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. NewEnglandBob says:

    The problem is not with you or what you said, Sean.

  2. Peter Morgan says:

    But are you certain, **certain**, that there’s no phlogiston in our models? I feel sure, from experience, that we will be able to tell a Whiggish history of how we were right all along, that both Newton’s theory of gravity and Einstein’s theory of gravity are true, but it seems at least equally intellectually honest to say that Newton’s theory was false in *some* sense. We go to considerable lengths to tell kids that weight is different from mass, a distinction that is part of the separation of Newton from earlier Physics; why do we bother if it doesn’t change anything?

    This is just the pessimistic metainduction, no big deal, some people think it’s a potent argument, others don’t. If someone finds good empirical evidence for string theory, or someone else proves that there are both big bang cosmological models and non-big-bang cosmological models that are consistent with any experimental evidence that satisfies some very natural set of conditions (thereby weakening empirical support for Big Bang Cosmologies), does such a thing change the world, for us, or not?

    I would say that if we use sledgehammers, such subtleties make no difference, but we are restricted to what we can achieve with sledgehammers, whereas we can achieve much more if we pay attention to subtlety and detail. It doesn’t seem right for me not to feel an earthquake when I first understand a small part of some subtlety that scientists spent decades or centuries discovering and inventing for us.

    However —I would say like you—, this is just repeating myself.

  3. Non-Believer says:

    Heroic Sean. Its easier to give up but you won’t. And that is why eventually the human race may get educated and leave behind the idea that magical things are running the universe.

    I agree that our world is entirely explainable and what we already know will lead us to more understanding. It is not mysterious magic.

    I wonder if you think its possible that there will be a depth of understanding that the human brain is incapable of processing. I look at quantam physics today and I can hardly follow the basics. Many of the common illustrations of how it works have led me to errors in understanding. I am credited with an above average intelligence. Surely at some point there are concepts that our brains are not capable of coping with, even with extraordinary intelligence and years of study.

    Of course, there is the idea that we wouldn’t recognize our inability and would either adapt a solution or not realize those levels of reality exist.

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  5. Sarang says:

    “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.”

    I guess there are two different interpretations of “why is a table solid?” — (a) why is it solid at such-and-such a temperature, (b) why is “solid” a meaningful concept, and what defines this concept? (a) is admittedly a microscopic question, (b) has nothing to do with microscopics. If I were to ask you why the acoustic phonon spectrum of a solid is linear at low frequencies and you tried to explain that it was because the stuff consisted of molecules which consisted of atoms, I think that would be a _terrible_ explanation.

  6. Tevong says:

    For those fixated on the fact that giants in the past have been shown to be wrong so we shouldn’t be so confident of our own theories nowadays, the fact is Newton wasn’t wrong. His laws are still correct at describing things on everyday scales, just like classical electromagnetism isn’t invalidated by a deeper, more fundamental theory and we suddenly find all our generators and motors stop working the day quantum mechanics is discovered.

    I’ll repost the link to Asimov’s essay on the relativity of wrong here:

    http://chem.tufts.edu/answersinscience/relativityofwrong.htm

  7. Keith says:

    Sean … Pace NewEnglandBob we have to somehow get people to read the words that are written and not the words they think (or would like to) have been written.

    In following many of the comments on your posts I have been truly staggered — almost to the point of pulling out my remaining grey hair — that readers have totally failed to grasp that you are discussing the basic physics of our everyday world and experience of tables, cars, footballs and satellites, and not that of quantum entanglement, complex neurology, intricate photochemistry or a “grand unified theory of everything and its dog”.

  8. Cosmonut says:

    Sean, with regards to:
    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.
    ———————–
    What if you get some new force/laws which comes into play at the level of collective phenomena at the everyday level and is crucial for explaining them ? So, suppose you simulate something very complex using known physics and you find it doesn’t work out.
    With what confidence can we say that this can’t happen ?

    I agree with you that unlike a 100 years back, we can’t immediately point to an existing phenomenon – like the Sun shining – and show that it isn’t explained by known physics.
    But I guess, a hundred years back, the unexplained everyday phenomena were simpler to model, and hence, you could show more easily that your known physics failed.

    But nowadays, the unexplained frontier involves far more complex things like biological organisms, consciousness etc – so wouldn’t it be far more difficult to see if the known laws explain them adequately, or not ?

  9. John says:

    Sean: “one thousand years from now, you will still hear precisely that same story”.

    That is the point. Obviously that will be the case for the (by now) trivial examples you quote. But for the unexplored everyday territories of the arrow of time, free will, consciousness, etc. this is very doubtful. I am not claiming these phenomena are outside the realm of physics, but they likely will require new insights at a fundamental level.

    Thousand years from now, long after the discovery of holographic zylbot dynamics, people will look back at these ignorant 21st century folks: how come they didn’t realize zylbots would solve all the quantumgravitational inconsistencies in their simplistic theories and give them a theory of consciousness at the same time?

    Zylbots are not hiding from us, we are just not clever enough (yet) to recognize them.

  10. jpd says:

    i will give up after this, but
    re Tevong:
    Newton was right about a lot, but he was also wrong.
    alchemy was wrong.
    he thought it explained some things , but it was wrong.

