Seriously, The Laws Underlying The Physics of Everyday Life Really Are Completely Understood

While the primary purpose of last week’s post on the laws of physics underlying everyday life was to convey information like a good blog post should, there was another agenda as well: to test the waters. This is an issue I’ve been thinking about a lot lately, but I wanted to get a better idea for how it’s perceived in the outside world. I honestly wasn’t sure whether there would be more of “you arrogant physicist, we don’t have any idea what the laws are” or “you moron, why are you wasting our time with this self-evident crap?”

So much for that ambiguity. Responses, for example at Fark and Reddit but even here in our very own comment section, displayed a greater than average internetitude, defined as a tendency to not read the article, set up straw men, and miss the point. But at least the direction of disagreement was fairly uniform. The issue under discussion is important, so it’s worth taking the time to counter the three most common arguments, from completely silly to almost-sensible.

1. Are you serious? There’s so much we don’t understand: turbulence, consciousness, the gravitational N-body problem, photosynthesis…

To which my years of academic training have prepared me to reply: duh. To conclude from my post that I was convinced we had a full understanding of any of those things represents, at a minimum, a rather uncharitable reading, given that no one in their right mind thinks we have such an understanding. Nevertheless, I knew people would raise this point as if it were an objection, which is why I was extra careful to say “We certainly don’t have anything close to a complete understanding of how the basic laws actually play out in the real world — we don’t understand high-temperature superconductivity, or for that matter human consciousness, or a cure for cancer, or predicting the weather, or how best to regulate our financial system.” And then, at a risk of being repetitive and boring, I added “Again, not the detailed way in which everything plays out, but the underlying principles.” And for emphasis there was something about “the much more jagged and unpredictable frontier of how the basic laws play out in complicated ways.” Nevertheless.

The distinction I’m drawing is between the laws underlying various phenomena, and how the phenomena actually behave, especially on macroscopic scales. Newtonian gravity provides an excellent example of the difference: we certainly know the laws underlying the behavior of gravitating particles in the Newtonian regime, but that obviously does not mean we have a complete solution to the N-body problem, or even a qualitative understanding of how large collections of particles behave. It’s the difference between knowing the rules by which chess is played, and being a grandmaster. Those are not the same thing. In particular, taunting “you’re no grandmaster!” is not actually a refutation of the claim that I know the rules of chess. My claim was that we know the basic equations governing the behavior of matter and energy in the everyday regime — not that we have a complete understanding of every observable phenomenon.

It is of course completely legitimate not to care that we know the basic underlying laws. You may not think that’s interesting, or very important. That’s fine, I certainly wasn’t making any claims at all about priority or importance or interestingness. But it should still be possible to understand the claim I was making, and judge it on its own merits, such as they are.

Let me just emphasize how non-trivial the claim is. First, that there is such a thing as an “underlying” set of laws. That is, that we can think of everyday objects as being composed of individual pieces, such that those pieces obey laws that are the same independently of the larger context. (Electrons obey the same equations of motion whether they are in a rock or in a human heart.) That’s the reductionist step. Again, for people who enjoy taking offense: this is not to say that the reductionist description is the only interesting one, or to imply that the right way to attack macroscopic problems is to reduce them to microscopic ones; only that the microscopic laws exist, and work, and are complete within their realms of validity. And second, that we know what those laws are. There’s nothing in the everyday world that is inconsistent with Standard Model particles obeying the rules of quantum field theory, plus general relativity to describe gravity. Amazing.

2. We don’t even understand gravity! And the Second Law of Thermodynamics! And quantum mechanics! (Magnets! How do they work???)

Unlike the previous objection, this one is not correct-but-misplaced, it’s just wrong. But it’s wrong in an interesting way. We actually do understand gravity: it is described by Einstein’s general relativity. Not deep down at the quantum level, of course, but that’s very far from the world of the “everyday.” You might try to make some profound epistemological claim that we don’t really understand gravity, we just have a set of rules that it unambiguously obeys. Fine; I would argue that this isn’t an especially helpful distinction in this case, but in any event it’s beside the point. What I meant was that we have a clear set of rules that are unambiguously obeyed. That’s also true for the Second Law — it was explained by Boltzmann. Sure, we have to invoke a low-entropy boundary condition at the Big Bang, but guess what? The Big Bang is not within the realm of our everyday experience. Even the collapse of the wave function, which comes closest to a true mystery, doesn’t qualify. For one thing, wave function collapse isn’t something you see happening in your kitchen on an everyday basis. But more importantly, we do have a theory that describes what happens, handed down to us by Bohr and Heisenberg. You might think that this theory is unsatisfying and incomplete, and I would be extremely sympathetic. But it fits all the data we have. I’m not trying to make a deep philosophical point about the meaning of “understanding”; just noting that things obey laws, and in the everyday regime we know what those laws are.

