Joe Polchinski’s autobiographical Memories of a Theoretical Physicist has just been published, in an open-access version that is freely available. Much of the volume is what appeared here on the arXiv back in 2017, but this has been supplemented with other material, including an introduction by Andy Strominger and detailed bibliographical notes by Polchinski’s student Ahmed Almieri. If you’re interested in the details of Polchinski’s work, I’d recommend also reading Witten’s biographical memoir here, which covers the same scientific material, but from Witten’s perspective.
Polchinski and Witten agree that one of his three major accomplishments was the anthropic string theory landscape, but I’d argue that this was the opposite of an accomplishment. Instead it should be seen as a disastrously bad scientific argument, one that became a wrecking ball that brought to an end most work towards a better, more unified theory of fundamental physics. Polchinski and Susskind were the two most influential figures in pushing for this argument in the theoretical physics community (Susskind wrote a popular book).
Everyone I’ve talked to who knew Polchinski has nothing but positive things to say about him as a scientist and as a person. I never got to meet him in person, but wish that I had, this might have improved our bad relations. Back in 2004, I wrote an early blog entry that seems to have greatly upset him, by describing (accurately I still think) a popular article on the landscape he wrote with Raphael Bousso for a Scientific American issue about Einstein and his legacy as pseudo-science that would have made Einstein gag. I was not the only one with this reaction to his work, his KITP colleague David Gross also had strong things to say on the topic. In the memoir Polchinski refers to the years of these arguments (and of the appearance of my book and Lee Smolin’s) as ones he found emotionally very difficult. At the time he somehow managed to get the arXiv to ban trackbacks to my blog, for that sorry story see here.
Towards the end of his life the landscape pseudo-science he had so vigorously promoted became a dominant point of view among influential theorists, with even Witten coming to accept it. Polchinski remained upset by my continuing complaints about the subject. One of his last papers, (this one, also see here), extensively attacked me personally, claimed that string theory was true with Bayesian probability greater than 97.5 percent and appears to have been partly a reaction to this blog post. In the blog post I made fun of his claims to have calculated the Bayesian probability of a multiverse as at least 94%. I was unaware at the time that he was already sick with the disease that would later take his life.
Much of this autobiographical memoir is rather technical and will be mostly of interest to experts and specialized historians. The complicated story of Polchinski’s career is very much the story of what happened during this time to the field of fundamental theory in physics. This is a very different story than the usual one of a scientific field’s progress towards greater enlightenment.
Update: A correspondent pointed me to something I hadn’t noticed. In section 3.3 Polchinski writes:
This was typical of Mandelstam, how far ahead he was in much of his thinking. Another example, the first paper that one studies in the
Langlands program today, is the first paper that Mandelstam gave me to read forty years ago.
I wouldn’t describe it the way Polchinski does, but I’m guessing the paper he’s referring to is Montonen-Olive.