Pitts stayed hidden until the library closed for the evening. Alone, he wandered through the stacks of books until he came across Principia Mathematica, a three-volume tome written by Bertrand Russell and Alfred Whitehead, which attempted to reduce all of mathematics to pure logic. For three days he remained in the library until he had read each volume cover to cover—nearly 2,000 pages in all—and had identified several mistakes. The boy drafted a letter to Russell detailing the errors. Not only did Russell write back, he was so impressed that he invited Pitts to study with him as a graduate student at Cambridge University. Pitts couldn’t oblige him, though—he was only 12 years old
This is a fascinating story about someone I had never heard of before. Walter Pitts was born to a working-class family in Detroit, and had taught himself Greek, Latin and high-level mathematics by the age of 12. After getting the letter from Bertrand Russell, he eventually ran away to Chicago and found odd jobs at the university, until he met Warren McCulloch, a 42-year-old, chain-smoking philosopher poet who “lived on whiskey and ice cream and never went to bed before 4 a.m.” At the time, Walter was just 18, a shy young man with a squat, duck-like face.
McCulloch was trying to come up with a mental model of the brain, and a paper by Alan Turing convinced him the brain was a computing machine, and the functioning of the neurons could be modeled just like the Principia modeled complex mathematics. He and Pitts started working on it, and Pitts moved into McCulloch’s house in a suburb of Chicago. Together, they described what would become an entire field of mathematics and computing called “neural networks.”
Soon, Pitts had also impressed Norbert Weiner, one of the leading scientists at MIT and the father of cybernetics. Weiner was so taken with Pitts’ ability that he promised him a PhD in mathematics, despite the fact that he had never graduated from high school. He soon started collaborating with John von Neumann, a leading Princeton mathematician and physicist and one of the inventors of the first “stored program binary computing machine.” Von Neumann used Pitts’s theories about a mathematical model of memory to design the modern computer. McCulloch described Pitts this way:
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.”
McCulloch made it to MIT as well, and he and Pitts started working together again. But Wiener’s wife disapproved of the late-night parties at McCulloch’s farm in Connecticut, where whiskey flowed and everyone went skinny-dipping. She told Wiener that several of McCulloch’s friends had tried to seduce their daughter Barbara, who was staying at McCulloch’s house in Chicago. Wiener cut off Pitts, and Pitts sank into depression. He started drinking heavily, never finished his PhD and eventually set fire to his notes and papers. He died of cirrhosis of the liver in 1969, at the age of 53.