3. You’re too presumptuous. New physics might be required to understand consciousness, or wave function collapse, or…

This comes closest to an actual argument, and I wish that the entire conversation could have focused on relatively sensible points of this form. But ultimately, I don’t buy it, not even close. Take consciousness as an example. Obviously there are a lot of things about the workings of the human mind that we don’t understand. So how can we be so sure that new physics isn’t involved?

Of course we can’t be sure, but that’s not the point. 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. Rather, in the face of admittedly incomplete understanding, we evaluate the relative merits of competing hypotheses. In this case, one hypothesis says that the operation of the brain is affected in a rather ill-defined way by influences that are not described by the known laws of physics, and that these effects will ultimately help us make sense of human consciousness; the other says that brains are complicated, so it’s no surprise that we don’t understand everything, but that an ultimate explanation will fit comfortably within the framework of known fundamental physics. This is not really a close call; by conventional scientific measures, the idea that known physics will be able to account for the brain is enormously far in the lead. To persuade anyone otherwise, you would have to point to something the brain does that is in apparent conflict with the Standard Model or general relativity. (Bending spoons across large distances would qualify.) Until then, the fact that something is complicated isn’t evidence that the particular collection of atoms we call the brain obeys different rules than other collections of atoms.

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. Something directly visible that requires a violation of general relativity or the Standard Model. That’s all it would take, but there aren’t any such phenomena.

A century ago, that would have been incredibly easy to do; the world of Newtonian mechanics plus Maxwell’s equations wasn’t able to account for why the Sun shines, or why tables are solid. Now we do understand how to account for those things in terms of known laws of physics. I am not, as a hopelessly optimistic scientist from the year 1900 might have been tempted to do, predicting that soon we will understand everything. That’s an invitation to ridicule. Indeed, we know lots of cases where the known laws of physics are manifestly insufficient: dark matter, dark energy, electroweak symmetry breaking, the Big Bang, quantum gravity, the matter/antimatter asymmetry, and so on. We might answer all these questions soon, or it might take a really long time. But these are all rather dramatically outside our everyday experience. When it comes to everyday phenomena that are incompletely understood, from consciousness to photosynthesis, there is every reason to believe that an ultimate explanation will be obtained within the framework of the underlying laws we know, not from stepping outside that framework. An impressive accomplishment.

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125 Responses to Seriously, The Laws Underlying The Physics of Everyday Life Really Are Completely Understood

  1. Scott_Bot says:

    “A century ago it was very easy to point to features of everyday life that were in blatant contradiction to physics as it was then understood. Today, it is impossible to do that. A century ago, people were foolishly guessing that we were close to knowing all of the underlying laws. I am very explicitly not saying that.”

    Until about 1880-1885, people assumed the supposed “contradictions” were either fringe (and thus did not matter for everyday life) or they would submit that they were not underlying contradictions, merely puzzle pieces not yet filled in. We have the luxury in retrospect to see their system was flawed, but they would have suggested it was simply incomplete. You’re not suggesting that we know all the underlying laws, but you are implying that the underlying laws we have for basic things (say, Relativity) are correct ones.

    “You may think I am smug if you like, but if you don’t see the difference between what I’m saying now and what people were saying in 1900, you are making a mistake.
    Again, it would be really easy to refute what I’m saying: point to something in everyday life that can’t be accommodated by the Standard Model plus general relativity.”

    I’m suggesting you’re smug, but I’m also suggesting that’s not a bad thing. You misread me if you think that I’m saying you’re wrong. Our model does explain everything in our every day life as it currently exists and under our current framework of what constitutes “basic” and “everyday.” That is to say, you are correct, much like they were correct at the turn of the century; what’s changed is that we have updated conceptions of basic and everyday.

    Of course we know way more now than we knew then, so we can also see that certain aspects are fundamental and important that they would not have worried or thought about. And while I think your smugness is the same, I realize your claims are different, and I don’t find fault in either yours or theirs at the turn of the century.

    “If you honestly believe that we have evidence that electrons behave differently when they are part of brains than when they are part of rocks, by all means make that argument. Vague declarations that ‘we don’t know everything’ and ‘we shouldn’t be so smug’ don’t cut the mustard.”

