"I understand nothing"

By Sean Carroll | March 6, 2009 11:26 am

From The Tao of Physics to What the Bleep Do We Know?, quantum mechanics has been a favorite target for wildly misguided cultural appropriations. That’s hardly surprising; quantum mechanics is hard, and not many physicists understand it at a deep level. The only interesting argument is whether “not many” in that sentence should be replaced by “no.”

Yesterday I stumbled across two invocations of quantum mechanics in very different contexts. First, via 3quarksdaily, historian John Lukacs muses on the centrality of our nature as human beings to our ability to apprehend and understand the world.

All of this happened during and after three-quarters of a century when physicists, inventing and dependent on more and more powerful machines, have found more and more smaller and smaller particles of matter, affixing them with all kinds of names. Until now, well into the 21st century, it is (or should be) more and more likely that not only A Basic Theory of Everything but also the smallest Basic Unit of Matter will and can never be found. Why? Because these particles are produced by scientists, human beings themselves.

Every piece of matter—just as every number—is endlessly, infinitely divisible because of the human mind. Some scientists will admit this. Others won’t.

It goes on like that at great length; it was hard to choose a representative excerpt. Basically, Lukacs is making a mistake resembling that which I accused Paul Davies of some time back — demanding that properties of as-yet-known physical theories conform to some cherished metaphysical presuppositions. In reality, the fact that scientists built the apparatuses that produce elementary particles doesn’t tell us anything at all about whether a Theory of Everything is an attainable goal. It may or may not be, but our status as conscious human beings doesn’t have anything to say about it.

And then, via Cynical-C, we find Roger Ebert reviewing Watchmen:

So let’s ask what we understand about quantum mechanics. We’ll start with me. I understand nothing.

Oh, I’ve read a lot about it. Here is what I think I know: At a basic level, the universe is composed of infinitesimal bits, I think they’re called strings, which seem to transcend our ideas about space and time. One of these bits can be in two places at once, or, if two bits are at a distance, can somehow communicate with one another. Now I have just looked it all up in Wikipedia, and find that not only don’t I understand quantum mechanics, I don’t understand the article either. So never mind. Let’s just say my notions are close to the general popular delusions about the subject, and those are what Dr. Manhattan understands.

Let’s see: despite the name “quantum,” it’s not really right to think of quantum mechanics as based on individual “bits.” But it’s true that fields resolve themselves into particles under careful observation, so that’s an excusable confusion. “Strings” have nothing to do with it, a consequence of mixing up different topics in the pop-science domain. “Somehow communicate with each other” refers to entanglement — widely-separated entangled particles don’t really communicate, but that’s certainly our fault as scientists and communicators, since we keep saying that they do.

There are two major differences between Lukacs’s discourse on quantum mechanics and Ebert’s. First, Lukacs is much more subtle, intricately weaving concepts from modern physics into a thesis concerning the role of history in human affairs. (Still completely wrong, of course.) But second and more importantly, Ebert admits he has no idea what he’s talking about, and goes to look things up on Wikipedia; Lukacs, in contrast, flaunts his misunderstanding, waving it around as proof of his erudition. Score one for the non-academics.

(And there’s no justification for scientists sneering at historians in general on this score; if I had a nickel for every time a physicist flung around concepts like “falsifiability” or “postmodernism” without knowing what was going on, I could rescue the American banking system all by myself.)

What I really found interesting was that Ebert, after giving up on Wikipedia — and rightfully so, their physics articles are uniformly useless for someone approaching the ideas as an outsider — turned next to YouTube for edification! He includes a few clips that try to say something helpful about quantum mechanics. I wonder if that’s the wave of the future. It gave me the idea of making a set of very short videos, each of which would succinctly explain one scientific idea. Making a two-minute video would take less time than writing a decent blog post. (Right?)

