Bob Henderson wrote an autobiography for Nautil.Us (via CIP):
What Does Any of This Have To Do with Physics?
Einstein and Feynman ushered me into grad school, reality ushered me out.
He's a Rochester theoretical physics PhD who had come to the grad school after he read some New Agey pop-science books and left a cushy engineering job. He grew disillusioned and at the time of the PhD defense, he decided to switch to Wall Street which he left in 2012, i.e. 15 years later, and became a science writer. While the content of the article is annoying, I think that he is an excellent prospective novelist.
Henderson complains that his dreams were destroyed, he lost the faith that theoretical physics is meaningful or theoretical physicists are marching towards a holy grail. His reasons to leave the university world have nothing whatever to do with my reasons – in some sense, they are the opposite ones – but I am highly familiar with this kind of a frustrated talk because it's widespread among (especially young) physicists. Well, this frustrated talk about physics is less widespread among older physicists because before they reach the higher age, most of the young whiners get eliminated. It's that simple.
Before we look at Henderson's whining a bit more closely, I want to say two more general things. First, it's probably not an accident that the "hero of 2016-2017" in such a popular article is someone who left theoretical physics and mostly began to hate it. Decades ago, such popular journals preferred to celebrate successful theoretical physicists but quitters are apparently more fashionable nowadays. This subtlety strengthens the claims that the science media have switched to a new mission, to hurt theoretical physics.
Second, there are surely lots of other fields in which most people remain relatively unsuccessful and disillusioned. I am sure that there are lots of boys who want to be the world's best athletes and tennis stars and anything of the sort (or actors, add your favorite famous occupation) but find out that not everyone becomes successful and the life of the unsuccessful ones may be hard. Djokovic's life may be comfortable (although I am not certain even about these statements) but for every Djokovic, there are thousands of would-be stars who remain broke and don't get rewarded for their efforts.
Nevertheless, many people play tennis in the afternoon even if they don't earn the same money as Djokovic. Most of those just accept that they're not as good as Djokovic – but tennis is still fun for them, anyway. For some reason, people (including Henderson) don't want to accept that they're less successful than the top theoretical physicists simply because they're not as good. Without the decent salaries and big prizes, these would-be "physicists" find out that they don't actually like physics at all.
Third, Henderson's personality is clearly not that of a theoretical physicist, a fact that the pop-science books have obscured to him. You may see that pop-science books often present physicists as some kind of magicians who are having a great time under shining lights all the time – like Harry Potter or at least the Hollywood stars. What a surprise that many people who actually try to do physics grow disillusioned.
OK, let's start to review his memoir. In 1993, he went to Rochester's graduate school to study theoretical physics. He had read a lot about Einstein and Feynman, they were great guys. But Henderson also mentions The Tao of Physics and Zen and the Art of Motorcycle Maintenance. I know these two titles but haven't read the books.
In spite of that, I feel almost certain that these are not the books that the people whom I consider physicists or prospective physicists are attracted to. Books like that may use the words borrowed from physics but their whole way of thinking is largely unscientific. If you are a physicist who has a friend who believes in mysterious stuff peppered with physics vocabulary (or vice versa), I don't have to explain to you what's the difference between you and your friend, do I?
There may be some similarities – some shared excitement about mental, spiritual, or non-practical questions – but the differences between science and religion/superstition are perhaps greater than the similarities.
It is imaginable that people attracted to New Agey books could do good physics. But in general, I think that it's safe to say that an overwhelming majority of readers of similar books are simply not equipped to do physics. You know, the "opinion" that these superstitious and religious approaches aren't the most sensible way to approach the fundamental laws of physics isn't something that people like me were adopting when they joined a graduate school.
With a debatable 1-week high school exception, I have never had any inclination to look into these superstitious and religious books claiming to be books about physics. Those books reflect a naive, unscientific approach to the truth. They propose easy solutions. Just believe in something, we're all united, God penetrates all of us and is spread to all our bodies, whatever (I am vaguely reproducing some excited lessons I received from a New Age friend LOL), and you get close to the deepest truths about the Universe.
