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Vladimir_M comments on Great Explanations - Less Wrong
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As you note, some things are impossible to explain to an average 13-year-old. By the same principle, some things are impossible to explain while remaining at the "general audience" level. You can produce confusion or fake explanations -- pop-science typically offers some mixture of these two -- but nothing even close to real explanations, let alone actual "clicks."
No, these explanations are far short of what one needs to do actual work in that field. Even the hairy tensor stuff I mentioned is just the beginning.
I wrote this based on my own experience trying to make some sense of relativity. What I sketched is the barest minimum that enabled me to gain anything resembling real insight instead of just confusion and fake explanations.
What I'm trying to say is this.
I do not have a technical understanding of biological evolution. I haven't looked up the equations in population genetics and elsewhere. But even a good pop-sci explanation of evolution from Richard Dawkins does make a positive impact in my understanding of the world. My non-technical understanding of evolution allows me to make more accurate predictions about the world than I would have otherwise. The trick is in making sure I do not over-estimate how well I understand evolution.
Do you actually disagree with this?
Edit: Also, just in case anybody is confused... the meaning of "explanation" in my post "great explanations" differs from the meaning of "explanation" in the phrase "fake explanations." They are two different words that happens to have the same spelling. A "great explanation" is a presentation of a topic that helps readers understand it. The word "explanation" in the sense of "fake explanation" refers to the type of explanation also used in the phrase "scientific explanation."
A good understanding of evolution can be had without any math, unlike physics. There is no math in The Origin of Species, but it's impossible to rewrite any major work of physics since Galileo without math while preserving its essential points.
In any case, what exactly are these more accurate predictions about the world that pop-physics enables you to make? I would be very curious to hear some examples.
My comment about fake explanations applies to any reasonable definition of "explanation." In fact, the points from the "Fake Explanations" article apply perfectly here. If the material from some prominent pop-science book were rearranged into something written in a similar style but in fact completely wrong and nonsensical and signed by an equally high-status author, how many readers of these books would realize that something's wrong?
I will never get a ping time to American servers from my home here in Melbourne of less than the distance times two divided by c.
If I drop a really heavy rock and a somewhat lighter rock from a moderate height there will be only a slight difference in how long they take to fall to the ground.
If I find some stuff that is really, really heavy and leave it in my pocket I will probably die of cancer.
Cars traveling towards me will sound slightly higher in pitch than after they go past me.
If I buy bullets that are designed to travel slower than sound they will probably make less noise than the bullets that go faster than the speed of sound.
If you give me some charts that show how much light of various wavelengths there is coming from two different stars and it so happens that they look really, really similar except that one is kind of 'stretched out' over the 'wavelength' axis I can tell you that the stretched out one is farther away from us.
And, the critical one:
You might believe that my lack of status as a mathematical physicist doesn't give me the right to make claims about Quantum Mechanics implications but the universe doesn't care. I can apply basic principles of rational thinking to filter large swathes of evidence from those who popularize physics and, particularly, the verbal, non-mathematical claims of physicists in order to work out whether or not a specific claim is likely to be correct.
Fair enough. There are indeed many ways in which the folk physics intuition can be improved by internalizing a rule that's simple enough to explain without math. I admit that my question was too aggressive and snarky.
However, I don't think any such simple insights will move you any close to understanding either QM or relativity (let alone more advanced topics such as cosmology or the controversies over QM interpretations), which was the topic of the original dispute. I must also point out that your rules are either from classical physics (and thus reasonably close to the relevant folk physics intuitions) or in the form of entirely opaque rules for which you can't find any justification except for appeal to authority. And I'm certainly not saying that as someone who has "status as a mathematical physicist"; I'm a complete amateur in physics, as I pointed out in an earlier comment. (Also, if you've read my earlier comments on LW, you'll know that I don't put much inherent weight on the official credentials of expertise bestowed by the present academic system.)
Also, regarding the trends in the Copenhagen vs. MW debate, how much of your opinion is based on understanding of the issues involved, and how much on mere perception of the social dynamics in the field?
Then, like Luke, I must observe that your definition of 'understanding' is completely incompatible with mine. Actually, no. I think we've moved beyond that now. You are just wrong.
