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.
@69 John — the “problem” of free choice was adequately answered by Hume nearly 300 years ago. Basically, the solution is that the sort of free will we actually have doesn’t contradict determinism, let alone the looser regularity of quantum mechanics. We do things for a reason. If you really think behavior is totally unpredictable, you’re deluding yourself. The fact that some people still believe in acausal free will is no more problematic for modern physics than the fact that some people still believe in ghosts.
@74 Maurice — quantum computing is not based on anything beyond the standard model.
@72 CIP. I see where you’re coming from. I do think though, it’s very different to claim that there’s no conflict between chemistry and physics for example now than it was to make the same claim in 1870 or whatever. 19th century physics didn’t even make heuristic predictions about what chemistry could plausibly be like, wheras modern physics predicts lots of things about chemistry even if the details of complex molecules are worked out empirically. I also don’t think most late 19th century physicists shared Kelvin and Michelson’s view that the future of physics lay in ever more precise measurement of the principles we already understood, while I think most prominent physicists since Feynman would agree with what Sean is saying here.
@76 Ray, can you give a definition of free will that is compatible with determinism?
A consequence of QM is the free will theorem. In loose terms: no matter how you define ‘free will’ if QM is valid, free will can exist only if elementary particles have it as well. The conclusion seems inevitable: our current laws of physics (QM+GR) simply are in contradiction with our day-to-day experience of free will.
Sean: “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.”
Can you give examples please?
A definition of free will that is compatible with determinism (so easy that even I, a layman, can do it): free will is the illusion that if your life were lived over in exactly the same way (including a blank slate of memory at birth), and all external events transpired in exactly the same fashion, that you would make different decisions. Thanks to the random, acausal nature of quantum-level events in this, and in any good universe, such an experiment is not possible even in principle, so this illusion is free to maintain itself in the minds of those who would like to believe it.
@78 Hey, John, here’s a suggestion: read.
Sean’s last paragraph starts with:
“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.”
But if that’s not enough, you can also go to his original post (September 23rd) and read:
“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?””
Let’s not just ask the same (already answered) questions over and over again…
Btw, great sequence of posts, Sean. I can only agree.
Hey nebur, that is not a very helpful answer.
I hoped Sean had something more convincing in mind. All the examples you quote would a century ago have been classified in the category “the detailed way in which everything plays out”, but not as a contradiction to “the underlying principles”.
@79 JimV, that I would not call a definition, but rather a denial of the concept of free will.
That’s a great one: mass! Every other physical measurement has been defined in relation to a constant.
Q: How fast am I going?
A: Some percentage of the speed of light through a vacuum…anywhere.
Q: How much mass do I have in zero gravity.
A: Some multiple of a piece of platinum (with a little bit of iridium) that itself is losing a little bit of mass all the time. IE, I don’t know.
So…how well do we understand the physics of everyday life if we can’t define the kilogram unambiguously?
@John
“can you give a definition of free will that is compatible with determinism?”
Free will is the ability to do what you want to.
This in more specific, but by no means completely rigourous terms implies that your mental process can be divided into subprocesses that
1) form desires (this need not be done randomly, and indeed it is not — pretty much everyone wants food shelter and sex although it’s more complicated, since we’re highly social animals)
2) model the likely result of possible actions (possible in the sense that causing them to happen would not require any changes to your anatomy outside of the brain)
3) compare the results of possible actions with the results of the desire generation process and pick the one with the best fit.
As far as Conway’s free will theorem — it rather begs the question in that it assumes free will has something to do with indeterminism.
For more info read some Hume, some Dennett, or the wikipedia entry on compatibilism.
@ Thanny
Since we are talking about everyday problems, what are the fundamental components of that day? Is it a second? a minute?
That would be like asking for the fundamental components of a table and being told it was centimeters.
>>1) Those that don’t really know the underlying physical principles currently understood, and how they generally apply to everyday life.
Which theory did I miss that defines the fundamental unit of time?
>>2) Those who are ignorant of the history of science, and don’t appreciate just how many complete and utter mysteries have been solved in principle or practice over the past several hundred years.