CATEGORIZED UNDER: Science and Society
  • nobody

    Hi Sean,
    About your comment regarding that the physics articles on Wikipedia are uniformly useless for someone approaching the ideas as an outsider, I think you’re flat out wrong… and I’ll explain why:

    1) I’ve talked with many people who are not physicists but have understood a couple of things by reading these articles

    2) It depends on how you define “useless”. If you mean that an outsider will reading a Field Theory article and will be able to calculate some quantity himself, then I agree they are useless but remember a Wikipedia article cannot substitute a book. If on the other hand you mean that he won’t even grasp the basics then I disagree as many physics/astronomy articles are Featured (which are chosen by laymen not scientist) and this means that they are of the highest quality.

    However, I agree that some articles could be better and whenever I’ve come across one that needs corrections I do my best to fix it.


    PS FYI I’m a physicist as well but for reasons of self preservation I’ll remain anonymous :)

  • Chuck

    IANA Physicist and I welcome your two minute science videos. I understand very little of what happens in physics research today, despite always having a healthy interest in science in general.

    Bring on the video!

  • Matt

    I’m not surprised about Roger Ebert. If you read his reviews with regularity, you’ll notice that he is very much the ideal lay man in regards to science. His knowledge of quantum mechanics, as he himself admits, is lacking, but he’s also one of the few movie critics who knows enough science to chide movies for scientific unrealism. Find a review of a sci-fi movie from him, and you’ll see. Probably most importantly, he approaches science from an underlying position of respect, of humble reverence. It’s that basic respect and humility that is lacking from people like Lukacs.

    And, for the record, there are some of us who do understand quantum mechanics, and not just at the operational level of symbolic manipulation. So the answer to your question, whether “not many” should be replaced with “no,” is “not many.” People who say differently are either covering for their own insecurity, or arrogantly want to present to what they do as being esoteric and beyond the capacity of mere mortals.

  • JGS

    Hi Sean,

    I love the idea of your videos, and would very much like to see what you come up with. I am most definitely not a physicist in any way, but enjoy trying to grapple with some of these ideas (and as a teacher of philosophy they sometimes become germaine). Many of my students are much more profoundly influenced by “What the Bleep” and its ilk than any science class they have had. It would be great to have a few videos to point them to that actually made sense.

    BTW- I link to your blog from my class website- many of my students are reading your blog as well!


  • Michael

    Just my two cents here but I think the two-minute videos would be a great idea, although perhaps five-minute or even hour long videos would be better. I was thinking today about how much of the difficulty I’ve had in the past understanding quantum mechanics stemmed more from the esoteric nature of the presentation in textbooks rather than the esoteric nature of the subject itself. I think there is a fine line between communicating material in a way that younger generations can understand and doing so in a way that is so overly colloquial that it peaks out in terms of comprehensibility and then grows dated after a while. For example, in my opinion the success of your GR textbook is largely due to this, while Wheeler’s falls in the realm of the latter and Landau’s is the polar opposite.

    Anyways on the subject of youtube, I always used to fall asleep watching reruns of favorite television shows on my computer to lull me to sleep. These days I’ve taken to falling asleep to Susskinds enormous collection of physics lectures on youtube in order to make the act of falling asleep a bit more educational. I wish there was more stuff like that available at a level more sophisticated than the Teaching Company videos.

  • http://backreaction.blogspot.com/ Bee

    I find it really disturbing how many people there are who believe they have something to say about a topic they evidently know next to nothing about. I like to refer to this as “The Illusion of Knowledge”

  • http://www.scienceloaf.com Headloafer

    I like the video idea, but it will be a difficult task. According to the National Center for Voice and Speech, the average rate of spoken English is ~150 words per minute. With so few words to play with you may have to break down the scientific ideas into smaller and smaller chunks. Then you run the risk that somebody says “Every [scientific idea]—just as every number—is endlessly, infinitely divisible because of the human mind.”

  • MedallionOfFerret

    While reading Ebert’s quote in your post I assumed it was a self-satire–the Ebert knows much better, and was playing it for laughs because he knows he doesn’t understand it well enough to pontificate. If you read the article–which is about the movie Watchman, he spends a lot of time poking fun at the movie’s assumptions, too.

    Richard Feynman: “I think it is safe to say that no one understands quantum mechanics. Do not keep saying to yourself, if you can possibly avoid it, “But how can it be like that?” because you will go “down the drain” into a blind alley from which nobody has yet escaped. Nobody knows how it can be like that.”