  11. PPK says:

    Sean: “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.”

    There may easily be as dramatic a paradigm shift in the future as any we had in the past, for example we could return to determinism, space and time could prove to not be fundamental, Lorentz invariance could prove to be an approximation, but most importantly there may be something completely new, something that we cannot even imagine now, just like QM and GR brought completely new qualities to physics.

    Fundamental particles and forces that are crucial to telling the story of everyday phenomena may also be discovered, until we can predict every last property from first principles there is certainly no reason to believe we found them all. For example there could be other weak fields present which influence outcomes of events which we so far take to be random. Or particles may turn out to have a complex which affects their behavior, and again there may be things which we cannot even imagine yet.

    Of course most of the laws which describe experiments will remain as they are today, but their status will change, they will be relegated to approximations.

  12. Pieter Kok says:

    Sean,

    The original statement, The Laws Underlying The Physics of Everyday Life Are Completely Understood seems to make the silent assumption that these laws are microscopic, e.g., about quarks, photons, electrons, etc. Then there are the “emergent” laws that people bring up as counterexamples. If I understand you correctly, you argue that these are ultimately reducible to the well-known interplay between the fundamental building blocks I mentioned before.

    So far, so good. But then you use the phrase “completely understood”, which I take to mean that there exists an algorithm based on the underlying laws that can reproduce the emergent law. We then have to worry about the (technical) computational complexity of the algorithm. If the system consists of N particles, the algorithm must produce an output in poly(N) time. If the computational complexity scales exponentially the problem is intractable, and I would not consider such an algorithm a valid explanation of the emergent law. It is the same distinction between evanescent and propagating waves: in both cases the field amplitude is nonzero arbitrarily far from the source, but still we call only one solution “propagating”.

    You may object: but Nature is a computer that calculates the algorithm in poly(N) time. To which I counter: an explanation is a classical algorithm (because our mind operates in a classical way), but Nature is a quantum computer. If quantum computers are strictly more powerful than classical computers (i.e., if BQP > BPP), and if the emergent laws are in this class of problems, then I would say that your statement is false.

  13. Aaron Wright says:

    Hi Sean,
    My sympathies for the “internetitude” you’re getting. I’ve read your posts but not all the comments. I have a couple of quick observations, if people are interested in more, I’ll put something up on my blog. First, you’re right that `we don’t understand the connection between the underlying laws and the macro behaviour’ doesn’t refute your points. Nevertheless, it is an answer to what I took to be your primary point: why don’t people make a big deal of our knowledge of this stuff? It’s a similar point to the observation that people deride Philosophy or English, etc. because it’s not practical.

    But, of course, it _is_ very practical…and here’s where I think you should look for people expounding on the incredible understanding we have of `basic’ physics: patent applications. That is, engineers and technologists rely on this understanding, say in designing a new waveguide/antenna for a cell phone.

    And maybe this goes some way to explaining the reactions your piece got. What people expect from physicists, especially physicists in the news / public / internet, is crazynewincrediblethingsthatblowyourmind. Physics reporting and popular books are often sensational. When you start to praise the calmer (still beautiful to us of course) physics, it’s like coming to a boxing match to find people playing chess.

    Cheers,
    Aaron

  14. Dreamer says:

    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.

    While that may seem obvious to many, it is amazing how often people refuse to accept this simple fact — mostly by pseudoscientists and ID/creationists of course, who have a vested interest in the chance that firmly established scientific theory can still be overturned. Indeed, you will still find creationists who, somewhat astonishingly, quite seriously refuse to accept the majority of the last 100 years of physics — anything from Einstein onwards:

    http://www.commonsensescience.org/explaining_life.html

    @8:Cosmonut:

    But nowadays, the unexplained frontier involves far more complex things like biological organisms, consciousness etc – so wouldn’t it be far more difficult to see if the known laws explain them adequately, or not ?

    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? While nothing is impossible, there doesn’t appear to be any good scientific reason why complexity requires an additional, as yet undiscovered, branch of physics. And even if there is one, it’s unlikely to provide any additional explanatory power for phenomena of the same scale as biological entities, any more than Einstein added to the calculation of the trajectories of WWII artillery.

  15. Brian says:

    Zylbots is starting to sound like “physics of the gaps” …

  16. Cody says:

    “For what was true yesterday would be true still, and new knowledge could not make old knowledge false,” J. Robert Oppenheimer

    It’s strange how much difficulty people have in understanding the convergent, tentative, and approximate constraints of science.

    I also don’t understand why people find consciousness so mysterious; if you’ve ever watched a dog hold it’s breath on a hot day to listen for a noise it thinks it heard (like a knock on the door), then you know why animals evolved sophisticated systems for decision making, and anyone who knows anything about head injuries is well aware of a brain’s sensitive reliance on physical structure, so it’s not like there is a soul or phlogiston or a thetan or something.

  17. Richard L says:

    I just have to say that I agree with the Sean on this post… everyday stuff is quite easy to explain using the physics we know today – though I still seem to get some calculation error on my exams :/

    I like the message of this blog post, it’s something worth pondering on before falling asleep at night (to my experience, this is the best time to get good thinking done).