Sorry, you can't. With these mysterious vague superstitious proclamations, you haven't learned a damn thing. The learning of the physical truth about the Universe obviously does require some calculations, often long ones, or a careful argumentation and hours of mental work in which the brain often burns and it is producing nothing useful for the path most of the time.
This is a sketch of the "path towards the deep laws of the Universe" that I already had in mind when I was 4 years old or so – and I think that other physicists who don't relate to Henderson's complaints would tell you something similar. Henderson is telling us that he was gradually discovering some of these things during his grad school years. One actually has to work hard at some moment, be materially modest, be confused much of the time, and try many paths that don't lead to interesting outcomes, while the greatest discovery in a century arrives relatively rarely (approximately once a century, if you want to know).
Those are shocking facts!
You should have known it before you entered the graduate school. Quite generally, I would guess that people who read about "tao" and "zen" are likely to face some problems as grad students of theoretical physics – as far as I can say, those problems may be exactly as severe as the problems of those whose background is all about "Jesus" or "Mohammed". Those are not helpful prerequisites for the discipline. And if the readers are told that those are good prerequisites for the research in theoretical physics, I think that these readers including Henderson have been deceived by the writers of the superstitious books and they may demand a compensation.
Another detail is that Henderson went to University of Rochester, NY to study theoretical physics. It may be an OK school but it is in no way a university that is close to the top in the world's cutting-edge theoretical physics. Henderson's adviser Sarada G. Rajeev may be a local Rochester star in theoretical physics but that doesn't necessarily mean that he's a global star. Click at the hyperlink to see his papers. It's a decent list for a career at such a university but it's not quite the same list as if you look at e.g. Polchinski's record.
I am saying it because if Henderson wanted to search for a theory of everything, going to Rochester doesn't look like a straightforward, sensible path towards that goal. It's plausible that someone at Rochester – or someone with a degree from Rochester – would find a theory of everything. But if that's so, she will have to be repeatedly lucky. The starting point looks more troublesome when you combine all these strange details. If you want to professionally search for a theory of everything, read "tao" and "zen" and go to Rochester. Well, not really. ;-)
A minute ago, I mentioned tennis and the people's ability to understand that they're not as good tennis players as the world's best tennis players. In fact, I am absolutely convinced that the intellectual gap between the best theoretical physics groups in the world and those at Rochester (or worse) is far deeper than the difference between Djokovic and the average Portuguese players, to pick a random non-stellar tennis nation. It's questionable whether places at the level of Rochester (or Portugal) should claim to produce "researchers of a theory of everything" at all. A theory of everything could be too big a game for such places that simply don't belong to the elite. The very statement that they're doing something of the sort is deceptive for most of those non-elite places. These non-elite places should describe their work with a more humble language, otherwise they're deceiving prospective students and sponsors.
A big part of Henderson's story is about the modest material conditions that physics graduate students – and even postdocs etc. – sometimes experience. They're sometimes poor, sometimes they're not. But I do think that the folks who have no problem with such modest conditions – similar to those of monks – are more likely to be "natural theoretical physicists". Readers of "tao" and "zen" books may think that it's cool to search for the deep truths and be as materially undemanding as monks – when it comes to the housing, food, beverages, traveling, sex, whatever – but when the reality arrives, they may find out that they are not really this modest and the usual biological needs do play a big role for them.
Again, I can't relate to Henderson's story because I really don't have a problem with extremely modest material conditions but also solitude and other things. Some people earn bucks by writing about saints and then there are people who just shut up and they are saints. I must humbly admit that I am one of those ;-) while Henderson probably never was. Just to be sure, I am not saying that all theoretical physicists live like monks. You can earn lots of money (think of the Milner $3 million prizes), jobs like the Harvard Junior Fellowship bring some mandatory opulent life, and people who become career professors are materially insured for their life from most viewpoints.
But I want to spend more time with Henderson's disillusion about the research projects. He had to learn lots of papers and he really didn't know how much he has to learn. When you're thrown into research, it is different from a university course. At school, the instructor may have outlined the path for you and you are just following the plan. Many students have probably done "almost the same sequence of steps" before you. Locally, in each lecture, you may deviate a bit, you may calculate various things in different methods, learn something differently than others, but the big picture of the path is clear.