    Sometimes physicists–even the most percipient of them–have the same problem in understanding movie critics, too.

  • MP

    The YouTube videos are a fantastic idea. You know that there are probably thousands of crackpot videos on YouTube now “explaining” a what-the-bleep version of Quantum Mechanics, so why not some legitimate ones?

    Also, Roger Ebert is actually a very intelligent person. I get the impression that he dumbed down his own understanding of QM to give us an idea of what the public perception is. See, he is able to write so that the general public can understand him, a skill which takes much greater intelligence than obfuscating your misunderstandings with academic-speak.

    Funny, I would describe Lukacs position as being very postmodern, and I checked here to make sure I was right: http://en.wikipedia.org/wiki/Postmodernism

  • http://blogs.discovermagazine.com/cosmicvariance/sean/ Sean

    Just to be clear: there’s no sense in which I was criticizing Ebert. He wants to be able to talk about quantum mechanics rather than consign it to the file of impossibly difficult ideas, which is good, and he admits that he doesn’t understand it very well, which is even better. An admirable stance all around. It’s the job of scientists and educators to make these ideas clear to the widest possible audience of interested non-experts.

  • Anon

    Two minute videos? That’d be great. Given the readership of this blog, rest assured, there’d be a huge audience for the videos AND a huge responsibility for the bloggers here. But the objective would be best served with plenty of animations for an audience with high-school physics knowledge, but a deep interest in the subject, rather than lecture style presentations. You could begin with a video on what Quantum mechanics is NOT and get that out of the way for the rest of us who confuse it with string theory.

    Given the credentials of the bloggers here, you WILL be quoted, linked and otherwise exposed to a larger audience that prefers their science in cartoons. Good luck with this.

  • Anon

    And oh yeah, Ebert rocks.

  • Marcos

    Hi Sean,

    I’d never heard from Lukacs before, so I would not rush in tagging him, but if he keeps writing like that he could get tenured at the “Deepak Chopra Institute for Crackpot Theories Using QM.” I think the videos are a good idea, in that area I also enjoy the “explain it in 60 seconds” section of Symmetry mag.


  • Sili

    Making a two-minute video would take less time than writing a decent blog post. (Right?)

    No. But that doesn’t mean you shouldn’t do it. Might want to ask Phil first why he stopped doinghis ‘tubes with the Squishy Brain of SCIENCE!.

    Every piece of matter—just as every number—is endlessly, infinitely divisible because of the human mind. Some scientists will admit this. Others won’t.

    So according to Lukacs, no matter how often you cut the cheese, you’ll still end up with a piece of cheese, only smaller?

    Democritos must be spinning in his grave.

  • Amos Kenigsberg (Discover Web Editor)

    Funny you mention this two-minute-explanation idea, Sean—DISCOVER has done something very much like that: a user-generated video contest series called Science in Two Minutes or Less. The first contest was String Theory in Two Minutes or Less, and we got some really great entries: http://discovermagazine.com/twominutesorless

    We’re just about to start another entry in the contest series: Evolution in Two Minutes or Less. From the ad for the contest: “If you can show even the most hard-headed creationist that Darwin was right, then you should enter your submission in DISCOVERmagazine.com’s next iteration of the “Two Minutes or Less” video contest.”

    The submission page will go live on the site soon.

    [Update 9 March: I updated the link, which was previously broken. Stupid WordPress!]

  • Brian

    Sean: an excellent post. Your contrast of Lukacs and Ebert is apt and worth noting.

  • http://www.gregegan.net/ Greg Egan

    One additional problem for quantum mechanics is that there are extremely reputable and intelligent physicists who have apparently thought long and hard about the subject and reached different conclusions about its ontology to others in the same category. So at some point, a populariser has to choose between coming down on the side of David Deutsch, or of Asher Peres, or of trying to explain that for all we know (or at least for all I know) either one of them might be right. It’s not an insurmountable problem, but it is an additional hurdle for lay people trying to get to grips with what’s going on.

