Don Knuth: BCS/IET Turing Lecture

Earlier this week was the annual Manchester BCS/IET Turing Lecture, and this year's guest speaker was Don Knuth. Possibly he's best known (at least to me) as the author of the seminal "The Art of Computer Programming" (a multi-volume book which he began in 1962, and continues to work on to this day - subvolume 4A is the most recently published, with another 5 sections still to come), and the typesetting system TeX (pronounced "tek", and used for typesetting countless Ph.D theses - including mine). However Knuth's contributions to computer science throughout his long career (he's now in his seventies) are staggering - as are his "extra-curricular" activities, which include writing novels and playing the pipe organ.

So it was quite an opportunity to be able to listen to this giant of computing first hand - even more so since rather than a straightforward lecture, this was actually a Q&A, with Knuth taking questions from the audience. After opening with a concise explanation of the significance of the number 885205232 (which I won't spoil by revealing here, since it's a puzzle in his book "Selected Papers on Fun & Games", other than noting that it involves Alan Turing's manual for programming the Ferranti Mk. I computer), Knuth fielded questions on various topics including: elegance in programming languages, the public's fear of computers, "busy beaver" numbers, the best way to teach programming to elementary schoolchildren, and whether an aptitude for programming is an art or a "genetic defect".

Throughout his answers were thoughtful, often surprising (for example, making a case for pointers in C as an elegant language feature), consistently interesting, and delivered with characteristic humour (Knuth was once published in MAD magazine, and is famous for the quote "Beware of bugs in the above code; I have only proven it correct, not tried it", amongst others). In response to a question about "what are we 'enabling the information society' to do" (a reference to the BCS's current mission statement), Knuth initially replied "to have jobs", before more seriously reflecting that "there's a long way to go improving what we already have at the moment."

Although Knuth's world of computing feels like it's a long way from the one I inhabit, it was a great privilege to see and hear such a legendary figure - in spite of his age he seems as lively as ever, both physically and intellectually, and still enjoying it - and his career is truly inspiring: when asked what he'd do differently if he had his time again, his reply was that he wouldn't change anything. "In my case," he said, "Murphy's Law hasn't worked - so many things that could have gone wrong didn't."