There's nothing of the sort when you're an independent researcher. Tens of thousands of papers (and thousands of books) have been written about theoretical physics. You can't – well, you shouldn't – read all of them. You must pick a subset that is useful for your goals or, to say the least, that is useful for a goal that you may pick as your own even though your expectations could have been different.
You should have a rough plan to get through this hopeless chaos. One aspect of the plan is the realization that most of the papers that have been written are redundant noise (or they are wrong). You want to want to do something more interesting than what the authors of average papers did. The second aspect is that even among the valuable papers, there's a lot of redundancy so you don't need to read everything – it gets repeated – and you may and you should rediscover many of the important things yourself, anyway. And the third aspect is some degree of specialization. You must admit that you won't understand absolutely everything that was written by the other physicists, even if it is correct, and you must live with this fact. Non-scientists live with it happily. As a physicist, you should still understand a vastly greater percentage of the physics wisdom than the non-physicists.
Some self-confidence is therefore highly desirable, much like some humility. On one hand, you must know that you will rely on the work of others, stand on the shoulders of giants from the past and present, use some textbooks or reviews or standard courses, and use the skills and comparative advantages of your collaborators. On the other hand, you must feel that you basically don't need those things. You don't need to read tens of thousands of papers most of the time. You may rediscover everything you need or at least find the right place where you may learn a known thing when you need it. The dominant theme should be that you are refining your own picture of the laws of physics and all the other people from the past and present are just helping you. Most of the time, you are thinking for yourself and you believe that you're smarter than almost everyone else. If this ambitious belief of yours is rubbish, you should get eliminated. But some people may survive and they really are using their brains independently, their intellectual self-confidence is justified (even though they sometimes hide it), and those have really created and are creating the skeleton of physics.
For a grad student or any "junior" member of a collaboration, it's quite normal – and logically justifiable – to do some brute force work whose broader importance isn't understandable to him. Professors are sometimes abusing grad students as slaves or robots. And they love to repeat (true) jokes about it and to count the research work in kilo-graduate-student-hours. But this fact should be obvious to everyone who cares. It is not an exclusive feature of physics and it has a understandable justification, too.
You know, the professor who directs the "big picture" of the research project may be doing the seemingly "easier" part of the job – and he may work for much less than 15 hours a day, a figure that Henderson mentions – but he may still be doing the more important part, just like the boss of an innovative company. His skills to direct the "big picture" of the project are the most scarce resources. Imagine that you live 100 years ago and want to produce cars. To do so, you need some experience e.g. from Henry Ford's company. Well, you are probably going to do some more ordinary, boring work. That has an easy explanation: You're not (a) Henry Ford (yet). Of course you're not the one who is inventing the big strategy and giving the orders to lots of employees. You're not the damn Henry Ford. It is not even clear whether you're good at the things that Henry Ford is reasonably good at. So how could you be Henry Ford?
There's a simple recipe if you're dissatisfied with your place. If you want to do things like Ford and give orders to others, become a Henry Ford yourself, if you can. You must accumulate some capital – money, fame, and credibility, whatever you need – and then you will be able to employ your workers. Or your graduate students. These two examples – and many others – are obviously analogous.
Theoretical physics research may be among the occupations with the smallest role played by plans. One really has a lot of freedom in making his decisions – what he should read and study and calculate and focus on – and indeed, that's why one can get completely lost, too. The shape of the final product (theories of Nature) is almost completely unpredictable, too. But this freedom (which may lead to good or bad outcomes) and the unparalleled depth of the initially unknown wisdom is one of the features that makes theoretical physics so remarkable.
It's hard to give some recommendations that would help everyone escape the potential mess. No universal solutions like that exist. It's unavoidable that they don't exist and it's good that they don't exist. There are many decisions to make, so some people – and probably most people – will unavoidably get lost. What should you do if you don't want to get lost? Be smart, be hard-working, but don't be submissive, be stubborn, be successful, and don't be unsuccessful. These recipes are not too helpful, of course. Some people aren't that smart. They aren't independent enough. They get manipulated. And if they don't get manipulated, they really don't know what to do. Indeed, being an independent researcher – and especially a "principal investigator", if I put it in this way – means to be able to make many such decisions. So the whole idea of recommendations "what you should do" in such an occupation is an oxymoron. If someone else could tell you what to do, nothing would be left for your actual job. The decisions are your job. To ask "what to do" is basically equivalent to asking "do the job for me".