  • James Latham

    The video idea is a good one. On the other hand you could do some more blogginghead.tv discussions with David Albert, interaction can make it more interesting and you can get the different perspectives on the issues. Could I suggest a series of ten bloggingheads videos starting out with with the historical basis for thinking up quantum mechanics passign through Copenhagen, recounts some of the experimental results (which fundamentally drive the theory) and ending with many worlds and roger penrose’s theories, etc.

  • gopher65

    The major physics articles on Wikipedia are fairly well written, but once you start to get into the subpages they turn into nothing more than a giant ramble with a few equations tossed in.

    I’ve read Wikipedia physics articles on topics that I was already fairly familiar with, and been so thoroughly confused that I had to go look up what I already knew in a book, just to clarify.

    Granted, Britannica isn’t any better. There is only so much you can say in a couple thousand words. I mean, it isn’t like they can write an entire John Gribbin or Phil Plait book and make that an article. It’s simply an inherent limitation to the encyclopedic format. And that is why there are other Wikimedia projects besides Wikipedia;). There are just some things that can’t be done with an encyclopedia.

  • Mr Paul

    Video idea is great! For a good example, check out MarketPlace.org’s Whiteboard series (http://marketplace.publicradio.org/videos/whiteboard/)

  • Jean-Paul Billon

    Well, some weeks ago in France I had a dispute in a well known French newspaper (Liberation) website with a physicists from the French national research center (CNRS) who was writing that Quantum mechanics is as obscure and magical than astrology. He was citing Feynman to support his claims that quantum physics was a mystery that was leading people into a kind of mystical fuzzy realm that Science should not allow. My guess is that Feynman, who is so respected on both sides of the Atlantic Ocean, is partly responsible of this kind of anti-scientific reaction from practicing scientists themselves. If one wants to get through the basis of Quantum mechanics, there is the wonderful introduction in the book of Landau and Lifshitz about classical quantum mechanics that provides a deep understanding of the Copenhagen position, or the book about the many-world interpretation published by Princeton university. Laymen newspaper people can be rightly confused when scientists are not providing them with the right argumentation and prefer sensationalist declaration to keep the light on them. I do not say that Quantum mechanics is fully understood, as the bottom of this theory is that we cannot understand what’s going on in the realm of particle physics because our cognitive capabilities have been designed to cope with our macroscopic macro-world perceptions. That leads to some insatisfaction that the afficionados of Bohm/de Broglie causal interpretation are still keeping alive. Whatever, current physics is far from these basic questions and really embedded in much narrower questions, and that is not easy to make that understood by laymen newspaper people, which is the true difficulty of contemporary physics to become understood by non-specialized, and even specialized, people.

  • http://scienceblogs.com/sunclipse/ Blake Stacey

    Hey, I was one bureaucratic technicality shy of getting a literature degree to go along with my physics one, on account of all the comparative-media-studies electives I took. I earned my right to gripe about “postmodernism”, goddammit!

    Basically, Lukacs is making a mistake resembling that which I accused Paul Davies of some time back — demanding that properties of as-yet-known physical theories conform to some cherished metaphysical presuppositions.

    Funnily enough, just this morning I was sent a link to a typical “fractured ceramic” website, in the “quantum mechanics is wrong” genre. This was basically his stance on the EPR experiment: to the inventor of “Super Relativity”, that an explanation works doesn’t matter. Because it’s so darn unintuitive, it’s farcical, if not outright sinful.

    Also: you never appreciate the value of the abstract-up-front organization of scientific journal articles until you’ve seen the alternative.

    (Someday, I’d like to put the people who proclaim that “quantum physics is a fraud and scientists are conspiring to hide the truth” in a confined space with the ones who tell us “homeopathy works because of quantum physics and scientists are conspiring to hide the truth”. We could borrow a box from Schrödinger and have great fun making bets on who’ll come out.)

  • http://scienceblogs.com/sunclipse/ Blake Stacey

    Oh, I forgot to mention — The American Scholar has published serious misunderstandings of modern physics before.

