TIL: From Lisp to Python, but why Peter?

November 15, 2021
lisp ai

Peter Norvig is a well-known educator on A.I. and used to be one of the key figures in the Lisp movement.

His books used to use Lisp in their exercises, but he switched to Python at some point. Today, I came across the Lex Fridman podcast, where he interviewed Peter Norvig and asked him why he made that change.

He gives a surprisingly simple answer at the 43-minute mark.

I was expecting deeper reasons, but his students were having difficulty grasping Lisp, and a questionnaire showed that Python mimicked the pseudocode from the book the most. That's it.

In the short amount of time he had to educate them on A.I., he could not spare the time to educate them on Lisp.

Coincidentally, I also came across this gem at smuglispweeny blog:

At ILC 2002 former Lisp giant now Python advocate Peter Norvig was for some reason allowed to give the keynote address like Martin Luther leading Easter Sunday mass at the Vatican and pitching Protestantism because in his talk Peter bravely repeated his claim that Python is a Lisp.

When he finished Peter took questions and to my surprise called first on the rumpled old guy who had wandered in just before the talk began and eased himself into a chair just across the aisle from me and a few rows up.

This guy had wild white hair and a scraggly white beard and looked hopelessly lost as if he had gotten separated from the tour group and wandered in mostly to rest his feet and just a little to see what we were all up to. My first thought was that he would be terribly disappointed by our bizarre topic and my second thought was that he would be about the right age, Stanford is just down the road, I think he is still at Stanford -- could it be?

"Yes, John?" Peter said.

I won't pretend to remember Lisp inventor John McCarthy's exact words which is odd because there were only about ten but he simply asked if Python could gracefully manipulate Python code as data.

"No, John, it can't," said Peter and nothing more, graciously assenting to the professor's critique, and McCarthy said no more though Peter waited a moment to see if he would and in the silence a thousand words were said.