In the college but also in the later years, I was talking to lots of people who begged for recommendations like that. What should I do not to get lost? My answer was never so direct but yes, my current answer would be: If you need this leadership repeatedly, just quit it. If you don't know what you're doing, why you're doing it, and where you are going, and how you may roughly get there, then it's a bad idea to start or continue the journey. People who are picking an occupation should feel some "internal drive" and they should have at least a vague idea what they're doing, why, and how. Again, I don't think that this common sense only holds in theoretical physics. Theoretical physics only differs by the deeper caves in which one may get lost – because deeper caves are being discovered or built by theoretical physicists, too.
Another complaint by Henderson was that his adviser (who was 5 years older) "knew" what the result of their joint project was supposed to be and that's where they ultimately got, indeed. This finding was shocking and disappointing for Henderson, a junior collaborator. I don't understand why it's disappointing. It's common sense. Many projects work like that: One has a hope that there's a certain kind of an answer that can be found and sufficiently rigorously justified. The "senior", usually more experienced (and sometimes, indeed, "more talented") members of the collaborations have some hopefully correct vision about the "big picture" while the other members are expected to do much of the brute force calculations. How could it be otherwise? This story only says that some researchers should have some idea where they're roughly going. And then it's saying that some collaborators – well, the "senior ones" – have a better idea than others. Does one really need to torture himself for years in the graduate school to understand these common-sense tautologies?
In the previous paragraph, I've used some big words. But the actual project that Henderson discussed was his paper with Rajeev, Quantum gravity on a circle and the diffeomorphism invariance of the Schrödinger equation. Well, this paper from 1994 only has 3 citations at this moment. I know the rough content. The tiny number of citations after 22 years indicates that this was probably not a paper that finally found the theory of everything. Or anything else that was revolutionary. Well, it was a much weaker paper than the average paper in the field, too.
Some appraisals by Henderson are therefore correct. This paper couldn't have fulfilled Henderson's dreams about "tao" and "zen". Also, if you have this particular paper in mind, new light is shed on many other claims by Henderson. For example, he said that Rajeev's vision about the final result was finally confirmed, after difficult calculations. Was Rajeev a visionary? Well, a more accurate evaluation could be a bit different: Rajeev simply invented some kind of a paper, including the conclusions, and he employed his grad student Henderson to fill in some details so that the story looks at least somewhat convincing. This is the "Al Gore Rhythm" to write papers in some disciplines that is being used often if not predominantly in soft scientific disciplines such as the climate science. The conclusion is decided in advance and all the seemingly complex, long, and technical language and formulae is only inserted to make the conclusion look more scientific! It's not real hard science, however. If you verify the argumentation really carefully, you usually find out that something important is wrong with the paper even though "local regions" of the paper may look kosher.
But the paper still doesn't look too convincing. You know, there are better physicists than Rajeev and most of them would probably agree that the paper hasn't found any important principle or mechanism in quantum gravity at all. 22 years after the paper appeared, most top theoretical physicists would almost certainly disagree with the conclusions by Rajeev and Henderson, e.g. that there's a canonical link between distance and the phase of a wave function in quantum gravity. It is one of the papers that try to study quantum gravity as if it were a local field theory. But quantum gravity isn't quite a local field theory. In spacetime dimensions lower than four, theories of quantum gravity may look almost indistinguishable from local field theories (and there exists e.g. a formal proof of the equivalence of 3D quantum gravity and 3D Chern-Simons theory) but I think it's right to say that even in the low dimensions, this similarity is deceitful and overlooks some delicate details that become very important in higher dimensions. At any rate, what they found couldn't have been meaningfully applied in the theories of quantum gravity that are really interesting and that we care about, in \(d\geq 4\).