  • Low Math, Meekly Interacting

    On the one hand I like the idea, but on the other, when it comes to even approaching a feeling of comprehension of such subjects, sometimes I need to read it. And re-read it. And re-re-read it. Then again, it’s hard to beat a visual for getting some difficult points across. I really enjoyed watching Feynman perform his dry run of “QED” in New Zealand, even though I’d already read the book. I’d say choose the video subject judiciously, keep a whiteboard handy to dash off helpful illustrations, and it could be a great way to augment blog posts.

  • Pingback: Friday Evening Quips (6 March 2009) « blueollie()

  • http://scienceblogs.com/sunclipse/ Blake Stacey

    Making a two-minute video would take less time than writing a decent blog post. (Right?)

    Phil Plait did a pretty impressive job with his “Q&BA” series. That might be a model worth emulating.

  • Chris W.

    Blake, thanks for that link. The excerpt from Brian Boyd’s essay (in your comment) bolsters my faith that there remain many intelligent and careful thinkers in the humanities, notwithstanding the corrosive effects of certain mind-numbing fads (which seem to have largely run their course in recent years).

  • Sean

    “if I had a nickel for every time a physicist flung around concepts like “falsifiability” or “postmodernism” without knowing what was going on, I could rescue the American banking system all by myself.”

    You may understand quantum mechanics, but I am suddenly very skeptical of your ability to do basic division. :)

  • Oded

    I’ve recently given up trying to understand quantum mechanics properly through wikipedia and youtube and have turned to this instead – http://www.youtube.com/profile?user=stanforduniversity&view=playlists

    Stanford university lectures by Leonard Susskind

    I’m halfway through the quantum mechanics course, and so far so good…

  • Pieter Kok

    Blake, that’s a great blog name: Fractured Ceramics.

  • David Goss

    Dear Readers; Such videos basically already exist. Indeed, for about a year now the
    Journal of Number Theory has been publishing on youtube “video abstracts” for some of the
    papers that are accepted for publication. (We leave it to the author(s) at the moment whether they create such a video.) The idea is that these are going to be archived with the
    paper so that readers in 50 years can see and hear the speaker. If these are done enough you will
    be able to follow the speaker through his/her career this way.
    We also are putting these on youtube (besides the server of the publisher) and you can
    f ind them at
    The video by Alain Connes found there is a brilliant example of the power of these videos.
    David Goss

  • Zwirko
  • jb

    “And there’s no justification for scientists sneering at historians in general on this score; if I had a nickel for every time a physicist flung around concepts like “falsifiability” or “postmodernism” without knowing what was going on, I could rescue the American banking system all by myself.”

    I’d like to see some cites here. I’ve seen you chide scientists before about their “naive” philosophical ideas. Heck, I believe your post defending Derrida at the time of his death may be the first blog post I ever read. So, how do you think physicists misunderstand falsifiability? And how in any way does this compare to the near total misunderstanding of things like the Heisenberg uncertainty principle or Godel’s incompleteness theorem among the humanities set? Do you think you understand “falsifiability” and “postmodernism” in a way that most other physicists don’t, or do you merely assume the typical characterization of them is wrong? Do you think working scientists would actually benefit from knowing these things or do you just wish we’d all stop knocking Bruno Latour so you don’t feel obligated to apologize for your fellow physicists to Berube?

  • http://blogs.discovermagazine.com/cosmicvariance/sean/ Sean

    jb– I don’t claim to be an expert in these things myself, nor do I know how to compare the relative amount of misunderstanding between two fields. Nor do I think that you necessarily become a better scientist by studying the history and philosophy of science.

    But I do think that the default assumption of experts in field X when approaching field Y should be one of respect — imagining that the true experts in that other field are likely to be smart people who have thought hard about very difficult problems. Prolonged exposure may force one to modify the default assumption, but it’s the proper place to start. If something seems ridiculous on first blush, your initial assumption should be that you don’t understand it, not that the people in field Y are all idiots. Likewise, when you want to appropriate some handy concept for you own purposed, it’s a good idea to keep in mind that there are probably a lot of subtleties and caveats involved, and you should probably be careful.

    Very few scientists would disagree with these recommendations, if they were given to humanities professors talking about science; I think they are equally sensible when scientists want to talk about the humanities.