    I don’t honestly believe that, nor would I make that argument. I do believe that, given that every scientific system ever created except our current ones are wrong, so too will ours be. Of course, subsequent systems have been a great deal *less wrong*. Obviously I have no substantive reasoning behind this belief besides historical induction, but given that I have no evidence that our current scientific model is any more solid than the one before it was compared to its predecessor, I see no reason to extend absolute certainty to this one.

    By all means though, as scientists we should keep assuming our system is the correct one until evidence shows otherwise. Just because we don’t have that evidence yet, though, doesn’t mean we should be blind to its possibility (and, via that historical induction, its probability).

  2. Scott_Bot says:

    A little addendum: I think you’re right, but I think in another 100 years there will be similar claims made, both about their contemporary science and their past (us.) We can both be right, as long as conceptions of basic, everyday, underlying, etc. change sufficiently.

  3. bittergradstudent says:

    @MT-LA #13: Yes, we understand with very good detail how time behaves in gravitational fields. Any calculations you want to make can be made unambiguously.

    @Sean #18: There are certainly things we don’t completely understand about quantum coherence and wavefunction collapse. There are multiple existing models with differing predictions that match all existing data on these points. Its not inconceivable (not proven, but not inconceivable) that this could have a low energy consequence that is important for everyday life. Much as you would not have expected solid state physics to be determined by quantum mechanics and Maxwell theory in the 19th century.

  4. Mike says:

    “And they were right”

    “well, some of them were right, some of them were
    wildly wrong.”

    No, anyone who thought that our best theories we’re closer than ever before, was right. Did they have “wrong” aspects — of course. Were they complete — no? Have they been supplanted with greater and richer detail, and in some cases changed and revised substantially — yes. But, were our best theories then closer than ever before — without a doubt.

  5. jpd says:

    someone in the 1600’s thought angels danced on pin heads,
    were they closer to reality than aristotle ?

  6. Mike says:

    “someone in the 1600’s thought angels danced on pin heads,
    were they closer to reality than aristotle ?”

    There are idiots today who think than angels danced on pin heads. What does that have to do with it? Our best theories today are better and closer to reality than in the 1600’s or in the time of Aristotle.

    You don’t really believe that to be untrue — do you?

  7. Jens says:

    Of topic, but I thought today’s xkcd was very close to a post you had earlier, Sean, regarding Stephen Hawking. Enjoy:

  8. spyder says:

    In reading through the comment thread, i was pleasantly surprised to find that many of the things i was thinking after reading Sean’s post, were mentioned. I do think that the construct “a century ago” is itself rather wishy washy. Given that a century ago was 1910, the advances in science were well underway, leading quickly in some respects to the experiments that 30 years later led to the nuclearization of the planet (that is pretty powerful stuff). We have laws concerning the growth of scientific knowledge, computing power, technological advance and so forth; these are understood and thus are part of our everyday knowledge. We have vast imaginative capabilities; but in many ways we are closer to Kurzweil singularity, where humans will no longer have the capability to imagine more of the future, than to Jules Verne and Issac Asimov.

    The analogy that works best for me is the thought that we have moved forward, quite rapidly, along the spectrum of garnering knowledge of the laws of nature and how they operate on everyday life. We are now in the shrinking fractional endgame so to speak. The problem is that fractions shrink to infinity, thus making it ever more near impossible to get to the complete epistemological structure. No great leaps, but millions of incrementally tiny steps must be taken. Brain research already shows us that infant humans conceptualize, and quickly learn to textualize, the world around them. The tiny steps are getting smaller and smaller.

  9. max says:

    I will repeat my objection from the last post. It is largely semantic, but I think important. You say that “the microscopic laws exist, and work, and are complete within their realms of validity. And second, that we know what those laws are. There’s nothing in the everyday world that is inconsistent with Standard Model particles obeying the rules of quantum field theory, plus general relativity to describe gravity.” I completely agree with this statement, barring the problem of consciousness (you need to be much more careful here, as others have noted). However, it seems a slight abuse of language to claim that this implies that we understand all of the macroscopic laws. If we truly understood the laws, then we would know why those laws exist, and why nature picked out our set of physical laws instead of some other laws. If you simply changed the word “understood” to “known” I would find your statement much more palatable.

    Also, the hard problem of consciousness is hard enough that you should definitely leave it out of this analysis. I know that many people will agree with you when you say that consciousness can be fully described by currently understood fundamental interactions, but many others won’t (see for example David Chalmers). Since there is a strong disagreement in this area, and since you presumably don’t have expertise here, you shouldn’t state with such certainty that your view is right.

  10. jpd says:

    i am just saying the pinhead people thought that was the best theory of reality.
    i am not sure if i am a pinhead.