The history of science reveals that one of it’s greatest thinkers worked in a patent office and was not dependent upon the support of ‘respected scientist’ to pay the rent. Large stable communities with histories are great for many reasons but radical innovation is not usually one of them. wikipedia: skunkworks
>>3) a third category (existence in someone’s imagination is not sufficient evidence for existence in reality)
The best part of any Phd program is when the student realizes that it is their job to create reality. A reality that springs forth from imagination.
Science has made a lot of progress but everyday magic remains. The definition of the relationship of time to the collapse of the wave function of the universe will probably require new physics. It is hard to say it will, it’s hard to say it won’t. However, if you shut yourself off to the question you certainly won’t be the one to come up with the answer. It is a bit unsettling how many people are jumping at the chance to stop asking questions.
@Alan: You’re certainly right that e.g. “remote viewing” would qualify as a violation of everyday physics if it were actually happening. But remember that in the world of science, open and repeatable results and consensus in the community is what is important at the edge of science. And these remote viewing experiments by the CIA definitely do not meet either of those criteria. That does not make them wrong, but it means that there is no reason to worry about them until there is enough repeatable evidence for the scientific community to take such results seriously. Even moreso given that some very prosaic explanation (e.g. when statistically examined, “remote viewing” is generally no more accurate than someone just guessing based on general information about some location) is quite possible.
@Pete: Emprically, it is clearly not self-evident based on the number of comments to this and the previous post…
@MT-LA
That would be easy enough to change to ‘some multiple of the mass of the proton’. My understanding is just that contemporary measurements of the standard kilogram have a lower error than contemporary measurements of Avogadro’s number, and so the kilogram is a better standard for now.
NIST and its European eqivalent are actually looking for a physical definition of mass as we speak.
@84 thanks for the reply, Ray.
Ray: “As far as Conway’s free will theorem — it rather begs the question in that it assumes free will has something to do with indeterminism.”
I don’t think so. The free will theorem is just a reflection of the fact that in a universe that evolves in a way that is described by a unitary transformation in a Hilbert space, no free will can exist (unless you define free will as something that even an elementary particle posseses).
Sean puts forward the challenge: “you would have to point to something the brain does that is in apparent conflict with the Standard Model or general relativity”. My response is: “freedom to chose”. Isn’t it obvious that free will is in conflict with unitary evolution (= very foundation of standard model)?
Ray: “For more info read some Hume, some Dennett, or the wikipedia entry on compatibilism.”
Compatibilism, libertarianism, etc: it’s all philosophical waffle. And that is my point: as long as things like free will remain in the realm of pre-enlightenment pseudo science, and are not successfully tackled by science (physics), we haven’t understood a thing about it.
Source: Harvard professor Wendall Furry: “[In the Copenhagen interpretation of quantum mechanics] the existence and general nature of macroscopic bodies and systems is assumed at the outset. These facts are logically prior to the interpretation and are not expected to find an explanation in it.”
Two clouds on the physics-explains-everyday-life horizon:
1. the existence and general nature of macroscopic bodies;
2. the variety of experiences associated with human consciousness.
Other than these two clouds (and assuming masses and coupling constants to be God-given), modern physics really does seem to completely explain the everyday world.
@john
My definition of free will at least implies divisibility, which elementary particles do not possess.
And yes, conway’s free will theorem as an argument against compatibilist free will does in fact beg the question. To quote the wikipedia page:
“The definition of ‘free will’ used in the proof of this theorem is simply that an outcome is ‘not determined’ by prior conditions, and some philosophers strongly dispute the equivalence of ‘not determined’ with free will.”
You ask “Isn’t it obvious that free will is in conflict with unitary evolution (= very foundation of standard model)?”
No. The very existence of the compatibilist position implies that this statement is not obvious.
You further state: “Compatibilism, libertarianism, etc: it’s all philosophical waffle. And that is my point: as long as things like free will remain in the realm of pre-enlightenment pseudo science, and are not successfully tackled by science (physics), we haven’t understood a thing about it.”