It means that Henderson was 1) a junior member of this collaboration, a status that understandably involves the shortage of independence. But 22 years after the paper was written, we may see that the shortage of independence was more severe than previously thought. Henderson still failed to understand that their "solution" to the problem of the "quantum mechanics on a circle" wasn't necessarily "the" right solution or "the" right approach to this kind of a problem – according to the truly best physicists in the world. While Henderson understands that "quantum gravity on a circle" is a special toy model that isn't likely to teach us much about the big problems of quantum gravity, he still doesn't see that even this toy model was probably solved in a way that is conceptually uninteresting if not strictly wrong. Henderson misunderstands his own paper to the extent of not being able to imagine that something could be problematic about it.
You know, only a small portion of physics PhDs get really close to the world's elite. But I think that after some years, even the other ones should be able to understand and see the difference between the top physicists and those who are not top physicists at all, at least in a fuzzy way. If they can't even see why top physicists are generally more influential than the mediocre ones, it shows that they really don't have the talent for the discipline.
We also learn that Henderson began to hate Rajeev because the latter didn't care about the suffering of the former and dashed his dreams. For a year, Henderson tried to work in isolation. It didn't work too well. He returned, Rajeev accepted him, but soon afterwards, Henderson was hurt when Rajeev asked "Do I have to explain the fiber bundles again?" Come on, is it so terrible to hear this question? Fiber bundles are a hard enough concept – used by people who really want to think like trained mathematicians – but if they're important enough for some project and if Rajeev spends some time by explaining them to someone else, it may be frustrating for Rajeev to see that he has wasted his time by the pedagogic efforts. So why couldn't Rajeev ask "Do I have to explain the fiber bundles again?" Is it a question that one may really get offended by? Have you tried to think about the interaction from Rajeev's perspective, Mr Henderson? Again, I think that this situation is not specifically tied to theoretical physics. If a coach teaches something to a tennis player and it's completely ignored a day later, the coach may also get reasonably upset and emit an irritating remark, can't he?
A theme underlying the story is the tough job market. The number of faculty (and postdoc) jobs is too small relatively to the number of theoretical physics graduate students. I think it's true, the tension has gotten even more extreme in recent years, and the suffering that many young brilliant theoretical physicists I have known had to repeatedly go through was almost heartbreaking. On the other hand, I am pretty sure that the number of faculty jobs shouldn't grow enough to turn e.g. Mr Henderson into a theoretical physics professor. I think that his – nicely written – story makes it clear that he pretty much never had a clue about theoretical physics and he still doesn't have a clue. He isn't thinking as a physicist.
And it's not just about the Virasoro algebra and Yamabe problem, phrases that Henderson used in his and Rajeev's 1994 problem but Henderson "couldn't define them for us today", as he told us. He was clearly misunderstanding and he is still misunderstanding some much more general issues about theoretical physics and what it really means to do research on it (and maybe in science in general). Years after he joined that field, he may still be shocked when he discovers that physicists sometimes have to make independent decisions and similar spectacularly profound wisdoms. ;-)
Again, his prose is impressive – and includes all the linguistically colorful, redundant, and emotional inserted details that make some writers famous and that guarantee that I have never been a reader of novels LOL :-) – but his opinions about physical concepts that are described in his prose are typical opinions held by the laymen, especially when it comes to the frustration caused by some features of physical theories that physicists actually love. A paragraph complains that there are at least three "pictures" to define the time evolution in quantum mechanical theories – the Heisenberg picture, the Feynman approach, and the Schrödinger picture. Henderson was apparently disappointed – and is still disgusted – by the huge number of the pictures (three) – it's not shocking that many crackpots display irrational, anxious reactions to theories with \(10^{500}\) solutions because many people find "three" to be a terrifyingly high integer, too – and he was and he still is repelled by the idea that the deeper theories of particle physics could suffer from the same "problem". He says that the Holy Grail could be a hall of mirrors. It's a great literary metaphor but what's not great is that the hall of mirrors clearly scares him.
Please, give me a break. The transition from the Heisenberg picture to the Schrödinger picture is a simple time-dependent unitary change of the coordinates on the Hilbert space. It's obvious that in every theory that has some time-dependent quantities (and every theory that we use deals with those), one may redefine them by field redefinitions and, when they carry Hilbert space vector indices, those include the unitary transformations of the Hilbert space. Of course this freedom will always exist as long as physics will be based on some quantities (undoubtedly) or on Hilbert spaces (almost certainly as well). Why would one be disappointed by the existence of the two pictures? How could someone possibly think about doing research on quantum gravity if he's frightened by the existence of the Schrödinger and Heisenberg pictures?
