The Laws Underlying The Physics of Everyday Life Are Completely Understood

Not sure why people don’t make a bigger deal out of this fact. Physicists (and scientists more generally) are infamous for making grandiose claims about how close we are to Figuring It All Out, only to be shocked by some sort of revolutionary discoveries soon thereafter. Personally I have no idea how close we are to a comprehensive theory of absolutely everything. But I do know how close we are to having a comprehensive theory of the basic laws underlying the phenomena we encounter in our everyday lives — without benefit of fancy telescopes or particle accelerators or what have you. Namely, we already have it! That seems to be worth celebrating, or at least remarking upon, but you don’t hear it mentioned very much.

Obviously there are plenty of things we don’t understand. We don’t know how to quantize gravity, or what the dark matter is, or what breaks electroweak symmetry. But we don’t need to know any of those things to account for the world that is immediately apparent to us. 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. But these are manifestations of the underlying laws, not signs that our understanding of the laws are incomplete. Nobody thinks we’re going to have to invent new elementary particles or forces in order to understand high-Tc superconductivity, much less predicting the weather.

All we need to account for everything we see in our everyday lives are a handful of particles — electrons, protons, and neutrons — interacting via a few forces — the nuclear forces, gravity, and electromagnetism — subject to the basic rules of quantum mechanics and general relativity. You can substitute up and down quarks for protons and neutrons if you like, but most of us don’t notice the substructure of nucleons on a daily basis. That’s a remarkably short list of ingredients, to account for all the marvelous diversity of things we see in the world.

A hundred years ago it would have been easy to ask a basic question to which physics couldn’t provide a satisfying answer. “What keeps this table from collapsing?” “Why are there different elements?” “What kind of signal travels from the brain to your muscles?” But now we understand all that stuff. (Again, not the detailed way in which everything plays out, but the underlying principles.) Fifty years ago we more or less had it figured out, depending on how picky you want to be about the nuclear forces. But there’s no question that the human goal of figuring out the basic rules by which the easily observable world works was one that was achieved once and for all in the twentieth century.

You might question the “once and for all” part of that formulation, but it’s solid. Of course revolutions can always happen, but there’s every reason to believe that our current understanding is complete within the everyday realm. Using the framework of quantum field theory — which we have no reason to doubt in this regime — we can classify the kinds of new particles and forces that could conceivably exist, and go look for them. It’s absolutely possible that such particles and forces do exist, but they must be hidden from us somehow: either the particles are too massive to be produced, or decay too quickly to be detected, or interact too weakly to influence ordinary matter; and the forces are either too weak or too short-range to be noticed. In any of those cases, if they can’t be found by our current techniques, they are also unable to influence what we see in our everyday lives. We have very little idea how big the region of our understanding is, compared to all that there is to be understood; but we know that it’s bigger than what we need to understand to make sense of the world we see with our unaided senses.

That’s pretty amazing. Science will certainly push forward along the frontier of phenomena that are too big or small or subtle to be detected without delicate instruments, as well as along the much more jagged and unpredictable frontier of how the basic laws play out in complicated ways. But getting the basic laws right is an extremely impressive accomplishment, especially for good old human beings who have only been doing science systematically for a few centuries. Way to go, human beings!

(See follow-up posts here and here.)

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70 Responses to The Laws Underlying The Physics of Everyday Life Are Completely Understood

  1. Pingback: Tweets that mention The Laws Underlying The Physics of Everyday Life Are Completely Understood | Cosmic Variance | Discover Magazine -- Topsy.com

  2. nick herbert says:

    Source: UCSC physics professor Bruce Rosenblum:
    “Classical physics could explain the world
    but got some of the details wrong;
    Quantum physics gets all the details right
    but can’t explain the world.”

  3. @Amos Zeeberg, you have said it all [rejection of John Horgan’s End of Science thesis].Also’ @ Anthony McCarthy, your proposition is educative and i like your argument.

  4. Alan says:

    Nice one, Dr. Herbert!

  5. Kay says:

    Unless you even have the slightest idea on what is happening on all the dimensions and how it effects the dimension we live on then you all are just guessing as much as anyone lay person or whatever and all the credentials and astro-minds of the universe don’t really have a clue what’s going on or if they do they are not telling.

