## Saturday, November 30, 2013

### Was Feynman cognitively lopsided and illiterate?

Stephen Hsu has discussed a long interview with Richard Feynman (AIP).
Feynman's cognitive style (Information Processing blog)
Because I pretty much share all the features that Hsu calls "Feynman's cognitive style" and because I find Hsu's comments fundamentally misguided, skewed, and unflattering, I decided it is important enough to respond.

Hsu starts as follows:
I have always felt that Feynman was cognitively a bit "lopsided" – much stronger mathematically than verbally. This might be partially responsible for his way of learning – it was often easier for him to invent his own solution than to read through someone else's lengthy paper. (Personality factors such as his independent streak, and his strong creativity, also play a role.) But this often left him with gaping holes in knowledge.
Feynman had a habit of rediscovering all the insights and physics that he would rely upon in his research – and thinking about Nature in general. Incredibly enough, Stephen classifies this habit as "lopsidedness", borderline illiteracy, and a vice. Sorry, Steve, but you only represent the group think of average scholars who mostly parrot others and are doing okay with that, scholars whose work is derivative at best and whose confirmations can't really be viewed as independent ones because their writing is always a borderline plagiarism.

Feynman was a charming and articulate speaker who could formulate sentences clearly. He knew how to read, too. But the true reason why he preferred to rediscover things and avoid reading other people's papers is that it is a safer, scientifically cleaner way to collect knowledge. It is a way that not everyone can afford because many other people would simply be incapable of rediscovering all the physics (and Feynman was ultimately unable to rediscover things in physics above a certain level, e.g. string theory, too).

But the scientists who can do it in their actual work like that – and Feynman was an example – should do it.

Hsu is making fun out of Feynman's ignorance of some terminology used by the average researchers, of the fact that he hasn't read some papers by Schwinger and Tomonaga with whom Feynman shared the Nobel prize. But Hsu is completely missing all the reasons why it was the right approach for Feynman.

First of all, science is not the process of learning what other people wrote about Nature. Science is not the process of learning how things are called, either. Science is the process of learning how Nature works. This is no detail; it's been a fundamental insight of Feynman since his childhood (and mine, too); recall the monologue about the name of the bird. You may learn the name of the bird in all the languages (I haven't accurately memorized a single one of them) but you will know nothing whatever about the bird.

Feynman preferred the method of rediscovering everything not because he was lopsided but because he was smarter and especially much more certain about the conditions for science to be solid than pretty much everyone else. Moreover, most of the things people write contain lots of wrong or at least redundant rubbish and it may be either uncomfortable or a waste of time to read too much of that.

Even more importantly, it is critical for a scientist to verify "simpler" examples of statements and insights (theoretical as well as experimental insights) that he or she is going to generalize in his or her work. I don't think this is some subjective feature of a personality or an individual cognitive style. It is really an important quality benchmark for all the science above a certain quality threshold.

To remind you of a context in which Feynman stressed that this "reproduction" or "rediscovery" is extremely important, let me quote from Cargo Cult Science, Feynman's 1974 Caltech commencement speech included in Surely You're Joking, Mr Feynman:
Other kinds of errors are more characteristic of poor science. When I was at Cornell, I often talked to the people in the psychology department. One of the students told me she wanted to do an experiment that went something like this—it had been found by others that under certain circumstances, X, rats did something, A. She was curious as to whether, if she changed the circumstances to Y, they would still do A. So her proposal was to do the experiment under circumstances Y and see if they still did A.

I explained to her that it was necessary first to repeat in her laboratory the experiment of the other person—to do it under condition X to see if she could also get result A, and then change to Y and see if A changed. Then she would know the the real difference was the thing she thought she had under control.

She was very delighted with this new idea, and went to her professor. And his reply was, no, you cannot do that, because the experiment has already been done and you would be wasting time. This was in about 1947 or so, and it seems to have been the general policy then to not try to repeat psychological experiments, but only to change the conditions and see what happened.

Nowadays, there's a certain danger of the same thing happening, even in the famous field of physics. I was shocked to hear of an experiment being done at the big accelerator at the National Accelerator Laboratory, where a person used deuterium.
If you're making fun out of this "reproduction" or "rediscovery", you don't really know what science is, Steve.

