One Last Stab

I’ve been too busy to contribute much to the laws of physics discussion, and now I’m about to hop on a plane to bluegrass country. But I am sincerely seeking the best way to make this point clear, so one more quick try. And I do appreciate the back-and-forth thus far; sometimes frustrating, but certainly very useful to me.

If you were to ask a contemporary scientist why a table is solid, they would give you an explanation that comes down to the properties of the molecules of which it is made, which in turn reflect a combination of the size of the atoms as determined by quantum mechanics, and the electrostatic interaction between those atoms. If you were to ask why the Sun shines, you would get a story in terms of protons and neutrons fusing and releasing energy. If you were to ask what happens when a person flexes a muscle, you would hear about signals sent through nerves by the transmission of ions across electromagnetic potentials and various chemical interactions.

And so on with innumerable other questions about how everyday phenomena work. In every single case, the basic underlying story (if that happens to be what you’re interested in, and again there are plenty of other interesting things out there) would involve the particles of the Standard Model, interacting through electromagnetism, gravity, and the nuclear forces, according to the principles of quantum mechanics and general relativity.

One hundred years ago, you would not have heard that story, because it hadn’t yet been put together.

But — here’s the important part — one thousand years from now, you will still hear precisely that same story.

There might be new layers underneath, but it won’t be necessary to refer to them to give a sufficient answer to the original question. There will certainly be much greater understanding of the collective behavior of these underlying particles and forces, which is where most of the great work in modern science is being done. And hopefully there will be a deeper story about why we have the laws we do, how gravity and quantum mechanics play together, how best to interpret quantum mechanics, and so on.

What there won’t be is some dramatic paradigm shift that says “Oops, sorry about those electrons and protons and neutrons, we found that they don’t really exist. Now it’s zylbots all the way down.” Nor will we have discovered new fundamental particles and forces that are crucial to telling the story of everyday phenomena. If those existed, we would have found them by now. The view of electrons and protons and neutrons interacting through the Standard Model and gravity will stay with us forever — added to and better understood, but never replaced or drastically modified.

I’m not actually trying to say something controversial. I think it is pretty unambiguously correct, once I actually say it clearly. But it’s something I think is not as widely appreciated as it really should be.

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60 Responses to One Last Stab

  1. ted says:

    Right Sean, but this is not your original argument. Before you argued that there were things in everyday life (let’s say 120) years ago that blatantly contradicted current Newtonian theory. Now you are saying that modern theories have more explanatory power – well duh!

    You say that we will have the same explanations 1000 years from now. Could be, but that kind of prediction is pretty cheap.

  2. ted says:

    And ditto what Cosmo and Dick F said.

  3. Cosmonut says:

    @Dreamer:
    Is it mere coincidence that you are making the same argument for “something else” as the ID/Creationists do about the exact same two phenomena?
    —————

    Don’t know if its mere coincidence since the arguments are quite different.

    From what I know of the silly science/ religion wars going on in the US, the ID position is that scientific theory CAN’T explain such and such phenomenon, and hence it must be Jehovah at work.
    (although any person with sense can see that its actually Shiva :))

    So, in terms of Sean’s post, they claim to have the sort of counterexamples to phenomena explained by science, that were readily available 100 years back.

    If those claims really held up, that would cause a lot of excitement, I’m sure.
    But even if they did, the “Its Jehovah !” conclusion is not immediate at all.
    (The first step would surely be, “Its new physics !”)

    My argument was more on the lines of “How sure can we be that the known physics DOES explain very complex phenomena, given how tough it is to model the systems ?”.

    Anyway, Sean has grasped my point very well, so see his reply @24.

  4. Marty says:

    If our best physical theories rely on postulates, does the fact that we formulate those postulates mean we understand what they postulate?

    One of the most ordinary attributes of the macroscopic world, and one that any person (educated or not) can observe, is that three spatial dimensions are sufficient to describe the relative positions of macroscopic objects. General relativity postulates a smooth differentiable manifold on which the metric can be determined if we know the stress-energy tensor over all of spacetime. The metric will have signature -+++, by assumption (and of course, because that is what agrees with observation). Since we have postulated 3 spatial dimensions, one time dimension, and a Lorentzian signature, does that mean we “understand” those facts? Sure, we observe that those postulates are apparently correct, at least macroscopically, but to say we “understand” those facts is contrary to what I think of as understanding.