Look at the first example for a start. That claim is based on understanding of (part of) relativity. But that example was only included coincidentally. May I remind you that the examples you demanded were for physics in general (and, for that matter, that the demand was in response to professed understanding of evolution.)? Space considerations stopped me before I also threw in predictions about "two really good clocks, one of which you fly around really fast!", the fellow who gets into a rocket and outlives his great grandchildren and what happens when you shoot not very many very small things through very small slits.
As I pointed out in my reply to Luke, knowledge of that fact constitutes "understanding of relativity" to the same extent that knowledge of the fact that you can get hurt by sticking your fingers into electrical installations constitutes understanding of electromagnetic theory. It's just a single fact you know in complete isolation, not a fact that is a part of some broader framework for understanding the world.
To build on this particular example, consider that some things like shadows, reflections, etc., can indeed move faster than light. Or, if you just spin on an office chair, in your rest frame the celestial objects are spinning around you way faster than c. Unless you can explain why such motions are consistent with the "no faster than light" principle, you have nothing more than a literally memorized fact that if it might be useful if something could move faster than c, it can't happen. It's a true fact, to be sure, and even a potentially useful one, but still.
The context was about the pop-scientific treatments of modern physics. If you insist on full precision, I will gladly admit that my wording about physics in general was imprecise, since there are indeed simple topics in classical physics where insight can be gained without math, building only on a folk-physics intuition. So please read my statements in their original context.
We aren't talking about the memorization of a simple fact about pings. We are talking about all the understanding you can have about relativity without having memorized a mathematical equation. This can be used to make the prediction that ping times will never be lower than the aforementioned limit.
You asked for examples of predictions about the world that can be made based on understanding physics minus the math. It would be disingenuous in the extreme to then dismiss all examples of predictions about the world given because they are, in fact, mere predictions about the world and therefore could have been memorized without real understanding.
My first prediction: If you (who I believe professed understanding of at least this much understanding of math) and lukeprog were locked in rooms disconnected from the outside world and given the task of answering this question not only would Luke be able to give an explanation, his explanation would be better than yours. You both know enough about physics to answer and Luke is better at explaining things.
My second prediction: There are many students who, in their physics exams, get all the questions that require mathematics correct and who, when encountering a question like this one, can't give an answer. Because not only is knowing the math not strictly necessary to answer this question, it isn't even sufficient.
Additional claim: It has been too long since I studied physics for me to remember all of the mathematics of special relativity. Yet when I did the aforementioned study I also gained a solid grasp of the fundamental principles. With that understanding I could recreate the interesting mathematics from first principles. I am confident of this because I've done it before, just for kicks. Because memorizing the math wasn't enough for me and I wanted to really grasp the science in depth. The way you do that is by knowing the concepts well enough that you could work out the equations for yourself. Because just memorizing them is detail work. (I haven't got a chance in hell of doing this with GR.)
In the various responses you have been given your claim that you can't have any understanding of physics without math has been overwhelmingly refuted. All you are left with is "But that understanding isn't true understanding, true understanding means you remember the math!" To that I reply "No, not all Scotsmen like haggis. You can only tell a true Scotsman by the kilt they are wearing!"
It is time to retreat from a complete rejection of all non-mathematical understanding so that you can express an actually tenable position regarding the limits of how much you can know about physics sans math. Because there really are such limits and I would love to be able to support you in declaring them. But right now you've gone overboard and tried to reject even that understanding which can exist. And that brings you to the realm of the absurd and I just can't support a position which is just obviously factually incorrect.
However, there is indeed a difference between rules memorized in isolation without any additional understanding and, on the other hand, real understanding of physical theories and generating predictions based on them. Just like there's a difference between understanding electromagnetic theory and knowing a few common-knowledge technical facts on how to deal with electrical devices, there is also a difference between understanding relativity and knowing a few facts that follow from it in isolation.
You are now employing a rhetorical tactic where you try to make this obvious and relevant point look like weaseling, but in reality it is a pertinent and adequate response to your example.