    (see also leeches, alchemy, etc)

  11. Tony Arcieri says:

    I see lots of responses in the vein of: “New physics might be required to understand consciousness”

    That argument can be made about any problem. Consciousness isn’t special. What matters is evidence. There is no evidence than anything more than classical mechanics is involved in brain function. Beyond that, there is no reason to believe that consciousness is anything more than the result of brain function.

    The closest any have come to creating a scientific basis for non-classical brain function is the second round of Penrose/Hameroff Orch-Or, after their original proposals regarding the effect of quantum decoherence were refuted by Max Tegmark. The next round of Orch-Or merely hypothesizes a mechanism whereby quantum mechanics could maybe possibly impact brain function in a non-classical manner, and their proposal cannot be immediately be refuted. However, that’s no different from saying God is there, he just exists outside our light cone. Sure, we can’t outright say that Penrose/Hameroff are *WRONG*, but there is absolutely zero evidence of their position whatsoever, so there’s absolutely no reason to think they’re right.

    Materialism is the only scientific way to approach the problem of consciousness, and the computational theory of mind best fits the available evidence. Other proposals, particularly ones involving quantum mechanical doorways to magical metaphysical consciousness land, are completely without evidence and there’s absolutely no reason for a scientific thinker to support them over classical models. On rare occasions biology has managed to tap into distinctly quantum mechanical behavior, but in the case of consciousness there’s absolutely no reason and no evidence which would lead us to conclude that “new physics” or even quantum mechanics are required to understand the problem.

  12. jpd says:

    actually alchemy is a better example.
    Newton was an alchemist, he obviously thought it was the
    best theory of nature, but it was wildly wrong.

  13. Scott_Bot says:

    @jpd “it was alchemy that provided corpuscular theorists with the experimental means to debunk scholastic theories of perfect mixture and to demonstrate the retrievability of material ingredients.” (Newman, 2006)

    Alchemy was actually pretty important for chemistry and corpuscular (particle) physics, so your claims don’t hold. Also, just because someone does good science in one field doesn’t mean they do it in all fields.

  14. Mike says:

    “Newton was an alchemist, he obviously thought it was the
    best theory of nature, but it was wildly wrong.”

    Alchemy was clearly wrong in many respects — but it was a forerunner to modern chemistry — and some of its conclusions regarding basic elements and the scientific process were great advancements — much better than chants, prayers and the like. Of course, modern chemistry is “much closer” to reality than alchemy. 🙂

    Oh, I just saw Scott-Bot #38’s comments — exactly

  15. Pingback: The Distorting Effect of Scientific Revolutions | The Finch and Pea

  16. max says:

    Tony Arcieri, could you please provide one piece of evidence that materialism is right and that it can solve the hard problem of consciousness? Has anyone come up with a reasonable theory for how fundamental physics can give rise to _subjective_ experience? If so, I would very much like to hear about it.

  17. eukaryote says:

    I think consciousness IS special, because a conventionally physical description of the brain, no matter how detailed, is going to still be a description of conventionally physical properties, in conventional physical terms, that can be expressed mathematically. The contents of conscious experience on the other hand, don’t appear to be susceptible to being modeled by those same physical terms. That’s not to say that they aren’t physical, but certainly not in any way that we currently understand.

    If we acknowledge that phenomenological experience is indeed something that merits an explanation, (which I think is unassailable), then we have to accept that there is more to nature than just what is currently described in our physical models.

    Please see Galen Strawson “Consciousness And Its Place In Nature” for a lively discussion of these issues, if not for a full-on endorsement of panpsycism.

  18. Mike says:

    “could you please provide one piece of evidence that materialism is right and that it can solve the hard problem of consciousness? Has anyone come up with a reasonable theory for how fundamental physics can give rise to _subjective_ experience? If so, I would very much like to hear about it.”

    The computer through which you posted your comment is one piece of evidence that materialism is right. 😉 Regarding consciousness, science will answer this question in time — it is after all making great progress, which is only increasing in speed. In the meantime you are free of course to posit some non-material, God, spirit, the perpetual unknown or whatever, to fill in what will inevitably turn out to be a temporary gap in our knowledge.

    “there is more to nature than just what is currently described in our physical models”

    Of course there is. Sean said this a number of times and no one disputes it. Our physical models will improve — you can count on it. Will we ever know everything there is to know — I don’t believe that’s possible. But, we will know how and why consciousness arises, and it will be physical, albeit emergent and not merely reductionist.

    “Without the *why*, all we have is the power to predict”

    Agreed, what we ultimately seek are explanations and not merely predictions. All of the best science through the ages has made progress in this regard — and that process will continue.

