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Walter Pitts

Walter Pitts (1923? - late 1960s) was a logician who worked in the field of cognitive psychology.

Pitts taught himself logic and mathematics and was able to read a number of languagues including Greek and Latin. At the age of 12 he spend three days in a library reading Principia Mathematica and sent a letter to Bertrand Russell pointing out what he considered serious problems with the first half of the first volume. Russell was appreciative and invited him to study in England; although this offer was apparently not taken up, Pitts decided to become a logician.

He attended lectures at the University of Chicago, without registering as a student, and met Jerome Lettvin with whom he became good friends. In 1938 he met Rudolf Carnap by walking into his office and presenting him with an annotated version of Carnap's recent book on logic. Since Pitts did not introduce himself, Carnap spent months searching for him, and when he found him he obtained for him a menial job at the university. Pitts at the time was homeless and without income.

Later Warren McCulloch arrived at the university, and in early 1942 invited Pitts, who was still homeless, together with Lettvin to live with his family. In the evenings McCulloch and Pitts collaborated. Pitts was familiar with the work of Gottfried Leibniz on computing and they considered the question of whether the nervous system could be considered a kind of universal computing device as described by Leibniz. This led to their seminal neural networks paper A Logical Calculus of Ideas Immanent in Nervous Activity.

In 1943 Lettvin introduced Pitts to Norbert Wiener at MIT, who recently lost his "right-hand man". Their first meeting, where they discussed Wiener's proof of the ergodic theorem, went so well that Pitts moved to Boston to work with Wiener. In 1944 Pitts was hired by Kellex Corporation, part of the Atomic Energy Project.

In 1951 Wiener convinced Jerry Wiesner to hire some physiologists of the nervous system. A group was established with Pitts, Lettvin, McCulloch and Pat Wall. Pitts wrote a large thesis on the properties of neural nets connected in three dimensions. Lettvin described him as "in no uncertain sense the genius of the group...when you asked him a question, you would get back a whole textbook". Pitts was also described as an eccentric, refusing to allow his name to be made publicly available. He refused all offers of advanced degrees or official positions at MIT as he would have to sign his name.

Wiener suddenly turned against McCulloch, on account of his wife who hated him, and broke of relations with anyone connected to him including Pitts. This sent Pitts into a decline from which he never recovered. He burnt the manuscript on three dimensional networks and took little further interest in work. The only exception was a collaboration with Robert Gesteland which produced a paper on olfaction. Pitts died in the late 1960s.