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Meet Walter Pitts, the Homeless Genius Who Revolutionized Artificial Intelligence

Stashed in: History of Tech!, Turing, Homeless, History of Tech, University of Chicago, Artificial Intelligence

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The early history of computing is filled with tragic figures, researchers who truly suffered for their art. Even though I'm an alumna of the University of Chicago, I had never heard of Walter Pitts and his early attempts to model human thought.

I had not heard of him before, either. 

The following June, 1945, von Neumann penned what would become a historic document entitled “First Draft of a Report on the EDVAC,” the first published description of a stored-program binary computing machine—the modern computer. The EDVAC’s predecessor, the ENIAC, which took up 1,800 square feet of space in Philadelphia, was more like a giant electronic calculator than a computer. It was possible to reprogram the thing, but it took several operators several weeks to reroute all the wires and switches to do it. Von Neumann realized that it might not be necessary to rewire the machine every time you wanted it to perform a new function. If you could take each configuration of the switches and wires, abstract them, and encode them symbolically as pure information, you could feed them into the computer the same way you’d feed it data, only now the data would include the very programs that manipulate the data. Without having to rewire a thing, you’d have a universal Turing machine.

To accomplish this, von Neumann suggested modeling the computer after Pitts and McCulloch’s neural networks. In place of neurons, he suggested vacuum tubes, which would serve as logic gates, and by stringing them together exactly as Pitts and McCulloch had discovered, you could carry out any computation. To store the programs as data, the computer would need something new: a memory. That’s where Pitts’ loops came into play. “An element which stimulates itself will hold a stimulus indefinitely,” von Neumann wrote in his report, echoing Pitts and employing his modulo mathematics. He detailed every aspect of this new computational architecture. In the entire report, he cited only a single paper: “A Logical Calculus” by McCulloch and Pitts.

By 1946, Pitts was living on Beacon Street in Boston with Oliver Selfridge, an MIT student who would become “the father of machine perception”; Hyman Minsky, the future economist; and Lettvin. He was teaching mathematical logic at MIT and working with Wiener on the statistical mechanics of the brain. The following year, at the Second Cybernetic Conference, Pitts announced that he was writing his doctoral dissertation on probabilistic three-dimensional neural networks. The scientists in the room were floored. “Ambitious” was hardly the word to describe the mathematical skill that it would take to pull off such a feat. And yet, everyone who knew Pitts was sure that he could do it. They would be waiting with bated breath.

In a letter to the philosopher Rudolf Carnap, McCulloch catalogued Pitts’ achievements. “He is the most omniverous of scientists and scholars. He has become an excellent dye chemist, a good mammalogist, he knows the sedges, mushrooms and the birds of New England. He knows neuroanatomy and neurophysiology from their original sources in Greek, Latin, Italian, Spanish, Portuguese, and German for he learns any language he needs as soon as he needs it. Things like electrical circuit theory and the practical soldering in of power, lighting, and radio circuits he does himself. In my long life, I have never seen a man so erudite or so really practical.” Even the media took notice. In June 1954, Fortune magazine ran an article featuring the 20 most talented scientists under 40; Pitts was featured, next to Claude Shannon and James Watson. Against all odds, Walter Pitts had skyrocketed into scientific stardom.

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