You make a philosophical argument against the sufficiency of the standard model and then dismiss philosophy? and then you claim Hume is pre-enlightenment? Look, I’m not a huge fan of philosophy as a discipline — I think philosophers as a whole have been very bad about discarding bad ideas (libertarian free will being amongst them.) Nonetheless, a lot of good ideas have come out of philosophy. In particular you don’t need to know squat about physics to figure out that divine command theory, platonic idealism, libertarian free will etc. are non-starters. Nonetheless, people both within and especially outside of philosophy continue to expound these bad ideas as arguments against physics. Anyway, I don’t think you can dismiss philosophy. At least you need to recognize when the argument you are making against physics is philosophical rather than empirical.
Sean, I’m not sure if this is answered in the previous 90 comments, but it didn’t seem to be, so I’m asking the question. As far as I can tell, you are trying to distinguish between:
(1) the macro-level physics that is understood by some (maybe still very complicated) equations but maybe not understood as a phenomenon (i.e. turbulence), so that, in theory it is possible to still understand the phenomenon, and
(2) the physics where we don’t understand what equations need to be used, so it is still not possible to even understand in theory what is going on.
You are also (I think, but again am not sure) saying that everyday physics falls completely into the first category, not the second.
If my understanding of what you are saying is true (and if it isn’t, please tell me), then I think a few parts of everyday physics (which sometimes seem like engineering questions and not physics at all!) fall into the second category, not the first. The three that immediately come to mind are:
(a) shock waves
(b) friction and
(c) fluid flow around sharp corners.
I know the standard answer to all of these is that “we can just use such-and-such equation and then numerically solve, blah, blah, blah” and that it seems that the question is actually part of the physics (1) not physics (2).
*Except* that as far as I can tell the underlying equations are experimental assumptions, (like saying all shear must be linear), not built from sound physics, and as such are still not understood. This is different from the (for example) turbulence question, which is really a statement of “using a particular set of continuum equations, we can crank the parameters into murky and interesting territory.”
I’m not trying to troll here, but am curious if you (or others) could explain the underlying (and hence totally well-understood, if possible) physics behind those three things that apparently I’m totally unaware of 🙂
Thoughts?
Hi Erik @ 86
Just to answer you, I’m afraid this subject gets quite complicated! This is from the perpective of a CIA officer (engineer):
http://irva.org/library/articles/kress-pii.html
The postive result of the magnetometer test on Ingo Swann (when he remote-viewed the device) is mentioned in paragraph 8. He concludes near the end of the article that although the reproducibility is poor, “experiments have successfully demonstrated abilities” … “but have not explained them”.
The International Remote Viewing Association seem to be a serious and very current group:
http://irva.org/conferences/speakers/index.html
I personally think it goes like this. There are those (personal, research, military – “can do” types as the military are – I have known several) who have persistently investigated this phenomenon, formed groups, and tentatively found it real. The data is really in, although sporadic. And there are others who quite innocently don’t know about it, which is of course quite OK or do know and have an agenda, maybe personal or sinister, and criticize from these perspectives.
But overall, from what they are saying here, it looks quite real to me.
@bittergradstudent:
I’m going to have a hard time making my point on this one because I dont have the technical terms on hand, but:
Do you agree that all other measurement units (meter, second, volt, etc) have been defined in terms of invariant properties of nature (eg, the speed of light in a vacuum)?
Do you agree that, as of right now, the NIST and others have no definition of mass that is traceable back to invariants of nature?
The current standard might be very good, and the powers that be may be looking for a better standard, but I’m talking about physics. And if a basic property like mass can’t be defined unambiguously, then I think it’s presumptuous to say that “the underlying physics of everyday life are completely understood”.
“Do you agree that, as of right now, the NIST and others have no definition of mass that is traceable back to invariants of nature?”
No. There are plenty of available ways to define mass that are traceable back to invariants of nature. As it stands however, if we define mass in such a way we can only measure the mass of things to the nearest 50 parts per billion, while with the current definition by artifact we can measure masses to the nearest 20 parts per billion. This seems hardly a concern for fundamental physics.
For Pete: Maybe you don’t need the machine to filter out Sean’s posts because they waste your time. Maybe, instead, it would be beneficial cranial exercise to save your valuable time by recognizing posts by Sean and not reading them.
OTOH, I am surprised by the objections that were raised to your first posts, and some I see in comments to this one.