  6. Cosmonut says:

    Sean, you say that:

    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…. But these are manifestations of the underlying laws, not signs that our understanding of the laws are incomplete.
    —————

    My question is, how would we know that consciousness or even high temperature superconductivity ARE really just manifestations of the underlying laws we know, unless we have already succeeded in explaining them in terms of those laws ?

    In other words, as long as the “jagged frontier” remains, we can’t really say that the the laws of physics we know will definitely explain everything on the everyday scale, can we ?

  7. Gammaburst says:

    The heart has it’s reasons which reason knows nothing of. (Blaise Pascal)

  8. Doug says:

    “In other words, as long as the “jagged frontier” remains, we can’t really say that the the laws of physics we know will definitely explain everything on the everyday scale, can we ?”

    Well, we know consciousness is a product of brains, and brains operate according to physics, so yes, we can assert with confidence, though perhaps not definitively, that it can be explained with physics we already know the fundamentals of. There is no magic consciousness substance in the brain, there is simply patterns of neuron activity. This isn’t even the quantum regime, we’re talking about classical physics.

  9. Nullius in Verba says:

    Is the second law of thermodynamics a manifestation of the known microscopic laws? How about the irreversibility of wavefunction collapse, if such a thing happens? Time and certainty seem pretty fundamental to the everyday.

    “There is nothing new to be discovered in physics now, All that remains is more and more precise measurement.”
    Lord Kelvin, 1900.

  10. j says:

    Interesting idea. My interpretation of things is not the same as yours.
    I find you core assertion not true. For instance; we do not understand inertia or even magnetism on a truly fundamental level. Yes we can model stuff and have immense engineering abilities… but ‘the physics of everyday life completely understood?’ . i for one disagree… mysteries are all around.

  11. Cosmonut says:

    @58- Doug:
    I guess what you said is what Sean is arguing for as well.

    But my point is that the statement – “Consciousness is a product of brains and brains are classical physics systems” is a *hypothesis*.
    It might be a true hypothesis, but you can’t say for certain until you actually test and prove it – explain consciousness in terms of cell behaviour and cells in terms of physics.
    (Nothing special about consciousness, it could be superconductivity or weather.)

    The best one can do is argue on lines like “since our physics has explained so much about the everyday world, we strongly believe that all other phenomena on the everyday world will also turn out to be a consequence of known physics.”

    I guess all it means is that Sean should add a parenthetic ‘very probably’ to the heading. :)

  12. Dionigi says:

    I think we have an explanation for the way things work as we see them this does not mean our explanation is true even if it is testable and repeatable. Ptolomy had a good explanation for the movement of planets but is was not elegant. Quantum theory explains what we see at micro levels but is by no means elegant or satisfying. One day another Newton / Einstein will come along and every one will smack their foreheads. As for whether what we see is reality or not it doesn’t matter we are stuck with it and have no choice between the blue or red pill.

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  14. bittergradstudent says:

    @Nullius:

    Wavefunction collapse isn’t irreversible at all. Quantum decoherence is a huge, huge problem for people trying to take advantage of wavefunction collapse, actually.

  15. Pingback: Seriously, The Laws Underlying The Physics of Everyday Life Really Are Completely Understood | Cosmic Variance | Discover Magazine

  16. Edward says:

    We don’t have a good understanding of nonlinear systems, which are ubiquitous in nature.

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  18. jofr says:

    Yes, it is true, you can only discover a new world once, whether it is America or the Science of everyday day life. Feynman knew this. He said “we are very lucky to live in an age in which we are still making discoveries. It is like the discovery of America – you only discover it once.” We have reached the limits of the very large and the very small, but there is still the world of the very complex, where things are confusing and complicated. And there is the world of programs which form the computational universe and all kinds of virtual worlds (what Stephen Wolfram likes to call a new kind of science). And maybe something completely different. They told Max Planck in 1878 that almost everything is already discovered, and all that remains is to fill a few unimportant holes. You know what happened then. We do not know all kinds of possible worlds yet, and this is just the beginning, because things get interesting when worlds interact with each other, if universes meet and worlds collide.

  19. Swampfox48 says:

    So what! To what end? Oh yea, I get to watch a football game in 3D. Hal-lay-louya

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