Steve's paragraph about Feynman's lopsidedness continues as follows:
In contrast, Schwinger had at age 17 an encyclopedic understanding of what was known about quantum electrodynamics – he had read and mastered all of the literature as a high school kid!
I remember similar discussions about "Feynman vs Schwinger" a decade ago. I have nothing against Schwinger, he was a smart and hard worker, but no doubts about it, I was defending Feynman's approaches. Someone (outside Harvard) suggested that I was obliged to defend Schwinger when I was at Harvard. I think that I have replied that Harvard would have to add a dozen of zeroes to the pennies it was giving me to change my views about these rather fundamental questions about the philosophy of science. I may have been using Schwinger's office but the Linux workstation in my office just happened to be named feynman.harvard.edu.

Most children learn how to read. Whoever can read may read lots of books or papers. It is downright silly to sell this "achievement" as a culmination of the mankind's intellectual efforts, Steve. Schwinger isn't an example but there have been many people who have read pretty much everything that was written in the field they cared about but they were still complete idiots. Marx and Lenin might be listed as damn good examples. They have read a lot – including texts by their ideological opponents – but they were still unable to understand rudimentary issues such as the reasons why communism cannot work. Similar individuals are still hyped by contemporary intellectuals who are as subpar as Marx and Lenin were (if not more so).

Steve is missing the "pragmatic" factor behind Feynman's decision not to read papers doing similar things as he understood:
Feynman: No. No. I don’t think I read the paper. But this must be understood – I don’t mean anything disparaging. If Schwinger hadn’t been in the front yard at Pocono, or next to me, I wouldn’t have known what he did either. I got the same as everybody else. If you can do it yourself, why learn how somebody else does it? So I don’t know precisely what the relation of Tomonaga’s and Schwinger’s work is or the relation of his and mine. I think the relation of Tomonaga’s work to my work is very small. I mean, I think he’s gone around much closer the direction that Schwinger went.
Exactly. When you can derive something yourself, why would you learn another man's method to do the same thing? This is really common sense and this common sense is a principal sensible reason behind the things that Steve is stupidly making fun of.

And science is something different than the history of science. Feynman was in the former business.

In fact, it is not really true that Feynman was a chronic "non-reader" of other people's papers. Many of you may remember that Feynman has stated that there was a period in which he was reading all papers published in Physical Review. There weren't too many, he thought.

Path integral vs creation/annihilation operator

Feynman would be thinking about all derivations in quantum field theory in terms of his path integral approach – something he would develop already in the case of non-relativistic quantum mechanics. The path integral is perfectly fine to calculate the answer to any physical question in any quantum theory that was calculable by any method at that time. Nevertheless, Feynman's preference for the path integral is the reason for some additional stupid laughter by Steve Hsu.

The average instructors prefer to teach quantum mechanics in the operator formalism – and the mediocre and subpar ones prefer not only the operator approach but the operator approach in the Schrödinger picture. However, the Heisenberg picture is arguably more physically justified even if one uses some operator approach. And Feynman's path-integral approach is at least equally justifiable and equivalent.

In fact, for technical reasons, Feynman's approach is superior for all modern theories – theories with some gauge symmetries. The path integral makes the treatment of gauge symmetries natural, unified, automatic, and compatible with the Lorentz symmetry. All the calculations that depend on gauge symmetries may also be translated to the operator approach but the required calculations are much more messy. This messiness is unnecessary.

The very interview shows that Feynman was able to read a paper using the operator approach and find a mistake in it, too. So it wasn't an example of any "gap in physics knowledge". The main justification for Steve's laughter are the creation and annihilation operators, however:
When someone explained the action of a creation operator on the vacuum, Feynman reportedly objected "How can you create an electron? It disagrees with conservation of charge!" :-)
Feynman was obviously thinking about the real-world process of creating a single electron or annihilating one; his thinking was "process-based", in this sense. And he's completely right: you can't do nothing else than to create a single electron (or annihilate a single electron) because it would violate the charge conservation law. And indeed, Nature never does it. The terms in the Lagrangian always do several things at the same moment (create an electron-positron pair while destroying a virtual photon, for example) which is needed for the charge conservation law to be upheld. These terms in the Lagrangian may be understood as (sums of) products of creation and annihilation operators but this decomposition of the interaction terms to individual "atoms" proceeds along a seemingly very different philosophy in the path-integral approach.

The formalism using creation and annihilation operators seems universally important, elegant, and unavoidable to most of us – to some extent, even to me – because we were educated in this way. But as far as physics predictions go, there's nothing "essential" about it that one couldn't do otherwise (with the path-integral tools, for example).

The harmonic oscillator has some energy eigenstates, some spectrum that happens to be equally spaced. You may treat the harmonic oscillator problem on par with all other generic potentials that don't admit a simple solution in terms of creation and annihilation operators. You may still be aware of the special features of the harmonic potential. And in the application of the harmonic oscillators to quantum field theory, you may avoid all these concepts by calculating the scattering amplitudes via the path-integral approach directly.

