I adopted this exchange between Penny and Sheldon as the canonical response to the people who boldly claim that I shouldn't understand the discipline XY. A real physicist understands the Universe and everything important in it – and, as an updated version of Sheldon, I also know who is Radiohead! ;-)
And since the kindergarten years, I felt certain about the unity of knowledge – about the statement that the separation of the knowledge into individual scientific disciplines is ultimately a fuzzy and fundamentally unjustifiable construct, pretty much a social convention. And on top of that, it's obvious that something that was termed "physics" is the most fundamental level of knowledge from which other disciplines may be deduced.
In fact, physics may have "a theory of everything" (TOE) and I am clearly one of those who think that a TOE does exist and some of us largely know what it is (I had to remove "we" from this sentence because such a word is often misinterpreted and abused: I am talking about some 2 thousand people, not 8 billion people). But this answer is the outcome of rather nontrivial, "much harder than philosophical", thoughts and research. Even if a TOE didn't exist, science would still have a hierarchy of explanations and at every moment of the evolution of science, some parts would be more fundamental and axiom-like than others – and those would be the parts that the physicists or the people who "organize their thinking in this way" (philosophers using mathematical principles and empirical data) are naturally focusing on.
Sciences (and even more practical human activities) were always concerned with events in the spacetime and physics, from its Galilean and Newtonian modern reset, dealt with masses and forces in between them. After some advances, it has significantly changed its understanding of the "structure of matter" and the "character of forces" – as well as the relationships between matter, forces, and the spacetime itself. Point masses were soon replaced with the continuum and fields. Special and general relativity have mixed the space and time and allowed both to be curved. Predictions were switched to observers' probabilistic predictions by quantum mechanics. And so on.
But as far as I can say, we're not considering elementary particles and forces important just for their own sake. They are important because they affect lots of other things – well, they affect everything. Chemistry is applied atomic physics (application of electromagnetism and quantum mechanics to electrons and nuclei). Biology is applied chemistry (plus physics). Neurobiology is a special part of biology dealing with some specific, more complex objects. Psychology is a phenomenological attempt to study neurobiology by methods that are accessible to relatively stupid people (psychologists). Psychiatry is a special case focusing on the situation when these complex objects malfunction. "Gender sciences" etc. are an even more special subfield of psychiatry because "gender scientists" are even sicker than the average patient in a mental asylum. And we could continue.
Everything may be reduced to physics, to the amazing discipline largely built by the old (and mostly dead) white straight men (did gays contribute more than 4% of physics or less?).
All the evidence indicates that this nontrivial "reduction of everything to physics" is possible in principle and some people are OK with that. But I think it's true not just in principle. In most cases, it's true in practice, too. A real Sheldon-like physicist is really looking at the world throught the optics of physics of molecules, physics of trains, physics of science-fiction movies, physics of the Texan laws, and so on. A Sheldon-like physicist is the 21st century's updated and refined version of the old concept of a polymath. (Thankfully, the bastards gave him and his spouse the damn Nobel prize at the end.)
The "old polymaths" became impossible because the amount of knowledge grew too much. There were times when a smart person could have read and understood "all books ever written and available to his civilization". She or much more likely he could have contributed something to the knowledge and you had a polymath. Thomas Young (1773-1829) and especially Hermann von Helmholtz (1821-1894) are mentioned as some of the "last polymaths".
Things are harder in a world in which approximately ;-) 129,864,880 book titles have been published. It's stupid to try to read all of them. A person attempting to read all of them wouldn't be a polymath or the smartest person on Earth – she would be a lunatic. It's impossible and counterproductive to pay attention to everything that the other people have written down – even though tens of thousands of these books may still be claimed to be "really essential" for a true modern polymath.
But that's where the virtues of physics help, too. A sensible physicist knows that the fundamental wisdom of the world isn't really about the people and their views; almost all of the social stuff is just unimportant noise. It's about the fundamental laws of Nature. And they didn't grow "extensively", at least not too much. Instead, they have fundamentally deepened, especially when it comes to the mathematical traits that the new polymath must understand.
I said that many people agree that other sciences may be reduced to physics in principle. That's nice but a true modern physics-like polymath actually tries to think and live like that. A physics degree or another label doesn't guarantee that the person is good at everything, of course. In many cases, he or she is not. So I was recently stunned to see that a physicist whose IQ I routinely estimate to be above 180 may approach politics indistinguishably from an IQ-75 far left troll. There seems to be an "inconsistency" in the quantification of the IQ but I still think that the mathematics-related IQ is the real one while the dumb political views are just his intelligence-unrelated "idiosyncrasy".
