely viewpoint-based reasons is a Rubicon that we need not cross.

(EDIT: I’ll also point out, for clarity, that I myself have not responded to any of Monkeymind’s comments. Being opposed to banning a commenter is not to be confused with being in favor of engaging them.)

• There is a point at which not getting the message from karma is sufficiently damaging to the community that moderator action is called for.

• Karma does not merely send messages to the user, but actually does the work of moderation by causing comments to be hidden.

• On the sidebar too? That’s the most aggravating issue, to me.

• If that’s the problem, shouldn’t the solution be to implement comment-hiding on the sidebar?

• Comments in the sidebar tend to be too new to have been voted below −3 or whatever the threshold is.

• One could make the sidebar-threshold lower than the ordinary threshold....

• True, but it would discriminate less well. It would hide many OK comments that happened to be downvoted once or twice.

Note that for this solution to be an argument against the banning solution, it would need to actually be implemented. Are you predicting that will happen?

• I’m saying it ought to be done, if the problem is as described. Or, in other words, that I prefer such a solution over the alternative being proposed (moderator intervention to remove comments).

• So you’re not saying that you prefer no banning to banning (given whatever you predict will actually happen to the sidebar)?

• I thought I was saying that.

• Preferring sidebar change to banning does not imply preferring no banning to banning given actual probability of sidebar change. Do you agree?

• Actual probability of sidebar change is, I would hope, dependent on such preferences.

• There are some corpses in the street. Some people are proposing to bury them, because they’ll rot and cause diseases. Others are proposing to leave them there, because haha, corpses. In this situation, you may prefer cryopreservation to burial and at the same time prefer burial to non-burial, because cryo probably won’t happen. (Maybe this is an insane alien hypothetical world where cryo is just really unpopular.) If you’re facing a “bury yes or no” button, it may well be rational to push yes. This is true even though the probability of cryopreservation depends on your preferences. Now substitute bad commenters for corpses, banning for burial, and sidebar change for cryo. I’m not saying the parameter values are the same, but do you agree with the qualitative point?

• I agree with the qualitative point but think it irrelevant. Not only are we not facing a “yes or no” button, but all that you claim in the above is that it “may well be rational to push yes” (emphasis added) in the event that we are faced with such a button. This says very little.

Again, I reiterate the point made in the grandparent. A hypothetical about a yes-or-no button is no answer to someone specifically advocating a third alternative. If you don’t think the third alternative is possible, argue against it directly; don’t pretend it was never proposed.

• It is nonetheless some number smaller than 1.

• The question isn’t whether it “exists in order to” make cracking down unnecessary, or whether it “is supposed to” replace moderator action. The question is whether it actually does those things. And it’s far from perfect at doing them. Yes, heavily downvoted comments take up a little less space in the recent comments and in the thread (at least if you have the willpower not to click on them! virtue of curiosity!) But they still take up some space; they take time to be downvoted enough to be hidden; I’m pretty sure they still appear in the sidebar; and the responses to them tend to appear in full, even though these too tend to be valueless. On a more abstract level, I’m worried that such comments influence a collective sense of what the current topic of the site is.

There are intellectual problems other than arguing for the wrong views, and ways of being ban-worthy other than being a troll or spammer. I haven’t read most of the exchanges, but it was certainly my impression that Monkeymind has been communicating in ways that downvotes had made very clear weren’t working for the audience, that he’s been reasoning badly, and that he’s been responding with hostility to downvotes. Are you sure that nobody has been banned for such behavior previously, and that a genuine Rubicon is being crossed here?

If the current system is so perfect that the comments being banned weren’t attracting any attention anyway, is it really a big additional problem for them to be censored?

• This. We should have been done with this several days ago.

• At the risk of exposing myself to a severe dose of negative karma, I have to say I don’t agree with that approach. This is supposed to be a blog devoted to the art of refining human rationality. If we crack down on people too heavily and too early on, before explaining why we disagree with them, I think it defeats the entire purpose of the blog. What would the point be if we just ostracized people who are not already on board with the Less Wrong view of rationality before explaining why we believe that our own approach is the best approach?

• He’s making some interesting points, and he gets extra credit in my view for taking so radical a view while usually remaining reasonable. I find his railing against prediction to be puzzling, but his semantic points and discussion of Ptolemaic explanations have given me a lot to think about.

I also noticed that even some of his friendly, reasoned posts were being downvoted to the same extreme negative levels, which seems unwarranted. He has posted too much without familiarizing himself with the norms here, but he shows sincerity and willingness to learn and adapt. He got a little testy a few times, but he also apologized a lot.

All in all, with a few notable exceptions, it looks like he is getting downvoted mainly for unfamiliarity with LW posting style and for disagreeing with “settled science” (I myself am not too partial to that term). Perhaps also for some unconventional spellings and other idiosyncrasies.

I’m open to being corrected on this, but I think I have read this entire thread and I am pretty sure Monkeymind is not deliberately trolling. High inferential distance feels like trolling so often that it’s almost a forum trope. I myself am enjoying some of his posts and the responses.

I’ll change my mind if he continues with the present posting style, though.

• I am pretty sure Monkeymind is not deliberately trolling

Good intentions don’t always save the day.

• Just tell me what you want, and I’ll comply.

If you prefer not having disagreement, I’ll just have to read and not participate. I can’t simply agree because others think differently. Surely that is not what this is about.

• I can’t simply agree because others think differently.

Actually, you might be able to.

But that’s mostly a technicality; the correct interpretation/​application of the theorem is of some controversy, you’re not obliged to expect us to be rational truthseeking agents, and I don’t think you can rationally expect us to expect you to be a rational truthseeking agent in any event.

• If you interpret his comments in light of his disbelief in prediction, empiricism, and the practical mathematics, then his posts have no value.

• BTW, I will go by whatever the house rules are. I am not here to be argumentative or disagreeable. I am here to learn. I do not argue for the sake of argument. I argue to become Less Wrong!

Originally I thot this was a physics forum. I came to this thread and got into the discussion w/​o reading through the website. My bad! I have tapped out of the thread and will leave it alone. If you must censor me can you please delete all my posts, to be fair. It is hard enough to get people not to take things out of context as it is.

• Are you asking me not to post anywhere in the community or just this thread?

• I’m asking you to not make comments that get downvoted (yes, it’s a confusing hard-to-comply-with rule). Since this currently seems to be most of them, a good heuristic is to almost completely stop commenting and switch to the lurker-mode for at least a few months.

• x

• “To compare, LW contains a few discussions on many-worlds hypothesis versus collapse hypothesis, but those two are mathematically equivalent. In other case, an experiment could be done that decides between them, and someone would probably have done it decades ago.”

Math can, and in the case of QM, must use infinities and 0-dimensional particles which can not exist in reality.

One can describe Hilbert’s Hotel with infinite rooms, but construction of one is impossible. One can mathematically divide in half infinitely, but can not walk halfway to a wall forever. Math can do many things that reality can not.

• Math can, and in the case of QM, must use infinities and 0-dimensional particles which can not exist in reality.

I’m a little confused by this objection to say the least. Could you express your views on the following topics in mathematics, particularly when they are used for real world applications, whether it be physics, computer science or engineering?

1. The use of the “null vector” in linear algebra

2. Limits approaching 0 in calculus

3. Generalizing the rules of 3 dimensional space to represent 4 dimensional space

4. Complex numbers and their various applications, particularly if you think we shouldn’t use the square root of negative one if it has no identifiable physical properties