Feynman was really using this approach to calculate and to think about all the physics problems and the only reason why someone may make fun of it is stupidity combined with lots of group think. If one can do all the quantum physics calculations using path integrals, there is really no point of learning another man's toolkit that doesn't achieve anything that you can't do comparably effectively and naturally.

If you have mastered the path-integral approach but not the operator approach to quantum mechanics, it is legitimate to consider the learning of the operator approach to be as unnecessary if not stupid as learning another human language.

I personally find it natural to think in terms of creation and annihilation operators in many contexts – much of physics may be approximated by "some kind of a harmonic oscillator" with some extra cherries on a pie and the creation/annihilation operators are among the most natural mathematical tools that "solve" this omnipresent physical problem – but I am not blinded enough to overlook the fact that physics may work without mentioning any of these operators, too.

Just like Feynman was used to avoiding creation and annihilation operators, many people remain pretty much ignorant of the path-integral perspective on most quantum phenomena and calculations in quantum physics. The only reason why they tend to think or say that this is less funny than Feynman's avoidance of the creation and annihilation operators is group think. There are just many people who were trained to use the same "language" for the calculation of the scattering amplitudes. But their being numerous is no rational or scientific argument in favor of the superiority of their "language" just like 1+ billion of speakers doesn't make Chinese a superior language or a must (and sorry, U.S. readers, similar comments hold for English as well – I guess that for Steve Hsu, these remarks may be triply inconvenient: one because Chinese is not fundamental, second one because English is not, either, and the third one because languages are not the focus of knowledge).

So I view Steve's criticism of Feynman's "cognitive style" – which actually contains many principles of the scientific method that Feynman considered essential and indisputable – to be a lopsided, libelous, superficial, and rationally unjustifiable testimony of the mediocrity of the present era.

And that's the memo.

P.S.: Steve Hsu wrote another blog post, Feynman and the secret of magic, as a reaction to the blog entry above. I wrote a comment over there, too.

1. Even though I agree with most of your points here about Feynman, I don't think Hsu was really mocking Feynman. I think he was just examining an aspect of Feynman's rather unusual genius. Of course it's silly to call Feynman illiterate, though.

2. OK, Steve used neither the word "illiterate" in this form - nor the word "genius". I think that in the latter case, it's no coincidence because Steve *really* thinks that Feynman was less intelligent.

3. Totally agree! I even thought all this was obvious fact.. A real scientist has to go the whole process himself to fully absorb his discovery, that's how he gets his excitement. If everything had to be learned from books only... what would that say about human nature, and life?.. One doesn't have to be an erudite to fully appreciate science.
Some genius chemist can be the best methamphetamine cook in Albuquerque and still has no clue how to sell it :-)

4. so true... the finger pointing the moon....

5. I wish I had a 'Like button' to press for this post!

6. The ArXiv moderators, in their comment to http://arxiv.org/abs/0712.3934 by G. Forst, reported a case of scientific misconduct pertaining the outcome of the GP-B mission by Ignazio Ciufolini, author of the competing LAGEOS tests. They write: ''This submission has been removed because 'G.Forst' is a pseudonym of Ignazio Ciufolini, who repeatedly submits inappropriate articles under pseudonyms. This is in explicit violation of arXiv policies.''

7. Interesting article Lubos. But I think you should mention that this was true for research (which you may have thought obvious). I am sure that I have read somewhere that Feynman took all physics courses in MIT.

8. Feynman was capable of rediscovering string theory for himself, he just didn't think it was very interesting. He softened his opinion by noting that the intuition of old physicists was often wrong.

Feynman's way of reading a paper was to try to arrive at the result by himself, looking a little at the paper only when really, really stuck.

9. Lubos, since you share aspects of Feynman's cognitive style perhaps you can cast some light on what attributes of yours (e.g. spatial ability?) make that possible. I think it's fair to say that very few people are capable of thinking like that.

10. Excellent post! The only thing I worry about is that one loses too much of their short lifespan rediscovering things. I think sometimes it might be better to just learn the theory and move on. After all, can you imagine rediscovering Newtonian mechanics without any knowledge of it at all? Wouldn't that mean that you're as great as Newton? Feynman was great, but no Newton, and his whole life would have gone to waste if he had tried to discover Newtonian gravity all on his own.

Fortunately, Feynman was very quick at his rediscoveries, and the things he was rediscovering were trivial compared to the discoveries of Newton and Einstein, insights he would have never reached on his own.