In a similar way, one may show the equivalence of these two pictures with the Feynman path integral approach whenever some quantities similar to those in classical physics – like \(x(t), \phi(x,y,z,t)\) – exist in the theory. The proof of the equivalence of the path integral to the operator approaches indeed works (before Feynman, it was already sketched by Dirac) and is rather universally applicable. It's enough to learn it once and you're done. It's a cute piece of the puzzle that has been mastered and that a theoretical physicist happily learns and teaches. Yes, it's one of the mirrors in the hall surrounding the room with the Holy Grail. Why would one be disappointed by those? It makes absolutely no sense.
In fact, these mirrors – rhetorically different but physically equivalent descriptions – became even more widespread, important, and omnipresent in theoretical physics of recent decades when the string and field theory dualities were uncovered. And they're absolutely wonderful, not disappointing. It's surprising that a guy who claims to have been shaped by books about Feynman would think that this multitude of descriptions is disappointing. Feynman always emphasized his hobby to look at problems from many different perspectives. It's so great. Even Apple had the slogan "think different" years before it has turned its consumers to a brain-dead mass of sheep that are using the same boring uninnovative smartphones who suffer from the maximum imaginable group think (not only when it comes to phones but even politics and other things). New perspectives – including new equivalent pictures in quantum mechanics and new descriptions of string or field theory related by dualities – enrich our mind, give us new abilities to solve certain problems or see previously overlooked analogies and isomorphisms. A mirror is an object that a kid physicist likes and is intrigued by. There's just nothing wrong about the idea that a mature physicist who makes important steps towards an important theory has to master a hall of mirrors. Isn't it exactly the kind of an activity that he was trained for as a kid and that he liked? Well, one may see that "tao" and "zen" books are encouraging the readers to do very different and less physical things than to investigate a network of mirrors and how it works.
If Mr Henderson doesn't like the physicist's ability to look at the phenomena through many perspectives or pictures, his thinking is clearly nothing like Feynman's. So maybe Mr Henderson was excited to hear that Feynman was picking locks but he must have understood that picking locks is not the most characteristic kind of work done by theoretical physicists, right? Looking at things with new eyes is what theoretical physicists often need to do – they must be good at it and they're happy and proud about it. If those things (looking at the Universe with new eyes) make you frustrated instead, theoretical physics just clearly isn't the occupation for you.
The final theory may indeed be a "hall of mirrors" in some literary metaphor but if it is so, it's great. A big part of the physicists' task will be to understand how the mirrors work, where they are located, and learn how to use their seemingly complex reflections to learn about phenomena of Nature, including the phenomena that previously looked "trivial" but they were hiding a complex game with mirrors. Again, this is a development that makes a true theoretical physicist happy. A theoretical physicist just wants to see under the surface. He wants to ask "why" even when the practically oriented laymen are "satisfied" and don't ask a damn thing. Many things look simple but this impression is misleading and something rather elaborate may be hiding behind the surface. Theoretical physicists naturally have the desire to remove the surface layer of illusions and see what's inside – and if the interior includes a hall of mirrors, then it's very interesting to know and understand in detail.
I could discuss other aspects of his opinions about physics. One implicit assumption at Rochester – and other schools that don't belong to the global elite – is that you may search for a theory of everything or a theory of quantum gravity while ignoring string theory. This is of course a lie, a lie that certain people maliciously try to spread, and if you combine this ignoring of string theory with the hatred towards the pictures of quantum mechanics, dualities, fiber bundles, and other things, your chances to contribute to the search for a theory of everything really drop close to zero.
At the end, even though this guy is a good writer and I would prefer if people were never emotionally frustrated or disappointed, it's hard for me to feel much sympathy for him. He may have been deceived by pop-science books which made him believe that theoretical physics is something entirely different than what it is. But he continued to lie to himself and to others and he's still searching for problems at the wrong places. Sorry, Mr Henderson, but the end of your love affair with theoretical physics wasn't the fault of theoretical physics.