Here’s Knuth’s original “Art As Programming” lecture as a PDF:
http://www.bluetail.com/~luke/misc/knuth-turingaward.pdf
Any new activity tries to dignify itself by declaring itself “the same as” an older, more respected activity. Art is still trying to make out it’s a liberal art… As the new activity becomes more respected for its own achievements, this becomes less of a necessity.
I’d make the opposite claim to Knuth. It’s not that programming is an art. it’s that art is a form of programming. By this I mean it is a way of structuring a set of symbols to generate a state or set of states in a given system, in this case human consciousness. The state generated may not be the same in all people but then a program may not generate the same states (or even run) on different machines, even if it’s written in java or ANSI C.
Cave paintings are programs for hunts or rituals, and it goes on from there…