    I think similar comments can be made about other parameters and postulates of our theories — do we understand them because we observe them, in the same sense that we understand gravity from general relativity?

  5. wolfgang says:

    Once again Sean states the obvious (“it is close to impossible to find contradictions to the Standard Model with kitchen table experiments”) in such a way as to maximize opposition in comments to his blog post.
    Maybe Hiatus is not always such a bad thing 😎

  6. Boaz says:

    Dreamer, in 14, emphasizes the quote about molecules interacting via the standard model.
    with Sean’s added caveat, “added to and better understood”.
    That seems important to add the caveat, because in a chemistry class, you really don’t study a Helium atom as a set of quantum fields, which are really wave functionals. One uses some kind of semi-classical approximation. In other words, one never really does the reduction to the lower level theory. Assumedly, the string theorists would like to study helium as string states.
    The standard model seems to be good for calculating S matrix elements, etc. so that we can compute the effects of collisions in the LHC and other colliders. But using it to describe chemistry seems quite hard. I wouldn’t go as far as to say its impossible, but I think that we cross domains from one theory to another with somewhat loose language. (I’m not clear whether the interpretation of wave functionals for bound states is really totally understood. Maybe I’m wrong.) Whether this way of talking about the relationships between different levels of phenomena will stick with us for 1000 years is not totally obvious to me.
    But I think its good for people to continue trying to connect these theories together and to do the reductions and connections as well as we can. Maybe we will find new interesting things in these attempts to formalize it more!

  7. Ryan says:

    I have two questions I don’t think we have a sufficient understanding of the universe to answer;

    1) What generates the coherent behavior of large flocks of birds
    2) What is the nature of the process which generates (or embodies) consciousness

    My point isn’t to ask for specific answers, but to point out that I think there is a class of problem science is just beginning to consider; the issue of emergent dynamics and the behavior of partially chaotic systems.

    It’s true that we know why the birds are ‘solid’ and that the brain uses electrical impulses somehow, but this isn’t the same as having a rigorous understanding of the qualitative difference between a thousand birds flying randomly and a thousand birds making instantaneous and coordinated decisions about which direction to fly in.

  8. Gordon says:

    1. I would postulate that it is like an array of cellular automata and a local phenomenon and is not instantaneous but seems so. Each bird reacts to the bird in front of it or in its visual field, so if the bird in front turns to the left, it does, and the effect ripples almost instantaneously through the flock.

  9. Gordon says:

    2. Not known yet. Christof Koch is working on it:
    http://www.amazon.ca/Quest-Consciousness-Neurobiological-Approach/dp/1936221047/ref=sr_1_3?s=books&ie=UTF8&qid=1286039057&sr=1-3

    The Quest for Consciousness, a Neurobiological
    Approach

  10. felix says:

    Completely explaining everyday phenomena so what? Everyday phenomena are dull anyway. When can we fly to Proxima Centauri, a mere distance of 4 light-years away? Science is not ended by understanding everyday phenomena. Science is about doing the incredible things that go far beyond everyday experience.

  11. Ricardo Massaro says:

    @Pieter Kok

    But doesn’t that imply that our current understanding of physics can’t completely understand classical computers either? Consider this: it’s possible to build a (classical) circuit implementing a 3SAT problem such that we can’t answer in polynomial time whether the circuit will ever output “1”.

    It seems that your requirement for “complete understanding” is unattainable a priori — regardless of the complexity of the universe.

  12. Paddy says:

    Paul Dirac said much the same thing in 1929 (but more carefully phrased, natch):

    The fundamental laws necessary for the mathematical treatment of a large part of physics and the whole of chemistry are thus completely known, and the difficulty lies only in the fact that application of these laws leads to equations that are too complex to be solved.

    But I still think Sean is being naive at a number of levels.

    For a start, scientists have been pretty smug about their explanations of everyday life for centuries, if not millenia (Epicurus would have told you a nice story about tables being made of atoms, back in 300 BC). And in many cases, especially since about 1700, they would not have been wrong; it’s just that their explanation would have had fewer “layers” than Sean’s stories. Chemists didn’t go around 100 years ago worrying that they didn’t understand the chemical bond; they took it as a given and celebrated the fact that they could use it to understand the properties of molecules. By 1929 Dirac could celebrate that chemistry had been “explained”, but his explanation would have been less “fundamental” than Sean’s: he was thinking of standard non-relativistic QM. If you’d asked Lord Kelvin in 1890 he could have explained why a table is solid in terms of chemical bonds, elasticity etc. Unlike Dirac’s unsolvable equations and Sean’s just-so stories, Kelvin’s explanation would have included some physical laws you could actually use to design a table that didn’t collapse under its own weight. So actually, the laws Sean is celebrating are neither applicable to everyday situations, nor truely fundamental. (Which is not to say that they can’t be used to help design some marvellous gadgets).

