# When Sean Carroll says "The Laws Underlying The Physics of Everyday Life Are Completely Understood" , is he being click-baity or is he correct? [closed]

I read three posts of his on his blog:

The Laws Underlying The Physics of Everyday Life Are Completely Understood

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

One Last Stab

Now, I know that understanding the underlying laws of physics does not mean that we know entirely how those laws work together to form bigger systems like say a human being. I know that is not what he means.

But, his point seems to be that, if there is some unknown basic law of physics that we have not discovered, then those cannot relevant at time and size scales that affect everyday life.

How correct is he in this assertion? Isn't there always a chance that we are missing something, and maybe in a hundred years we will discover this?

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– rob
Jun 14, 2021 at 18:31
• If you google "physics in 9 lines" you will find an even more radical version of Carrol's point of view. Nov 30, 2022 at 18:58

In my opinion, Caroll's point is that we have solved everything wrt. everyday phenomenon and then some. Paraphrasing him from the linked article

1. by solved he means knowing the underlying laws: "In particular, taunting “you’re no grandmaster!” is not actually a refutation of the claim that I know the rules of chess".

Though by so knowing one declares triumph over all everyday phenomena, as you and he suggest, explaining all but the simplest systems as emerging from these laws is another matter altogether. Yet we are confident that we can.

1. by everyday life he means phenomenon "you see happening in your kitchen on an everyday basis."

But, his point seems to be that, if there is some unknown basic law of physics that we have not discovered, then those cannot relevant at time and size scales that affect everyday life.

In my opinion, his essential argument boils down to the fact the new physics - and by this he means new underlying fundamental laws - must occur at quantum or cosmic scales both of which are not part of everyday life. Everyday life is most affected by gravity and electromagnetic forces, and is the oldest and most probed regime. It would be a surprise if a new law of physics was discovered hidden in everyday activities that we have missed so far. Moreover, one may claim that everyday life was completely 'solved' by Newton and Maxwell's seminal works.

Isn't there always a chance that we are missing something, and maybe in a hundred years we will discover this?

Yes there's always a chance. But Caroll deems this lack of certitude "metaphysical" and "not a criterion that is useful in science", and with good reason. Our probe of reality - experimental observation - has yielded newer and newer insights over the past $$100+$$ years since Maxwell, illuminating a hitherto unknown understanding ranging from that of stars to atoms to GR gravity. But never has such an insight improved the fundamental theory that is most important to everyday phenomenon. Everyday life has remained classical and Newtonian for those $$100+$$ years and that suggests, it would stay so. In my opinion, he calls this the "conventional scientific measure" and is the source of his confidence.

@JoshuaLin piqued

the problem lies more in how our conception of "everyday life" will expand in the future with developments in technology and stuff like that; maybe.

Consider this: quantum physics has already revolutionized our everyday life: electron microscopes, transistors and all of the resulting IT and telecommunication, optical fiber, MRI machines, the nuclear bomb and so on. Does this mean Carol is wrong to claim that everyday life revolves around classical interactions and has little scope for new fundamental discovery?

Not at all for even though these marvels of quantum physics have indeed affected our daily lives, that is a philosophical aspect and not a Physics one. Though devices or technologies may operate QMcally, our interaction with them is still vanilla old classical - we don't drive the electrons in a tunneling diode or consciously flip the spins of protons during an MRI or police light to undergo total internal reflection at the boundary of an optical fiber while using the internet.

In the same vein, even if future innovation brought currently novel and laboratory phenomena like superconductivity into the palms of common folk, their interaction with them would still remain classical, explainable and solved. The new laws discovered if any, would stay hidden and operate silently, within those new-fangled devices of these future denizens.

• " "In particular, taunting “you’re no grandmaster!” is not actually a refutation of the claim that I know the rules of chess" " I was definitely not taunting that. My point was the reverse of that, i.e. saying "i know the rules of chess " is not a refutation of " You are no grandmaster " Apart from that, i agree with most of what you have said. Upvoted Jun 13, 2021 at 12:56
• @silverrahul sry I didn't mean to imply you were taunting. Those are his words, just quoting them. Everything in double quotes are Carol quotes Jun 13, 2021 at 12:58

This statement is nothing but a rephrasing of the well-known view that physics is "remarkably successful". We have to deal with the cognitive dissonance, that although we can compute measurable quantities to 10 or so significant digits with our theories, and like 99.9...% of the phenomena in everyday life apparently can be explained just with classical electrodynamics and quantum mechanics (not taking into account a possibly huge set of so-called "emergent" phenomena), the theories don't always make much sense, mathematically, at least as we know today.