  19. MT-LA says:

    @bittergradstudent (#28): Thanks for the response, but its not really what I was asking. You said we understand *how* time changes, meaning you can predict it, with a high level of accuracy I might add. And I agree with you.

    But I was asking if we understand *why*.

    The analogy: I can predict that you’re going to move the king because your opponent just said “check”, but I don’t know why you’re going to do it.

    Without the *why*, all we have is the power to predict. Without *why*, I don’t think I would call it “understanding”.

    In hindsight, I suppose this is a category-2 question, which means it’s already been addressed in the eyes of the moderator.

  20. Sergiy Koshkin says:

    “What I meant was that we have a clear set of rules that are unambiguously obeyed. That’s also true for the Second Law — it was explained by Boltzmann. Sure, we have to invoke a low-entropy boundary condition at the Big Bang…”

    I am not sure what exactly was explained by Boltzmann. The Second Law remains inconsistent with the Poincare recurrence theorem among other things. Assuming that the universe can be treated as a closed Hamiltonian system, low-entropy initial state does not help. According to the Liouville equation, entropy should remain constant, not increase, for any initial state. Boltzmann’s derivation of the H-theorem is mathematically erroneous, as was pointed out by Zermelo and Poincare, and the theorem itself is false without an extra assumption, equivalent to what it attempts to prove. I don’t think you are referring to Boltzmann’s giant fluctuation hypothesis either. So far statistical mechanics has been unable to reconcile the second law with Hamiltonian dynamics, although I would agree that the problem is largely academic.

  21. jpd says:

    all i am saying is i wouldn’t be surprised if one of our
    assumptions for basic physical laws was wrong.

    its happened before.
    you can say its the forerunner to whatever is next
    if it makes you feel better.

  22. Tevong says:

    Sean all I can say is I admire your patience. Your post leaves no room for misinterpretation yet somehow…

    I think you’ll be sympathetic to Asimov’s excellent writing on “the relativity of wrong”, in which he is responding to essentially the same criticisms you’re facing:

    Some short excerpts:

    “It seemed that in one of my innumerable essays, I had expressed a certain gladness at living in a century in which we finally got the basis of the universe straight.

    I didn’t go into detail in the matter, but what I meant was that we now know the basic rules governing the universe, together with the gravitational interrelationships of its gross components, as shown in the theory of relativity worked out between 1905 and 1916. We also know the basic rules governing the subatomic particles and their interrelationships, since these are very neatly described by the quantum theory worked out between 1900 and 1930. What’s more, we have found that the galaxies and clusters of galaxies are the basic units of the physical universe, as discovered between 1920 and 1930.

    The young specialist in English Lit, having quoted me, went on to lecture me severely on the fact that in every century people have thought they understood the universe at last, and in every century they were proved to be wrong. “

  23. Alan says:


    I know you say that “bending spoons across large distances would qualify” and I certainly could relate an account observed by Professor Arthur Ellison (electrical engineering, City University) and Arthur Koestler or one observed in Professor Hasted’s lab at Birkbeck College, London University! Next post? 😉

    But (anyway) how about the famous remote perturbing of a highly shielded (electrically, magnetically, thermally, and deeply buried) magnetometer used in a quark detection experiment? (when it was thought quarks could maybe exist singly).
    This was an unannounced “test” on the artist Ingo Swann by Dr. Hal Puthoff at Stanford University in 1972. Some other physicists involved said to the effect that it would be impressive if Swann could disturb this device. Swann did this three times (the results were measured) then drew a pretty good diagram of the (unpublished) details of the device. After this the device functioned normally, nicely cycling to order.

    This is very curious. How could a human being initiate this effect and also see the apparatus? Swann, quite nontechnical in his qualifications, really saw this buried highly technical device.
    And why should he be able to see it? This is crucial.

    The full account is at:

    For a pleasant talk by Dr. Puthoff precisely on this paper (with the magnetometer perturbation data):

    This result led to the beginning of the Stanford Research Institute CIA-funded remote-viewing programme, 1972-1985 (Puthoff’s studies). Ingo Swann was one of the top RVers recruited.

    The point is that people can accurately “see” across space (and time – the experiments showed). Are there aspects of known physics that explain this or is new physics being revealed here? This is a fair question. Perhaps the disturbance of the magnetometer can be explained, but the actual visualisation of the magnetometer suggests something else is involved.
    And of course, if we all have this ability to some degree, then this qualifies as an everyday life phenomenon.

  24. Pete says:

    Can I somehow get a discover science RSS feed that excludes Sean’s posts? I’m tired of him wasting my time with this self-evident crap.

  25. James says:

    So why are things solid, then?