    Secondly, I’m a bit sceptical that we are stuck with electrons for ever and no paradigm shift will change that. Arguably the concept of “electrons” is already long out of date, at least insofar as it implies that electrons are unproblematic distinct objects.

    Finally, there are the emergent laws like the second law of thermodynamics and evolution by natural selection. It is not that we don’t understand where these laws come from: in both those cases the explanation is very clear. But the point is, it has nothing to do with the “fundamental” laws of electrons et al. Entropy would increase in almost any universe, even if we radically changed the fundamental laws, e.g. by replacing field theory with cellular automata. Organisms will evolve under selective pressure any time you have almost-but-not-perfect inheritance, irrespective of how you implement that. Arguably, that makes these laws much more fundamental than QFT or whatever TOE is eventually discovered. And there are very likely other emergent laws which are directly relevant to everyday life that we havn’t figured out yet. Turbulence may well be a case in point.

  13. Frank says:

    This blog http://www.science20.com/hammock_physicist/why_physicists_are_smug mentions the arrow of time as counterexample to Sean’s wefigureditallout claim.

    Any comments?

  14. Pieter Kok says:

    Ricardo,

    In both counterexamples you start with the algorithm. But I am trying to say that the nature of an explanation goes the other way: you start with the phenomena (i.e., the output of the quantum computer) and the basic laws of quantum mechanics (i.e., a universal set of quantum gates). To find an explanation of the phenomena in terms of the basic laws means you have to uncover the algorithm. You will have to use experimentation, in the form of comparing input states with output states. You may be lucky/inspired in a particular case and hit upon an algorithm that seems to work, but there is no “meta-algorithm” that will uncover the algorithm you are looking for efficiently. I would say that in this sense the phenomena are not completely understood.

    The other way around is a different case: in order to find a factoring algorithm you already have a complete specification of what the algorithm should accomplish. Remarkably, this allows you to actually prove that a given algorithm (Shor’s) does what you want it to do.

    This is slightly different from my original comment (#12), so thanks for bringing up these arguments. Even if this is not the last word in the matter (this is the Internet, after all), I strongly believe that we should treat “explanations” in a computational sense, with all the machinery of computational complexity theory that comes with it. I think this will eventually also bring about a shift in the underlying assumption that the fundamental laws are always microscopic.

  15. Nullius in Verba says:

    #24,

    What if you have two new forces that exactly cancel one another out, and screen only one of them?

    Say you gave all matter a slight net positive charge that exactly counterbalanced gravity, as well as an electric dipole moment? The electrostatic repulsion would cancel the gravity, and you would see no force between particles. But in large clouds of matter, the dipole moment would shield the electrostatic repulsion, while leaving the gravity alone.

    Or did I misunderstand?

  16. Sean Peters says:

    I’m a latecomer to the laws of physics debate here, but having read it all now from the beginning – come on, Sean. You make a very strong claim – we already know everything – and then qualify it to death with “in our everyday experience”, and “not in the details of how it all plays out”, etc. So you’ve made a claim that appears to say a lot more than it actually does, and then are all surprised that people get confused? You’re blaming readers because they didn’t pay enough attention to the fine print?

    Sure, people should have read this more carefully. And if they had, the reaction would most likely have been a big yawn, as you are not really claiming much of anything once all the qualifications have been incorporated. As an illustration, it’s just as true that the everyday experience of people in 1776 was pretty much completely explained by Newton – sure, there were some more accurate measurements to be taken of moving bodies that might have changed things, and there were some hints that all was not well in the world of thermodynamics, and there was that troubling electricity to be explained, but guess what – that’s far outside the everyday world of 1776.

    And the state of science in 200 BC pretty much completely described the everyday world then, too. Of course, objects in motion tend to slow down and come to rest – that’s plainly observable. And obviously, the earth is the center of the universe and other bodies orbit it. Sure, detailed measurements of inertia still had to be done, and there were those difficult epicycles to work out in the orbits of planets and moons, but guess what – that’s far beyond the everyday world of 200 BC.

