dissed by the best

What's a time in your career when you were criticized extremely harshly by someone you respect? Did it help you or set your career back?...

When I were a lad we used to have to walk to grad school, barefoot through the snow, up-hill both ways.

Not. I actually lived 1.5 blocks from my office, in sunny Pasadena So Cal and had a leisurely stroll through the immaculately groomed Caltech campus.
But...

...bear with me.
How I got there has some relevance to the story.

I did my undergrad in the UK, double honours in Mathemtical Physics ("Q" in the old UCCA classification). I came out of that knowing that I was not a mathematician, and that I was happy not to be a mathematician, but also knowing a lot of mathematics. I knew I wanted to go on to post-graduate study in theoretical physics, but I felt very strongly that I needed to learn a lot more before doing research.

In particular I was not at all sure what sub-field I wanted to work in, and this was a problem in the UK, where most PhD programs admitted you straight into a funded line of research with the thesis title already determined. I had an option to stay at my undergrad institute and do a funded MSc, or I could go to Cambridge for the Part III of the Tripos; but, I had for various obscure reasons decided to go to the US, where they expected people to take classes and you had more freedom and more time to decide on sub-field in general.
That much I knew.

What I did not know was that I was almost too late to apply, the process started around christmas, not easter, and there was this exam called the GRE, which was the stupidest exam ever (I took it cold, after flying to New Jersey and staying with my then girlfriend at Princeton, interesting way of doing it, but I did well).
This was before the Net, and information was very hard to come by. I asked the university's career centre, and they basically told me "no idea, but if you find anything out, can you leave the info with us...".
I asked three faculty I respected to give me their top 10-20 choices for universities to "do physics", and then took the union of the list and cut.
I took one "safety school" - which I never completed applying to, because I had offers before their deadline. I skipped the UC's completely because of a sentence in their info about not giving funding ot non-California residents...
I threw Harvard's application form in the bin when I got to the "itemize you family's jewelry holdings".
I ended up getting about half-dozen applications out, got one rejection (the one where I made the mistake of writing an actual "essay" about my research interests, the rejection was a "we don't do that stuff" - I took it personally at the time, but they were right, they didn't do that stuff, and neither in the end did I... - I know now, having been on the other side of the process), but I had several good offers with funding ranging from minimally tolerable to "holy shit! they pay how much?" (I was coming from the UK, remember...).

Now, my de facto advisor, I think, wanted me to go to UIUC and work with Tony Leggett, which would have been very interesting. But, while I had done very well on Solid State physics, the lecturer had been very poor - bad enough to permanently put me off that field.
Had I been a little bit more savy, or had a bit more time, I would probably have been able to narrow my alleged interest to something like "quantum cosmology" and had I had time to look over who was doing what, I would probably have gone to Harvard or Stanford, but I didn't apply to either - don't know why Stanford didn't make my list of places to apply to.

So, for reasons completely unrelated to any rational decision process, I decided to go to Caltech.
Interesting place that.

I was in physics, in a class of 28 as I recall.
I arrived just after String Theory really took off. Everyone wanted to do String Theory.
I was skeptical, I was broadly interested in particle physics, but the Standard Model seemed a bit stale already, and the promise of Supersymmetry was fading.

Superstrings was really hot. And the peer pressure was immense, during orientation we were given the sales pitches and it kept up; eventually a friend of mine prevailed and I took a long hard look at String Theory and decided there might be something interesting there.

In the meantime I was taking classes. I treated the program like a 2 year MSc followed by a 3 year PhD (this was politically a very bad idea, I was supposed to dive into research earlier, but I was naive, and I liked to soak in classes). At the start of the second year, I took General Relativity and Cosmology (Phinney, Blandford and Preskill - astonishingly good class); String Theory (Schwarz); a math class, can't remember if it was advanced functional analysis (think that was spring) or topology or something, I took a graduate math class every term until I was in the thesis writing phase, good for me; Gell-Mann's seminar (which I re-audited two years later when Seth Lloyd pretty much ran it); and Particle Physics taught by Richard Feynman.

Feynman had just got back from leave, having been on the Challenger Commission, and he was "back doing research", I was hanging out on the 5th floor a lot and attended all the talks and seminars, and he gave an interesting talk on 2-D conformal field theory, with clear implications for string theory.
My memory of Feynman's class is that it was mostly anecdotal, he was out to impress, but looking over my notes there was actually a lot of meat there, the discussion of generalization of quantum field theories to N-dimensions in particular strike me, though I have to admit I never got fired up by the discussion of scattering theory, partons and QCD.
I shamelessly cribbed Feynman's illustrations and class techniques for 2nd year Quantum which I was TA'ing at the time.
Anyway, he asked us to write a short paper on a topic of our choice for the end of class.
It was, I believe the last paper I wrote by hand, the next term I converted to TeX to write a paper for Blandford's class (on black hole evaporation and violations of conservation laws during scattering of quantum states - that was an interesting paper, should have followed through on it, might have lead somewhere, but I was a bit naive...).