  • jb

    I agree that a default attitude of respect is appropriate, although when say a historian of science is discussing science I don’t think that it is necessarily obvious that they are the expert and that actual scientists are evaluating their work from a position of ignorance, but in fact quite the opposite. The question though is how much scientifically ignorant pap like that which you quoted from John Lukas above must one endure before harboring suspicions that maybe this kind ignorance may in fact be endemic to certain areas of research? Certainly people like Sokal and Bricmount (or Levitt and Gross before them) have made at least a case for this.
    My main objection to your post though, was your implication that scientists are just as ignorant of things outside of their expertise (or it would have to be inside their expertise to really be fully equivalent since Lukas is making ignorant claims about science as part of work in HIS discipline). I would bet you object to this kind of everybody’s equally guilty, pox on both houses, etc. kind of discourse when discussing Republican smear tactics for instance. Why do you indulge in it here?

  • http://bafoontecha.com Sumanth Peddamatham

    Hey Sean,

    A few months ago, I had a similar idea about teaching through visuals. I’m in the process of creating short clips to explain Fourier Analysis and Convolution; still getting the hang of After Effects.

    Early betas are up right now, your readers might be interested:

    Fourier Analysis: http://bafoontecha.com/2008/12/11/a-visual-guide-to-fourier-transforms/
    Convolution: http://bafoontecha.com/2009/01/25/on-convolution-and-other-things-you-think-you-dont-know/

  • Spiv

    hm…seems to me you’d have to hear a physicist say “falsafiability,” or “postmodern” about twice a second for 12 hours a day every day of your life (guessing age) to make that nickel argument. That’s assuming 700bil was really enough. Which is a bad assumption.

  • Winter Solstice Man

    As a New York Times book critic once said about Buddhism, it does not take a great deal of intelligence to empty one’s mind.

    Reading reviews on Watchmen has finally convinced me that most film critics are clueless and only interested in promoting themselves. Ebert is a bit better than most in this category, though, but most of them know about as much science as did a recent former US President.

  • Peter Shor

    The problem with saying that physicists don’t really understand quantum mechanics is that people start saying “Well, since nobody really understands quantum mechanics, maybe at the bottom level there are really purple unicorns ….” We may not really, really, truly understand quantum mechanics, but we understand enough to know that we don’t need purple unicorns.

    So purple unicorns are not a realistic example, but I’ve had this essentially this conversation with people about faster-than-light communication, and about reasons for quantum computers being fundamentally impossible.

    Journalists love to say that scientists don’t understand things. As scientists, I don’t think we should make the claim that we completely understand quantum mechanics (especially when we don’t completely understand how it fits together with general relativity), but I don’t know what we should say instead, though. Any suggestions?

  • Igor Khavkine

    I don’t see a problem with claiming an understanding of quantum mechanics. Perhaps this understanding is not “complete” and “true”, but to be honest I don’t understand what that would even mean.

    To journalists, one can say, like for any other topic, that there are those who do not understand quantum mechanics because they’ve not studied it sufficiently, but that there are also those who’ve studied it and do understand it. However, part of the latter group, perhaps for historical reasons or perhaps out of personal modesty, don’t admit to it. Notably, Feynman, whose famous quote about nobody understanding quantum mechanics often gets brought up in these discussions, belonged to that subcategory, among other names like Einstein, Bell, Bohm, etc. The much bigger problem is posed by those who claim an understanding without any study. And, unfortunately, there’s no shortage of them.

    As a short sound bite nugget, I would offer in the most facetious of tones:

    Screw Feynman! Anyone who works at it can understand quantum mechanics.

    Though, perhaps, it comes off as a bit too crass for general consumption. :-)

  • http://blogs.discovermagazine.com/cosmicvariance/sean/ Sean

    Peter, I absolutely agree. My default approach is to tell the truth: there are things that we don’t understand about quantum mechanics. Also, there are things that we do understand. “We don’t know everything” is not a license to ignore the things we certainly do know.

    However, I agree that it would be nice to have a better way of conveying this state of tentative knowledge more concisely and accurately. Open to ideas on that score. I suspect there may not be a simple solution, just because the concept is very subtle.

