This morning I received an email from one of my friends from my Master’s course at Cambridge, informing me that Peter Lipton, my Ph.D. supervisor, had died. This was a great shock; he was only in his fifties. There are good general obituaries in the Guardian and on the Cambridge Department of History and Philosophy of Science website, but I want to write a bit about his impact on me, because it was substantial.
I first met Peter (and it was “Peter” from very early on) in November 1992. Six weeks into the final year of my Physics undergraduate degree, I had suddenly come to the realisation that I didn’t want to study physics, and certainly didn’t want to spend my life doing it. I thought about changing to HPS for graduate work, but looking at the past exam papers made me think that I’d really rather be doing that subject now. So, I asked about changing subjects. Fortunately, at Cambridge Physics and HPS are, administratively, the same subject, both being part of the Natural Sciences Tripos, so the change was not impossible. My tutor dispatched me to talk to Trinity’s Director of Studies in HPS, Peter Lipton.
As I remember the meeting, Peter listened, told me that it would be difficult but possible, and then walked down to the corridor with me to the much bigger office of the then-Head of Department, Professor Redhead, to make sure that it would be permissible for me to transfer.
It is entirely characteristic of Peter that, when Professor Redhead retired, he did not move to the bigger office, instead converting it for use by graduate students as a computer room, and as an office for junior members of the Department; I had a desk in there for a few months while working on Starry Messenger.
As both obituaries note, Peter was a brilliant teacher. My late transfer deprived me of the pleasure of attending many of his lectures as an undergraduate, but when I later became a supervisor I had a good excuse to attend the courses my students were taking. His lectures were always clear, amusing, and memorable. Indeed, they were so memorable that the “transcribed Lipton lecture” was a persistent problem among submitted essays. In many years, the students produced a spoof exam paper, and for several years one of the questions was “Produce a transcription of your favourite Peter Lipton lecture. Remember to include stage directions for all visual jokes”. I have never attended any other undergraduate lectures of that quality, and, despite taking them as a model, my own efforts fell far, far short.
However, his teaching was not limited to his lectures. He also founded and ran the Epistemology Reading Group, a seminar that focused on a single text over the course of a term, whether a book or a collection of papers. At those seminars, and at others he chaired, he was skilled at drawing people into the discussion, and at giving people at all levels the opportunity to make the initial presentation. One of my contemporaries remarked that he also had a talent for “clarifying” student questions in a way that made them vastly more intelligent than the initial questioner had managed, all the while giving all the credit to the student. That group appears to have inspired many other similar groups; the HPS seminar page lists over half a dozen groups, with others on hiatus this term. The only group I know it inspired is the Medieval Science and Philosophy Reading Group that I organised, but the other groups all followed it in time while being contiguous in space, and thus a good Humean would conclude that Peter’s example caused them to come into existence.
And then there are his talents as a Ph.D. supervisor. My thesis was immeasurably better as a result of his comments and the discussions we had. Quite a common situation was for us to spend twenty minutes or so discussing a single sentence, leading me inexorably to the conclusion that, perhaps, I needed to devote a little more space to unpacking that idea. He would never start by saying that an idea was poor, but would, instead, raise objections to it, and let you work out for yourself that it was a non-starter.
Of course, if you could overcome the objections, so much the better. A chapter of my dissertation was devoted to his book, Inference to the Best Explanation. More specifically, it was devoted to why it was fundamentally wrong. Despite that, he supported me in my attempts to make the arguments as strong as possible. In 1994, during my M.Phil studies, Peter gave me a copy of the book, with the inscription “To David, Who may come up with a better explanation”. That encapsulates his attitude to his students; the desire to see them do well, rather than to preserve some sort of intellectual superiority.
As well as this attitude, he mastered all the basic skills needed in a good supervisor, but so often lacking. He read all the drafts I gave him, no matter how many, making comments all over. Appointments could be made for a couple of days later, just long enough to give him time to read, and during the meetings he would always give me his full attention. I thought at the time, and still think now, that I could not have had a better supervisor.
As if this were not enough, Peter also gave me my first opportunity to teach, recruiting me to supervise the final year undergraduate course during my MPhil year. This was provoked by an established supervisor getting a job and suddenly vanishing, and it took me a little while to get into the swing of supervising. I know that I tried to model much of my teaching on Peter, and that, in many respects, I fell short.
Both obituaries mention Peter’s sense of humour, which was good and never cruel. Students and colleagues could always laugh at his jokes, because they were never the butt. Characteristic was his response when I sent him the (Japanese) invitation to my wedding: “Thank you for the invitation, which is very pretty if entirely lacking in accessible semantic content”. It is an in-joke, but one that we could share.
The last time I was in Cambridge, with my (then) wife-to-be, we almost literally bumped into him in the HPS Department, and he immediately invited us for coffee. I was very pleased that we’d had the chance then, but I never imagined that it would be the last time I would see him, or the only time that my wife would. Even though my life has moved a long way from Cambridge, I feel a profound sense of loss that he is no longer there, explaining to undergraduates why it is difficult to demonstrate that it is a better idea to leave the third-floor lecture room by the door than the window. He was always part of Cambridge HPS for me, and I had naturally assumed that he always would be.
The Department has established a Peter Lipton Memorial Fund, to support undergraduate, post-graduate, and post-doctoral research. I cannot think of a more fitting way to remember the best teacher and nurturer of new researchers it has been my privilege to know.