But the reduction of the other questions to physics isn't just about the logical implications that exist in principle, about the importance of the fundamental laws of physics. This reduction is also – and maybe especially – about the physicists' methods of thinking and looking for the truth. A real physicist uses a combination of the "invention of the hypotheses", "their impartial testing and comparison using the empirical data", and maximally frequent "calculations reflecting the previous knowledge, especially that of some major brands of physics", wherever it seems possible, with the degree of precision, accuracy, and rigor that seems adequate to the given problems.
Even with this description and even when the physicist does things very well, he may end up doing "very similar things" as the other, "non-physicist", leaders of that field. But even when it is so, the physicist usually adopts the "existing methods of that other field" after he or she checks that smarter, more direct, more accurate, or more physics-like methods don't really work well (while the people in those fields just adopted these axioms because they were told to adopt them). And in many cases, the physicist's approach has a far higher chance of a non-random game-changing advance towards rationality and deeper knowledge.
Needless to say, the very fact that a true physicist is smarter (and uses more solid methods of reasoning) than other scientists has been considered "politically incorrect" decades before the existence of two sexes and similar things became "politically incorrect". It was politically incorrect for a simple reason – there were too many people who weren't quite physicists (or appropriately smart) and they wanted to outlaw any hints that they're not really in the "intellectual prime league".
But for centuries and up to 2000 or so, there were always many influential enough "true physicists" – at the global level but also at every good enough university etc. – who considered the superiority of the physicists' thinking to be an essential building block of their world view. But while the omnipresent malignant tumors of the political correctness were growing in recent years, the cardinality of the set of overt, self-confident "true physicists" has dropped to homeopathic levels. Of course, I might ask: Who is the third (if not second)? ;-)
In 2020, we are simply living in a world that is constantly bullied by mobs composed of angry filthy inferior people and certain vital groups underlying the health of our civilization were basically driven to extinction. I am being constantly reminded of this fact e.g. when I interact with some other people, including professional physicists. A huge fraction of them if not "almost all of them" have drunk Kool-Aid and they have agreed to be just "Fachidiots" who are answering just some special, impractical questions – while everything else should be answered with the approaches that the non-physicists favor. In fact, it's worse than that: a similar majority seems to believe that the "authorities in those other fields" should beat the physics-like evidence, calculations, as well as common sense. It seems that even many physics PhDs are on the side of Penny in the discussion with Sheldon above! Like millions of laymen-viewers, they may have even missed an important point of the 12 years of The Big Bang Theory – that Sheldon is pretty much always right on the money.
This disappearance of the physics-like thinking about "other topics" seems obvious in many interactions. For example, I ask an innocent practical question: When I take a regular vacuum cleaner (with a cloth bag) and attach a Covid-era face mask to my face, are my lungs increasingly protected against some dust? Isn't this new know-how another nice silver lining of the Covid hysteria? Or is it just a placebo effect?
I thought it was clear what I was asking and why. The basic fact is that there is some dust in my apartment, your apartment, and every apartment (although the masses differ quantitatively) and some of the dust unavoidably circulates when you're vacuuming the floor. The purpose of the vacuum cleaner is to move the dust from one place to another – ideally from the floor (or the air in your room) to the trash can. To make things worse, it's normal to empty a bag and you get another circulation. Some amount of the dust gets to the lungs. These are normal processes, I think that most people who have done some work of this kind realize that they have done a nonzero harm to their lungs and they know it's silly to try to avoid the dust "perfectly".
OK, some apparent sellers of vacuum cleaners have immediately emerged. I surely need to buy a new vacuum cleaner if I observe any dust that circulates while the vacuum cleaner is on. What? WTF? ;-) I didn't ask whether I should buy a new vacuum cleaner; if something, I wanted to make a progress with a $1 face mask. I asked whether it has any benefits to wear a face mask during this work. Also, I didn't expect a discussion about better filters. HEPA filters are a standard initiated in the physicists' Manhattan Project – which needed very clear air at some points – and the condition is that 99.97% of particles of diameter 0.3 microns must be caught (and the filter is expected to catch even more of the higher particles but it usually catches some smaller ones, too).
That's great but it wasn't the "branch of physics" which I considered (and consider) essential for the question. Whether a particle gets through a hole is also an aspect of physics – and an important task in the IQ tests at Idiocracy. But the HEPA-size particles are so small that they largely circulate in the air at all times. I am convinced that the actual dust whose circulation increases during vacuum cleaning is composed of vastly greater particles. A human hair is between 40 and 100 microns thick. This is arguably closer to the size of particles that are found in between the hair on the floor, too.