    What we can perceive with our senses, in our everyday experience, is explained by the physics we know today and nothing will change that. Be it light, warmth, sound or by tactile measures, our everyday physics is known.

    I’ll add that I disagree with all of the ‘literature students’ [see the link by other commentator to Asimov] and people stating that stuff like free will, consciousness and the mere existence of matter is everyday stuff… in what way is philosophy part of everyday experience? And as stated in an earlier blog-post (I think) – why won’t you add the financial sectors investments to that list? It’s pretty much the same as the question of free will…

  18. spyder says:

    There are a number of people who wish to impose “what if” and “maybe/perhaps” contingencies on Sean’s original thoughts. It strikes me that human beings overcome “what if” problems of profound magnitude each and every day, simply by being human beings. The laws of everyday sciences and math propose numerous risks for drivers of automobiles. Yet we don’t suffer the debilitating argumentative deadlocks that keep us from accepting that the risks are part of the way we need to transport ourselves through time and space. We get into the autos and go forth, in very much the same way our ancestors got on horses, rode in wagons, or reined chariots.

    Likewise, we can say, with 100% certainty that the solid table will not levitate, but will stick to the floor.

  19. Eric says:

    Slightly tangential question:

    So, if all everyday phenomena is satisfactorily explained, what justification is there for further basic physics research beyond scientists’ own intellectual understanding?

    Not to say that I dislike physics research; I’m starting my PhD in theoretical astrophysics next fall. But I wonder if we’re past the point where we can really say we’re providing a tangible benefit. A lot of people trot out the argument that we had no idea lasers would be useful and now we can’t live without them, but can we really make the same argument about dark matter and dark energy?

    *I* definitely want to know what dark matter is, but I don’t know if there’s any benefit to us finding out other than our own satisfaction.

  20. Sam says:

    Cody said, “I also don’t understand why people find consciousness so mysterious…”

    Perhaps because they ask questions like “Is my perception of red the same as yours?” or “Why does light of wavelength 680 nm give rise to that (red) perception, while light of wavelength 480 nm gives rise to the perception of blue, and not the other way around?” or “Is the set of color perceptions I’ve already seen all that could be, or could some technology create an entirely different one?” It’s not at all obvious (to me) that answers to these (everyday?) questions will one day be provided by the standard model, GR, QM, or even SUSY. It may really require zylbot theory. [And please substitute “quale/qualia” for “perception/perceptions” if you prefer that jargon.]

  21. Ricardo Massaro says:

    @Pieter Kok

    Suppose we’re able to build a quantum computer with only our current understanding of QM (i.e., with no new fundamental physics). Am I to understand that our current understanding of QM doesn’t “explain” how that quantum computer works (even though it was *built* using QM) just because it can factor integers exponentially faster than anything we can do classically?

    That doesn’t seem a very good definition of “explanation”.

  22. Pieter Kok says:

    @Ricardo

    Our quantum computer can indeed behave in predictable (and useful) ways, such as in the case of factoring large numbers. But suppose that the quantum computer is producing some output based on what we feed as input, and we wish to work out the specific algorithm that is being computed. Even though we completely understand the underlying laws of quantum mechanics, and we built the machine ourselves, since the problem of characterizing the algorithm is intractable we cannot have a complete understanding of the patterns that emerge in the output, even in principle.

  23. Ellipsis says:

    For the two everyday phenomena of the number of macroscopic dimensions we observe (i.e. 3+1), and the equivalence of inertial and gravitational mass, it is not at all clear that those two everyday phenomena should be just placed there by hand into axiomatic GR as they are presently, or if they are perhaps ultimately due to quantum gravity that we don’t understand as of yet. So, although I of course agree with you for the vast majority of everyday phenomena, there are those two exceptions to your statement that, if you maintain that your statement definitely holds even for those, you are not necessarily in agreement with physical consensus, which is that we don’t know yet.

  24. Sean says:

    Cosmonut– The possibility of new long-range forces that respond nonlinearly to sources — i.e. were more than n times stronger for n particles than for one particle — is probably the most plausible loophole to the “we know all the forces” claim. But I don’t know of a way to make it actually work, though I’ve tried. It’s relatively easy to do the opposite — screen forces non-linearly — but sourcing them is not so clear. Of course, there’s zero evidence for such a phenomenon, but it’s worth thinking about.

    bittergradstudent — If gravitational waves are part of your everyday life, I’m not sure why you’re so bitter. That would make me a very happy grad student!

  25. Cosmonut says:

    Hi Sean, thanks for your reply @24.

    Your posts on this subject got me thinking of this great passage I’d read in the Feynman Lectures and I managed to locate it today (its at the end of Chapter 41), and I reproduce a bit of it here.

    “The next great era of awakening of human intellect may well produce a method of understanding the qualitative content of equations. Today we cannot.
    Today we cannot see whether Schrodinger’s equations contains frogs, musical composers, or morality – or whether it does not. We cannot say whether something beyond is needed, or not. And so we can all hold opinions either way.”

    Thanks for the thought provoking topic.