On the other hand, the desire to gain an in-depth understanding about everything we do successfully, is psychologically understandable, but it is expendable in the evolutionary sense. People have built hand axe, archimedes's screw and cast iron, long before we even remotely understood what's going on.

It is perfectly possible that the standard model of particle physics will once be understood as the hand axe of current culture. Or maybe not. It is difficult to say without being able to look into the future. This is why I have stopped reading physical self-help-type books and authors.

I think you answered your own question. "Isn't there always a chance that we are missing something, and maybe in hundred years we will discover this?" Sure, maybe there's something missing at scales that affect humans during everyday life, but if it'll take 100 years to find, then clearly this effect isn't affecting everyday life.

• " but if it'll take 100 years to find, then clearly this effect isn't affecting everyday life. " Surely, that cannot be an argument for what affects or does not affect everyday life. There are lot of discoveries that affect everyday life, that took more than 100 years to find. Jun 13, 2021 at 6:49
• Sure, most discoveries took about 14.7 billions years to find, if you count from the start of the universe. But you're counting from now, right?
– WAH
Jun 13, 2021 at 6:52
• that is not how i am counting. My point was that , does how long a discovery took to make , determine how fundamental those discoveries are to the physics of daily life ? Jun 13, 2021 at 6:59

The interesting thing here is that the underlying physical laws that can (in principle) explain everything we come across in everyday life are fairly simple and can be understood by processes inside the squishy lumps of cells that we call brains. Beyond that, this assertion doesn't tell us very much - I totally understand the underlying laws of chess, but that doesn't make me a grandmaster.

• I think that is missing the point. Like i said, " I know that understanding the underlying laws of physics does not mean that we know entirely how those laws work together to form bigger systems like say a human being. I know that is not what he means. " So, in the chess analogy i am not saying science has become a Grandmaster, nor is Carroll claiming that . But he is claiming that science has understood all the underlying laws of chess. This is the assertion that i am questioining Jun 13, 2021 at 8:04
• @silverrahul If you are questioning Carroll's assertion then you need to provide a counterexample - something in everyday life that you have grounds for believing cannot be explained by the known laws of physics. Otherwise we are just swapping opinions, which may be fun but is not within the scope of PSE. Jun 13, 2021 at 8:15
• That is again missing the point. But , you are right, where I am disagreeing with you is more a matter of the philosophy of science, rather than the science itself. Jun 13, 2021 at 8:24

Magnets and QLED and in the future perhaps room temperature superconductivity and quantum computing involve quantum mechanics. No one can say that QM is completely understood. However, there is nothing in my daily life that requires 'new physics'. In this sense I agree with the statement. My opinion might have been different if I worked at CERN.

In my opinion the statement by Carroll is an empty statement.

Physics is in the following unique position: classical mechanics has such a large realm of validity that even though it has been superseded it would be absurd to stop using it.

Be that as it may: it is agreed that the validity of Classical Mechanics is to be thought of as arising from the fact that Quantum Mechanics subsumes Classical Mechanics. It is agreed that the properties of Classical Mechanics are to be thought of as emerging at macroscopic scale from underlying Quantummechanical processes.

(In the context of this answer I group Maxwell's equations under the larger category: 'Classical mechanics')

Compared to Quantum Mechanics Classical Mechanics has a smaller realm of validity. But as stated: that realm of validity is so large that it would be absurd to stop using classical mechanics.

And of course it goes farther than 'still using it'. Classical mechanics is taught to students of physics, and students must master it, because classical mechanics offers a unique stepping stone. Still close enough to everyday life that it can be understood intuitively, but it prepares the brain for the level of abstract thought that is needed in order to learn quantum mechanics.

Comparison:
Before the introduction of Newton's laws of motion and the introduction of the inverse square law of gravity there were Kepler's three laws of celestial mechanics.

Newtonian mechanics is the deeper theory; Kepler's laws of celestial mechanics follow logically from Newton's-laws-of-motion and the inverse-square-law-of-gravity.

A statement along the lines of: "Since we have Kepler's three laws we have that celestial motion is completely understood" is an empty statement.

Once the validity of newtonian mechanics became clear it was also clear that Kepler's three laws constitute partial understanding only.

So I would paraphrase the statement by Sean Carroll as follows:

"We have complete understanding of a paradigm that we know constitutes partial understanding only: Classical Mechanics.

Dark Matter holds the Galaxy together and is not yet understood. If you consider living in the Milky Way part of everyday physics, then this would be an exception to his statement.