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Comment by bitdiddle | Hacker News Reader

I've always been curious about McCarthy's motivations and whether he was informed by Church's work on the lambda calculus. I heard he was schooled in functional analysis and symbolic differentiation and operator theory were what drove the invention of lisp, AI came later. I'm sure I could research it but I'm too lazy :)

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That sounds like a new version.

McCarthy says in his 1960 paper about Lisp just in the first paragraph of the introduction:

> A programming system called LISP (for LISt Processor) has been developed for the IBM 704 computer by the Artificial Intelligence group at M.I.T. The system was designed to facilitate experiments with a proposed system called the Advice Taker, whereby a machine could be instructed to handle declarative as well as imperative sentences and could exhibit ``common sense'' in carrying out its instructions. The original proposal [1] for the Advice Taker was made in November 1958. The main requirement was a programming system for manipulating expressions representing formalized declarative and imperative sentences so that the Advice Taker system could make deductions.

So it was developed by an AI group for an AI software (Advice Taker).

well sure, McCarthy worked on that when at MIT, right? That AI group was also doing a computer algebra system, so symbolic differentiation was a current problem.

He is credited with the invention of Lisp though, and had a lot to do with Algol. I'm just curious when the connections between lisp and lambda calculus came about. Did it come later with the Scheme work at T at Yale or was it there also in the earlier work on Lisp.

I asked a former colleague about this, Jim Griesmer (who worked on getting the 704 lisp running on the 360 machines), and it was he who mentioned McCarthy's background in analysis.

EDIT: ha!, a little googling reveals[1] this story, not very definitive but interesting nonetheless. I should add that Jim Griesmer also told me that Minsky wrote his thesis on turing tapes or some such thing, because his advisors thought AI wasn't yet a developed field.

[1] http://brainbrain.blogspot.com/2006/06/dinner-with-john-mcca...

McCarthy himself said of his pre-Lisp research:

"To use functions as arguments, one needs a notation for functions, and it seemed natural to use the -notation of Church (1941). I didn't understand the rest of his book, so I wasn't tempted to try to implement his more general mechanism for defining functions. Church used higher order functionals instead of using conditional expressions. Conditional expressions are much more readily implemented on computers." - History of Lisp: http://goo.gl/EDuhl

I've always liked the fact the he did so much with a book he didn't understand the whole of. :-)

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