11. Dear Richard, I don't really think that the detailed microscopic processes that were going on in Feynman's brain are close to mine - or anyone else's. If there's a similarity here, it's mostly coincidental.

12. What sets Feynman above many others was that he was not just a math whiz. He was extraordinarily curious and much more rounded in his interests than most. He was an effective speaker and had considerable wit and charm.
I suppose that he was and still is diminished by those who may lack some of those broad talents. If the someone who had criticism were a bongo drummer or writer or artist pointing out that he did not understand much of their fields of endeavor it would be more appropriate. But as to physics and for that matter communicating the concepts in a manner that was clear to a broader audience he achieved more than any others of his day, IMHO ,

13. Dear Lubos, Thank you for your detailed response. I strongly agree with your statement: "tolerating and even celebrating differences in the procedures that different people do to solve the same problems." My question was asked in the spirit of adding trying to understand to "tolerating and even celebrating."

I am particularly interested in this because my own thought processes tend towards those you describe. Although I agree that everyone's brain is different in detail at some level, I think there are both similarities and differences at higher levels of abstraction which are worth exploring to help better understand how people think.

This is the spirit in which I engaged in the discussion on Steve's blog (I have the utmost respect for Feynman, his abilities, and his achievements). I suspect Steve's motives were similar ((though what I think is not really relevant, he has spoken for himself in a later post).

14. It is said of Schwinger that he was the one who set himself apart and had a reputation for aloofness. Used his own "wholly idiosyncratic system of symbols that avoided all use of the Feynman diagrams ..." That it was he was isolated and would independently duplicate others ideas and had a " ... Bold, imperious style at makes almost no reference to the work of other physicists ..." . This not surprisingly offended some.
I take these from "The Second Creation " 2nd edition 1996. I think they were both great minds but sometimes the package is important, too.

15. Where can I get The Stephen Hsu Lectures on Physics?

16. I want to add almost anything said about Feynman above is valid also for Landau. He would read introduction of papers and would derive results on his own. He also wrote most of his course of theoretical physics in his head in prison, so he reproduced almost all of known physics. I think what seperates Landau and Feynman from others is that they could feel physics behind the mathematics and they could sort of think without mathematics. This can be the X Schwinger couldn't do but I don't know his work well so I can't really comment on this. Also there was substantial pressure on soviet physicists to do practical things, if Landau was born for example in USA he could do much more on fundamental physics.

17. ISTR that Fermi liked to read papers by first reading the abstract, then setting the paper aside and deriving the results for himself. I suspect it was something of an exercise for him.

Along the same lines, the Moore method of teaching mathematics in it's strict form forbid reading texts and papers. The students were expected to work from definitions and axioms given out at the beginning and then develop the mathematics for themselves.

18. Yeah! 'Balance' is way overrated. :)

So let's here it for the cognitively lopsided. Three cheers! But especially so when it comes to being right more often than wrong.

"Tyger, Tyger, burning bright,
In the forests of the night:
What immortal hand or eye,
Dare frame thy fearful asymmetry?
"
[W. Blake's view, but as he should have seen the beast — from the right side. :) ]

19. Dear John, You write nice comments about Landau, but unfortunately most of those (often repeated) memes are not quite correct. It is often said that Landau totally stopped reading physics papers in the second half of his career, but his closest pupils revealed that he has keys from the Institute library, and he used to spend hours there at night (he has an apartment in the Institute where he worked). He maintained an image of someone who does not read papers, but coming back from theaters (where he went very often) he usually went to the library, he liked reading/working there at night when nobody was around. He worked on his course of Theoretical Physics throughout all his working life, and the year he spent in prison was the only one when he did nothing, he actually was close to death at the time of his release. His attitude towards math was pragmatic, it was a language which you must master before doing research in theoretical physics, he was not keen on rigor but demanded a true fluency in all the relevant and potent branches of math. He has a famous Theoretical Minimum Exam, the sequence of tests in all subjects of theoretical physics; needless to say, the first test was exclusively on math.

Also, I don't think that the pressure on doing practical things was that high, at least in the case of Landau. For instance, I've read many times that Pomeranchuk (one of his best students) kept blaming Landau that instead of focusing on the truly fundamental research of the day, specifically on nuclear and elementary particle physics, Landau was wasting time on little problems in hydrodynamics etc. Landau just laughed back and said that he needs some fun. Well, many things which Pomenranchuk was doing are now totally irrelevant and forgotten (he was a bit of phenomenologist in modern terminology), while little problems even from old fashion subjects which were solved by Landau will probably remain relevant...