    In reality, it seems that you wanted to make a very sweeping claim but couldn’t support it, so you watered it down with qualifications until it was meaningless. And then blamed readers for not picking up on the qualifications. Usually I really like your writing, but this whole line of argument is unbelievably weak.

  17. David Derbes says:

    Sean is surely correct about this, but a little voice tells me that the universe may have secrets we haven’t figured out about some ordinary, everyday things that, a hundred years from now, people will be surprised we didn’t know. Are we going to have a deeper understanding of Coulomb’s Law? I doubt it. Will there be a qualitatively different understanding of what protons are, or what electrons are, or of the nature of light? Unlikely.

    Still, there isn’t, as far as I know, a really good understanding of friction. Can the coefficient of friction between, say, smooth pure copper and smooth pure carbon, be calculated?

    Admittedly it was more than a long and fruitful century ago, but Kelvin thought we had *all* of physics understood at the turn of the last century, apart from the small clouds of black body radiation and the nature of the luminiferous aether. And we know how that turned out. Sean is saying that there aren’t any more clouds with respect to *everyday* physics. In my opinion only a fool would bet against him.

  18. John says:

    @Sean Peters

    It’s not just that the abundance of fine print in Sean’s argument that confuses people.

    When Sean uses the words “for the first time in history” he simply misrepresents the history of science. With all the fine print in effect, Sean could have made the same we-figured-it-all-out statement in the middle ages (as you correctly point out).

  19. Avon says:

    Sean’s attitude is the real holdup on real science – we have to wait for all of the old scientist fossils to die off. After they’ve spent their entire professional life barking up the wrong tree, do you expect them to change their minds gracefully?

    Evolution is stumbling badly, and we’re left with creationism as the only alternative?

    What about the standard model of the universe? Standard model expansion is speeding up and slowing down like a car stuck in stop-and-go traffic. The vast majority of the universe is made up of dark, negative energy (which no-one has ever seen) and dark matter (which no-one has ever seen). Those of us with less-than-advanced degrees see a forest, not trees.

    Does any-one out there have any idea why gravity works? Or why quantum mechanics works? What about light or electricity or time? We have NO IDEA why the most elementary concepts in physics do what they do. Currently all we have is empirical knowledge of the universe around us, the engineers are doing all of the work while the theorists sit around and espouse nonsense, while telling us they have all the answers.

    Real science is done by ordinary people who reject the dogma of the “standard model” and objectively study the data, realize the connection, and tell somebody. Win the vaunted Nobel prize? More likely they will be professionally burnt at the stake.

  20. Russ Abbott says:

    It maybe that the today’s physics provides a model of a platform upon which explanations of everyday experience can be built. But it seems to me that two clarifications are needed.

    1. We don’t understand completely how that platform works. For example the platform includes gravity as one of its primitive elements. Are you really satisfied simply to say that we understand the everyday phenomenon of gravity because gravitational phenomena fit the model we have built for it? There are many phenomena for which we can build descriptive models even though we don’t understand how they work.

    2. Think of some computer program whose inner workings you don’t understand. That computer program produces some phenomena. Although it’s true that the computer program executes on a computer whose elementary operations we do understand, is it really useful to say that just because we understand the underlying machine we understand how the phenomena themselves come about? It may be the case that our current model of fundamental physics is sufficiently powerful that mechanisms using that physics can bring about the sorts of complex phenomena people (including you) have cited, etc. If that’s what you want to say, then ok. But that dismisses an awful lot that we don’t understand. Point 1 then goes on to say that we don’t even fully understand how that model works.

    Perhaps it might be better to say that modern physics provides a description of a level of complexity that (a) is unlikely to change much and (b) is sufficient to serve as a platform for implementing most of what we see in our everyday lives. But (a) we don’t fully understand how that platform itself works, and (b) we don’t fully understand the workings of many of the phenomena that are built upon that platform.

  21. Jiav says:

    @Sean

    Very interesting series of post. Please count me in 3. You’re too presumptuous. New physics might be required to understand consciousness.

    While I’m deeply believing that’s not true, I will consider presomptuous to take for granted that no new physics is requiered to understand consciousness. Or, to clarify, to understand my own inner world.