So I thought that I was really asking a question about aerodynamics, about the circulation patterns of the air during vacuum cleaning and how they're impacted by the face mask. The relevant, heavy enough particle of dust feel a substantial force of gravity and they probably don't want to fly "too high" for "too long". But because every vacuum cleaner causes some air circulation, there is always some amount of dust that can circulate without being sucked by the gadget. If the air gets to my nose around the face mask, don't the (heavy enough) dust particles "give it up" before they get to the nose if they have to circumvent the face mask? At any rate, it seems clear to me that the speed of the air at various points greatly matters for the answer. It seems like a self-evidently complex question and a measurement could be the most feasible way to find a trustworthy answer.
But some people were quick to reduce the question to the quality of filters – and basically to a single quantity, how large particles of dust they mostly catch. This one-parameter thinking (one parameter is the particle size) looks like an utterly non-physical thinking about this complex problem. I think that this is how stupid bureaucrats or people without any physical training start to think about these things: "Dust in the air translates to filters. Filters translate to particle size. Particle size translates to some EU regulations about filters." And so on. Please, give me a break. These sloppy "reductions" are the opposite of what a physicist wants to do. A physicist wants to reduce the problem to the laws of physics, not to bureaucracy or superstitions. Some laws of aerodynamics and the Maxwell-Boltzmann distribution may be useful.
Needless to say, a nearly identical non-physical thinking was widespread during the Covid-19 hysteria. Someone spread the ludicrous political meme saying that "everything is about the social distancing" and all the brain-dead people became unable to rationally think about absolutely everything. Like zombies, they were designing ways to prevent people from human and economic interactions (the more economic and emotional harm, the better) – which had pretty much nothing to do with the (medical) problem. In particular, all of them assumed that the "viral dose" didn't matter, and neither did the location of the viruses relatively to droplets of water, the substrains of the virus, and other things.
But the size of the saliva droplets, their speed, surface tension, distance and even altitude of the trajectory that they need to overcome for an infection – plus the viral dose – all these things are parameters that are decisive for the spreading of a flu-like disease. And some variations of the RNA code affect the fatality rate. The "core" of the disease is some molecular biology inside cells: viruses become the masters in a much larger cell that they enslave (the cell becomes obliged to produce the virus, much like a PC slave is obliged to constantly spit politically correct lies about non-existent races and sexes) and ultimately kill. But before they get to the cell, there are still many layers involving hydrodynamics, aerodynamics, thermodynamics, and other dynamical scientific disciplines. The "political types" wanted to reduce everything to "static" things – both in the usage of the naive "static" (non-dynamical) laws of physics and their worshiping of the "statist" (big government) organization of the human society.
Of course, scientists in more common-sense scientific establishments – including the Czech epidemiologists – had much more physicist-like approaches: they still seemed to realize that the wrestling with epidemics is a medical i.e. scientific problem, not a political one. Doctors (and not the activists or generic citizens) are the primary ones who should fight the epidemics – and they know lots of things what to do and what not to do while some aspects may be new and one must be careful before doing wrong things. They know that – like the fundamental processes in physics – the key processes driving epidemics are taking place at distance scales that are much shorter than the size of the human body (and vastly shorter than the soccer stadium). But many other people, including physics PhDs who live in the hysterically PC countries, apparenty adopted the "political" view or the approach of the "humanities" where the increasing control of far left lunatics over the society seems to be the key while science is reduced to several utterly childish simplifications where any sort of "dynamics" is already banned ("statics" from ancient Greece is partially allowed). A viral disease is all about the closure of the soccer stadiums, they became to insanely parrot.
Everyone sees that the speedy degeneration of the Western societies is giving much more room and power to the filthy, destructive, and fanatical brain-dead leftists, a purely politically defined group. But the pathological processes also take place at other levels. More generally, people tho think in the physics-like way are being driven to extinction, submission, and silence (or they are downgraded to narrow Fachidiots who only decide about some academic questions with no implications) – while the people whose minds scientifically live in the Stone Age are overgrowing and taking over. This is the opposite direction from the direction that mankind followed when it was making progress in recent thousands of years. In some localized technological environments, positive progress is clearly still taking place but at deeper, more widespread levels of the society – which decide e.g. about the question whether technology XY (nuclear energy or anything else) will be allowed at all – the progress has already switched to the negative sign, away from physics, away from the truly meaningful understanding of how things work and how to use this knowledge. Increasing spinelessness of the physics PhDs may be partially blamed for this deterioration, too.
And that's the memo.