20. There are polymaths like Leibniz, Thomas Young, Murray Gell Man, Oppenheimer...who were interested in math, physics, but also in general culture, literature, music, anthropology, languages etc.; and there are those who can focus their genius on one aspect and get remarkable results---like Newton, Dirac, Gauss,
Euler etc.

Feynman had perfect math scores out of high school and mediocre scores in general culture exams. This was in no way indicative of incompetence in them---he was simply not interested in social constructs. When Newton was asked how he was able to solve difficult problems, he said by focusing on them continually.

When Oppenheimer was going on to Dirac about reading poetry in Sanskrit, Dirac asked him why he was wasting his time...it is a different mindset.
The truly original re-invent what they are working on, and, as a result often produce novel and productive

work that is able to generalize the old or even suggest new fields of study.

Curiosity is the key. I find that most of the humans I meet are curiously lacking this attribute, or, if they are curious, it only applies to social constructs.
There is nothing wrong with being a polymath, and there is nothing wrong with having a laser-like focus.
Hsu is just showing his own bias and misunderstanding, I believe. Feynman had a very low bullshit threshold. His story about knowing the name of a bird and not about its habits, characteristics, structure etc is typical of him. A name is vacuous unless it also creates a nimbus of associations about the named object.

21. NASA needed large caliber stooge for the Challenger disaster. Sally Ride was cheap and easy, and fat with publicity, but she bore no technical weight upon the issue. Nobel Laureate Feynman was dying of cancer. How much damage amidst credentialed gain could he do with one last (diminished) hurrah?

22. Not sure it helps understand Feynmann, but by all accounts he was a first rate rhythm player and not just a prof who played the bongos. Possibly his sense of music was perhaps an indication of his deeper insights.

23. Feynman himself said he was limited in subjects like literature- functionally dyslectic. In fact he used exams and papers from a file in his fraternity- like Lubos?

24. Of course I agree with your statements here.

As I have said before, I attended a summer school in Erice in 1964 where Feynman gave a set of lectures when I was still a graduate student. At that time, with the arrogance of youth, I was not impressed. I did not think he was lopsided in any way, but he was deriving for us the eightfold way in his own way :), and I felt it a waste of time to go through it again from another projection. What mostly I remember from the sidelines of the school was Zichichi dancing cheek to cheek with Feynman's wife :).

Then I had the luck to participate at a workshop in 1980 or so, where he was a participant and speaker, and also got to know him a bit personally being his guide to the sights of Athens. On a personal level he seemed well rounded enough, normal, and I got some anecdotes while he was talking to students in the long bus ride of an excursion, which I have shared here I think. He was a flirt with the young students, joking etc, which is well rounded enough imo.

In his story telling I got the strong impression that he had eidetic memory, because he said he could read off formulae from material he only read once, bringing the relevant page to mind. This might be why he did not delve into other people's writings: he knew he could find them if he wanted them in his memory storage.

In his lectures he derived QCD, the forefront research , in his own way. I was mature enough then to appreciate his out of the box thinking.

I would categorize him as having kept the inner child up front, rather than lopsided in any way, and of course that would explain his enormous creativity. (After all we are told that if we are not like a small child we will not be admitted to heaven :) .).

25. Awesome Anna! You are lucky to have been able to approach Mr Feynman ;-)
The way I picture this eidetic memory thing is like holding the end bit of a thread you only have to pull to get all the solutions... You don't even need to follow the long path of the thread because the thread *is* the path.

26. It's seplled dsylecxi. I mean dylsexic. No...

27. A terrific post, my candidate for TRF Comment of the Year. (Runner-up, any one of several posts by lucretius.)

Let me just add my two cents from the peanut gallery. I understand all the arguments in favor of working things out for oneself versus learning by reading textbooks and papers.

However, to someone like me this is like a couch potato watching two Olympic gold medal winners argue over whose training approach is best.

Learning math and physics from textbooks is anything but easy. Textbooks are riddled with mistakes, inconsistencies, and omissions. So picking knowledge up from a textbook is nothing like dipping an absorbent sponge in water. Instead, only a minority are capable of figuring out how to fill the gaps in exposition and quietly correct the mistakes in their own mind without breaking stride. This is a form of creativity.

I hope the rest of us are not forgotten in this discussion: those who need better textbooks and better teaching methods.

28. My feeling is that Feynman was hunted by the fact that he
didn’t discover a physical theory from scratch like Einstein did for example. He is not the “father” of a theory. I think this bitterness is also the underlying reason for attacking String theory.

I will be direct; I think he had an ego in the size of Texas This is not bad per se especially for a physicist but it has shortcomings.