This is sheer rhetoric. You latch onto one point I made, completely ignoring the context and making the most extreme uncharitable interpretation of it (one that is in fact bordering on caricature), all for the greatest rhetorical effect. Instead, a rational approach would be to see if there may be some validity behind my point even if its original statement was imprecise, especially since I readily admitted this imprecision on first objection. Not to mention that your own example is largely irrelevant in the original context, which was about lengthy pop-science works purporting to explain whole physical theories to lay audiences, not about isolated examples such as yours.
In any case, if you think the distinction I outlined above is invalid, or that I am applying it incorrectly, please go ahead and explain why you believe that. If you're going to latch onto a caricature of what I wrote while treating the discussion as a rhetorical context, I have no further interest in continuing this exchange.
I think it might be helpful for you to taboo the word "real understanding". It seems like a lot of the disagreement stems from luke and wedrifid being unable to understand what you mean when you use that phrase. To be honest, while I agree with many of your points, I also don't think I understand what "real understanding" is supposed to mean. Perhaps you could restate your original point without use of the word "understanding"?
No one else is arguing that it is sufficient, but they are arguing that it is necessary. In this context, I'm going to make a counter prediction: if one did give a test on SR to physics students just learning about it, the ones who answer the chair question correctly will be a proper subset of the ones who can do the mathematical manipulation.
In the more restricted context of highschool calculus or more basic physics this is (from my experience both teaching and tutoring) very much the case. There are students who say things like "I can't do the math but I understand the concepts" and this just nonsense. The ones who answer the conceptual questions correctly are almost always those who can do the math. There may be kids who can do the formal manipulation and can't connect to it conceptually but there's almost no one who can't handle the symbol pushing who can answer the conceptual level questions. They are too interrelated.
Why do the they believe what they believe? The simplest two explanations I can think of is that they are mistaken about their grasp on the concepts (when you ask them conceptual-level questions, they answer incorrectly), or they are mistaken about their inability to do the math (they feel insecure before quantitative tests, but score high). Is one of these the case?
Question: If the world were wiped out tomorrow leaving a few people and you were the only survivor with any minimal scientific training, could you on your own reconstruct special relativity? If the answer to this is "no" then you don't understand it.
Note that by this standard I don't understand QM and I really don't understand GR and I'm a math grad student. It is ok to say that one doesn't understand things.
Yes. I already declared this, in a comment you replied to no less.
Funny you should mention that. I spent years working in IT, and this knowledge was actually useful once. I tried to ping a DNS router in Europe (I forget where) from California, and it came back in 1ms and I thought "Ummmmmm... no. You lie." It turned out one of the smart switches on the local network was fucked up and was somehow returning all pings itself.
Behold! Even a pop-sci understanding of physics controlled my anticipations in a way that was useful for accomplishing goals in the world.
That is pretty awesome, but I also don't think it's necessary to think about light speed to solve that problem. Anyone who spends a lot of time debugging networking problems knows that 1ms is unreasonably fast for any communication with a machine more than a couple router hops away, even if it's physically nearby.
I see that this is getting upvoted, but your example sounds like someone who realizes that a device doesn't work because it's not plugged in, and then makes a self-satisfied comment that his knowledge of electromagnetic theory usefully controlled his anticipations in this situation.
In other words, it's about simple conventional nuts-and-bolts technical knowledge, not an improvement on such knowledge brought by more advanced understanding of anything. There's no way someone who works in network administration wouldn't know that a "<1ms" ping coming from around the world is anomalous.
Actually, yes: I think this is correct.
But, I think I would have noticed something was wrong even if I hadn't worked in IT before. But I'm not certain of that.
This great story is related.
Typically, when someone's car breaks, they don't bring it to church, they bring it to a mechanic. In the distant past, people probably brought the equivalent of their cars (when broken) to the equivalent of church. This is progress. I could be wrong, but I think Luke wants more of this, in more domains. I personally think this is less a question of the right explanation, and more a question of daily necessity. If you need physics every day, you'll have fewer wrong ideas about it. But who needs physics every day? Almost no one.
(And yes, some people probably still bring their broken cars to church.)
EDIT: Not everybody wants to be or has the talent to be a "mechanic," but that doesn't matter. What matters is that people associate "broken car" either with "person who can fix broken car" or "reliable knowledge about how cars work" instead of "sky father."