I chose, cheerfully, to write a straightforward discussion of string quantization. We could write on anything, right? It was for my benefit, there were things I wanted to get straight in my head, and it was clearly relevant to the class. It was not a good paper, not an original thought in it, and not comprehensive enough to be a real review.
I got it back with a single sentence in red across the front - the most brutal savaging imaginable - I got the dreaded "you don't understand shit" (I'm paraphrasing. he was more eloquent).
Ouch.
Then he gave me a "B".

On the way out the TA - Brian Warr (very nice guy who was about to graduate) grabbed me and literally took me aside into another room. He told me three things:
- I was to ignore the comment, it was not true
- what the fuck was I thinking, Feynman did not approve of string theory, serious departmental political faux pas (did I mention I was a bit naive?)
- Feynman's cancer had returned, it was terminal, painful, confidential and made him very grumpy. So he took it out on me...

Ouch. Ouch. Ouch.

Not a good christmas. The next term I approached burnout, like seriously think about going back to working in a fish processing factory burnout, but about halfway through a lot of things got better and I asymptotically started approaching the mythical state of the Happy Techer (as defined by David Brin this is a graduate student in a stable relationship whose research is going well).
And Richard Feynman died. We missed him.

So, did this help me or set me back?
Well, it came very close to setting me back - it was a fairly gratuitous ego blow, and not, shall we say, constructive. Probably part of me feeling burned out the next spring was residual lack of confidence.
In the long run, it arguably helped me...

Maybe 1/4-1/3 of the students in my class worked on string theory, or string related particle physics. Just in time to catch the cancellation of the Superconducting Super Collider and the associated crunch in the particle theory job market, combined with the first lulll in String Theory as university departments decided they had hired enough and no breakthrough appeared imminent.
I think all the students who completed String Theory PhDs got postdocs, but as far as I know only one persisted through it to a tenured position. A lot of very good physicists were forced out of the field - most are now in computing or finance, as far as I've been able to keep track. If I parse some pseudonymous commenter IDs correctly some keep up with the field at Cosmic Variance or the Reference Frame nowadays.

I signed up to work with John Schwarz. One of my flatmates was working on K-theory (anyone remember that!) (he quit before finishing). I was due to work on orbifold compactification of heterotic strings. As I recall we knew, or had a very good idea, of the large number of distinct compactifications, and the idea was that I should classify them and look for solutions that reduced to the standard model or a known superset of the standard model. Or, as I like to think of it, look for physical solutions.
There was a problem - the focus then was very much on calculation, too much so,.I used to argue, quite fiercely, that we should be exploring physical constraints, not mathematical solutions, but that was Not The Way. A lot of the essential concepts of the second wave of string theory excitement had been floated over beer or tequila at the Athenaeum on friday nights, but there was no encouragement to take a serious look at these, quite the contrary.
I visited the UK that summer and gave the worst ever string theory lunch seminar, something on stringy solutions to the cosmological constant problem. I just did not care, the mathematical argument was there (made by one of the Harvard crowd) but it just didn't work and my dislike must have shown quite clearly.
After the seminar, John Barrow took me aside and asked why I was working on this, we chatted for a bit (next time I saw him at dinner at Cambridge he had mercifully forgotten this episode) and two hours after I arrived back at Caltech I was working in TAPIR on relativistic astrophysics.
Data, observational constraints, actual testing of theories, and best of all - to do this properly one really had to be cognisant of most all of physics. I had found my niche.

So, it worked out ok.
I suspect that Feynman's comments started the pre-existing seeds of doubt growing, so even as I started working on Strings I was deciding subconsciously to get out.
Had I done a string PhD I would probably have made it to postdoc, but probably not tenure-track, I know the people who didn't make it and I don't think I would have had the luck or persistence to ride out the hard years of the early '90s.
I still like Strings, and spend some effort on keeping up on occasion. John Schwarz buys me the occasional beer when I bump into him.
I am also an associate member of the Institute for Gravitational Physics and Geometry where Quantum Loop Gravity bubbles as a possible alternative to String Theory.
I needs to know!!!, since it is entirely possible that tests of either theory may come from astrophysics, and it is good to keep an eye out on the possibilities.

I should blog on my real opinion on String Theory sometime soon... sounds like it is time to take sides in the String Wars, eh?
Maybe after I finally finish Lee's book and get the review out.