While I am not a physicist, I follow it with interest for 45 years, and just enough knowledge to get most of it. What is most interesting to me is how easy it is for supposedly knowledge people to (almost purposefully) misunderstand the thrust of your assertion. How can anyone defend their pet quantum/micro niche when you clearly stated these articles are about our real, humanly observable world.
Sure we know there are laws that appear contradictorily to what we humans see. But, it’s equally clear that they operate at a different level of observation. It’s impossible to pretend you have proposed that all knowledge has been discovered … why to otherwise knowledgeable imagine that what you assert?
Tempest in a teacup. Nice articles Sean … Those inclined to stroke their own egos, need to go on a … er … trip and experience the real world (maybe a reading comprehension course wouldn’t hurt either).
Ray: Thanks for the response.
“There are plenty of available ways to define mass that are traceable back to invariants of nature”
What is one of the ways? (No, I’m not asking for the full process…just the name, or the term, or whatever. Something that I can look up on my own so that I dont waste your time) Of course, if you feel like going into depth about one of them, I won’t begrudge you the chance.
“[20 ppb] seems hardly a concern for fundamental physics.”
So fundamental physics doesn’t care about an error of 20 parts per billion? That seems odd, but I’ll be satisfied with that answer unless a physicist objects.
@MT-LA
The intuitively easiest way is to define it as the mass of a certain number of atoms of carbon-12, say.
The leading candidate though is the “electronic kilogram” which is measured by a multistep process.
1) figure out the laboratory value of gravitational acceleration, g
2) measure the weight of an object as compared to the magnetic force generated by a known current at a known distance. This is in turn compared to physical standard resistors and voltage sources.
“So fundamental physics doesn’t care about an error of 20 parts per billion? That seems odd, but I’ll be satisfied with that answer unless a physicist objects.”
measuring constants is more a concern for experimentalists than theorists.
Nebur,
I don’t think you or Sean are applying his criterion fairly. What aspect of Newtonian physics is contradicted by the non-collapse of tables? 1910 is a bad example, since quantum contradictions in atomic theory were already in the air, but even by 1910 there was no good reason to think tables should spontaneously collapse – for that you need the Rutherford atom. If you go back 120 years (or 150 or 300 years) , there is no aspect of everyday life that contradicts Newtonian physics
I understand what you are saying. I remember in school when I learned that the periodic table was full and complete. Sure, people can tack on new elements on the end, but you never see those elements in real life. It was a hard fact to accept that everything was made of a finite number of known things. That is stunning, amazing progress.
On the other hand, there are still major parts of everyday physics that are labeled “Thar be Dragons” on the maps. That does not mean that we don’t understand the fundamental governing laws (as you point out clearly and repeatedly), but it does give me pause. You write “…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.” I am just not willing to make that leap, I guess.
“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.””
That’s wrong. Quantum mechanics is the everyday. The classical universe we see is in fact an entirely quantum mechanical universe – gravity included – operating quantum mechanically at every level.
Back in 1900 they knew perfectly well that their laws didn’t explain everything, but they just classified the things it didn’t explain as outside the domain of discussion, and regarded the rest as an approximation that was good enough that you could call it ‘the’ laws of physics. We have better approximations today, but are in fundamentally the same situation. We know that quantum mechanics and general relativity are inconsistent. We can see everyday effects of both of them. (Like gravity and computers.) We have approximations that are sufficient to predict/calculate anything we want, but we don’t actually know what the rules are.
We see quantum mechanical effects like falling bricks appearing in a definite place and at a definite velocity (not classical – there are no classical effects), and need to explain why we do not see a blurry superposition. If the wavefunction really collapses to a definite point position, it’s subsequent velocity would be close to lightspeed – so clearly it doesn’t collapse all the way, and we can directly observe that fact. This is just the same sort of failure as the electrodynamic collapse of atoms – if you follow the theory to its ultimate conclusion, it makes no sense, but you can get round that by not following it down that path, and then declaring that the parts not marked ‘out of bounds’ are a complete explanation of the everyday.
It is “closer to reality” in the same way that epicycles are closer to reality than perfect circular orbits.