    “We can’t be sure that the motion of the planets isn’t governed by hard-working angels keeping them on their orbits, in the metaphysical-certitude sense of being “sure.” That’s not a criterion that is useful in science. ”

    I don’t want to be rude in anyway, but the truth is that I think you miss the point here. It’s not about a metaphysical-certitude sense of being sure, it’s about the fact that known physic seems to be able to explain behavior with no need for consciouness or inner life. Sure, one possibility is that certain configuration of information will be proven to equate inner life. But another possibility is that behavior need no inner life to be explained by known physics. Conversely, that means that known physic might have nothing to say on what is the inner life we all experienced.

    “What would be a refutation of my claim that we understand the laws underlying everyday phenomena? Easy: point to just one example of an everyday phenomenon that provides evidence of “new physics” beyond the laws we know.”

    So I count inner life as everyday phenomena for which known physics says nothing yet, and for which we should not be too fast to rejecte the need for new physics.

    Not that I believe it, but we should be more cautious than Maxwell was.

    Best,

  22. Boaz says:

    @Avon, 44-
    This seems a bit harsh to say that Sean’s attitude is holding up science… and really disrespectful to scientists to call the old folks fossils…
    Why would you say that real science is done by those who reject the standard model? The standard model has a lot of success. People who accept the standard model are clearly also making much progress and teaching us much about the world.
    I think Sean goes wrong in wanting physics to cover more territory than it really does. He does give the qualification that “the physics” of every day life is explained. So its not that everything is explained, only physics. This is a bit of a tricky loophole, though, if you haven’t said a bit more clearly what physics is- in new contexts, 1000 years from now.
    What is physics? And how unified of a discipline is it really? What are its limitations, as currently defined? These are the grey areas I’d be interested in Sean going into a bit more depth on. (Sorry, perhaps I should read his book first, before criticizing!) Or maybe just finding a slightly different way of discussing it, so that other disciplines are given respect and seen how they fit into physics.

  23. JimV says:

    Yes, friction (nanotribology) is understood, based on the Standard Model, with the usual problem of solving very large systems of simultaneous PDE’s on the macro level.

    I’m firmly with those who see consciousness as a non-problem. In my case (can’t speak for the rest of you), billions of neurons are churning through lots of possibilities before I write each word of this sentence. I have no nerves which monitor their actions, so the results seem to arrive out of nowhere, but someday a giant super-computer with as many registers as I have neurons will be able to think as well or poorly as I do.

    In mechanical engineering we have an problem with certain welds known as “hydrogen cracking”. It turned out that quantum mechanics predicts a particular shape of hydogen bonds which explains this problem. (It took several weeks of computer work to do the calculations.)

    There are still a lot of calculations and worthwhile research to be done, but I agree with Sean – a thousand years form now there will still be hydrogen cracking if weld electrodes aren’t kept dry, and it will still be explained by quantum mechanics acccording to the Standard Model. We may or may not have the giant computers then, depending on whether our civilization keeps progressing or not.

    Yes (according to my humble opinion), there will be things we can never figure out because we aren’t smart enough, just as chimpanzees will never figure out the Standard Model.

    There is sort of a catch-22 here. Since there is no magic, just emergent behavior out of complex physical laws, it follows that emergent creatures like ourselves have lots of limitations which we would rather not acknowledge.

  24. Brian Fies says:

    Sean, I’m with you 99% of the way. But on my bookshelf I’ve got this set of Encyclopedia Britannicas from 1892 whose “Astronomy” article has pages and pages on solar spectroscopy and not one sentence attempting to explain what causes spectral lines or, indeed, how the sun shines at all. Understandable–they didn’t know fusion, they hadn’t even figured out the electron yet!–but it’s striking that there’s not a hint that such questions were significant or even worth asking. Similarly, I had an upper division astrophysics course (in the early ’80s) in which the topic of galactic missing mass came up and the prof shrugged it off as a trivial rounding error for the math guys to clean up rather than a hint that most of the universe was missing. So I always wonder: what fundamental thing sitting right in front of us are we overlooking today? What questions are we not even thinking to ask? Could a new physics of dark matter/energy or something we don’t even know we don’t know change our understanding of *everything*? It seems plausible, especially on the order of centuries. I think it unlikely, but protons, neutrons and electrons could turn out to be shadows on the cave wall that simply aren’t needed to explain reality four or five centuries from now.

  25. Sorbit says:

    The examples (table, sun etc.) are quite trivial as mentioned above. Your original claim was much stronger and now you seem to have considerably qualified it. You did good by doing this.