This is one of my favourite pieces of science feature reporting. I lack the background in computer science to better appreciate the technical angles of the story, but for the present, the article made a strong impression because of the underdog story:

"The library was familiar ground, where he had taught himself Greek, Latin, logic, and mathematics—better than home, where his father insisted he drop out of school and go to work. Outside, the world was messy. Inside, it all made sense.

"Not wanting to risk another run-in that night, 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 between 1910 and 1913, which attempted to reduce all of mathematics to pure logic. Pitts sat down and began to read. 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. Deciding that Bertrand Russell himself needed to know about these, 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 in England. Pitts couldn’t oblige him, though—he was only 12 years old. But three years later, when he heard that Russell would be visiting the University of Chicago, the 15-year-old ran away from home and headed for Illinois. He never saw his family again."

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It also made an impact because of its description of the nature of a deep friendship and mentorship: "Pitts had found in McCulloch everything he had needed—acceptance, friendship, his intellectual other half, the father he never had. Although he had only lived in Hinsdale for a short time, the runaway would refer to McCulloch’s house as home for the rest of his life. For his part, McCulloch was just as enamored. In Pitts he had found a kindred spirit, his “bootlegged collaborator,” and a mind with the technical prowess to bring McCulloch’s half-formed notions to life. As he put it in a letter of reference about Pitts, “Would I had him with me always.”"

[...] "Some years earlier, in a letter to McCulloch, Pitts wrote “About once a week now I become violently homesick to talk all evening and all night to you.” Despite his success, Pitts had become homesick—and home meant McCulloch. He was coming to believe that if he could work with McCulloch again, he would be happier, more productive, and more likely to break new ground. McCulloch, too, seemed to be floundering without his bootlegged collaborator."

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The tragic end also left an impression, where the article explores the consequence of creating an identity based on relationships with other people (arguably codependency): "Now, alienated from Wiener, Pitts’ despair turned lethal. He began drinking heavily and pulled away from his friends. When he was offered his Ph.D., he refused to sign the paperwork. He set fire to his dissertation along with all of his notes and his papers. Years of work—important work that everyone in the community was eagerly awaiting— he burnt it all, priceless information reduced to entropy and ash. Wiesner offered Lettvin increased support for the lab if he could recover any bits of the dissertation. But it was all gone."

[...] "Pitts remained employed by MIT, but this was little more than a technicality; he hardly spoke to anyone and would frequently disappear. “We’d go hunting for him night after night,” Lettvin said. “Watching him destroy himself was a dreadful experience.”"

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The loss of the friendship was compounded by Pitts's attempt to substantiate an ambitious goal related to much of the work in his life, but perceiving failure along the way (the results were disproven): "The results shook Pitts’ worldview to its core. Instead of the brain computing information digital neuron by digital neuron using the exacting implement of mathematical logic, messy, analog processes in the eye were doing at least part of the interpretive work. “It was apparent to him after we had done the frog’s eye that even if logic played a part, it didn’t play the important or central part that one would have expected,” Lettvin said. “It disappointed him. He would never admit it, but it seemed to add to his despair at the loss of Wiener’s friendship.”"

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Analysis: On the one hand, it's an amazing story of defying one's likely station in life, through self-study and earning the support of a mentor who takes a chance on you.

But on the other, it's also a tragedy of deeply relying on others, and how a breach in that relationship can cause a negative spiral of thoughts and emotions.

I wonder how Walter Pitts's life would have turned out if he had a wider support network or at least friends, preferably outside of his field of work and in academia (it's possible he may well have, but I didn't read about it in the article). Then, perhaps, the loss of his friendship with Wiener wouldn't have made such an impact, and the negative result also wouldn't have had such a profoundly negative impact, either.

I also wonder why the loss of his friendship with Wiener had such an impact, when he still had the near-lifelong friendship of McCulloch. It's impossible to really know, but perhaps he saw Pitts more as a close friend, and McCulloch more as a family member and mentor.