    Maybe analogies are helpful: “We don’t know, with mathematical certainty, what would be the perfect play to call in any particular situation during a football game. But we’re pretty sure that punting on first down is a bad idea.”

  • Peter Shor

    Hi Sean,

    I like your analogy!


  • CJA

    I didn’t see any metaphysical presuppositions driving Lukac’s argument (maybe in the last few paragraphs, where he strays off and makes a big point he never really tried to justify). As I understood it, Lukacs is using his rudimentary understanding of quantum mechanics to make an epistemological, or even logical, point about a Theory of Everthing. Not metaphysical, and much more relevant to an actual discourse on science. In short, he’s talking about the inability to prove a Theory of Everything, not the inability of the world to be a certain way. than However, I am also guilty of trying to make sense of Lukac’s argument, even where it does not quite make sense, so I might be misinterpreting him.

    Lukacs clearly starts with some picture of Heisenberg Uncertainty–we can’t know the mass and velocity of a particle precisely as they are because the knowledge requires observation, and observation alters the way things are. Fair enough. Somewhere he makes a big jump from that to saying we don’t even know if all of these subatomic particles exist because our evidence of them is also based on observation using human machines (not sure if actually means we don’t know that the subatomic particles exist, but that seems close). Et. cetera et. cetera…. any theory of everything at best purports to tell us the way the world probably works. The inability to have a theory of everything is therefore an epistemological constraint of the Uncertainty principle–which I guess we will assume to be true without any doubt. Depending on the level of certainty/probability you require from a quantum theory of everything, he might even have a point there.

    He adds to that a point that scientific knowledge is human knowledge and therefore constrained by our own capacity to understand and interpret the world. It doesn’t mean that the world does not operate according to unified laws, it just means that we as humans will never understand those laws. Now, at first look that is dependent on metaphysical assumptions. After all, there is no basic principle that implies that the laws of physics must be hard to understand. Per Sean’s commentary, we haven’t discovered those laws yet, so lets not rule out the idea that they could be simple.

    But some of his discussion suggests that he making a more analytical, and less metaphysical claim about the relationship between the theory of everything and human intellectual capacity. He basically assumes a theory requires a finite system of particles (or fields). I assume that Lukacs doesn’t really understand the finer points of what he is talking about regarding splitting atoms into smaller and smaller pieces. But also, we can’t keep positing and infinite set of new entities to fit into our theory of everything, or else no finite being will ever understand said theory.

    Lukacs point here is actually kind of interesting, though by no means something I am ready to accept without question: human language and mathematics inherently involves terms which are infinitely divisible, a theory of everything inherently requires particles which are not infinitely divisible, therefore it is impossible for a human to understand a theory of everything that is written in human language/math.

    That just sounds wrong–of course I am capable of understanding discrete items; in fact, I primarily observe the universe as a system of discrete macroscopic object. But at least that is an analytical/linquistic argument against the theory of everything, not metaphysical. Again there is a huge difference. Metaphysical arguments are just anti-science in a sense (not completely: a cosmologist is happy to know that our universe can’t be one which violates the grandfather paradox, or other logical impossibilities; we do want our laws to describe a world that can actually exist). The analytic argument, if it could be made to sound little less weird, I’d be interested in thinking about twice.

  • http://www.users.bigpond.com/pmurray Paul Murray

    after giving up on Wikipedia — and rightfully so, their physics articles are uniformly useless for someone approaching the ideas as an outsider …

    No kidding. The general maths articles are as bad – it’s like someone has gone through and removed anything that might be useful to a newbie on the basis that introductory material is “not encyclopedic” enough. The pages just go round and around.


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About Sean Carroll

Sean Carroll is a Senior Research Associate in the Department of Physics at the California Institute of Technology. His research interests include theoretical aspects of cosmology, field theory, and gravitation. His most recent book is The Particle at the End of the Universe, about the Large Hadron Collider and the search for the Higgs boson. Here are some of his favorite blog posts, home page, and email: carroll [at] cosmicvariance.com .


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