From a runaway child, to a pioneer in neuroscience, to a reclusive alcoholic.

Walter Pitz was born in Detroit on April 23, 1923. Pitz was bullied as a child by boys in his family and neighborhood. He eventually found refuge in a local library. After that, the library became a familiar environment, where he learned on his own. He did not go to school because his father insisted that he drop out and go out to work.

Eventually Pitz found Principia Mathematica in the library, a three-volume series by two British philosophers, Bertrand Russell and Alfred Whitehead. In the book, the author tries to reduce all mathematics to pure logic. It took Pitz three days to read every page in the series -- nearly 2,000 pages in all -- and note some errors. He thought authors should know about these mistakes, so he wrote Russell a letter. Not only did Russell write back, but he also invited Pitz to be his graduate student at Cambridge University in England. But Pitz didn't go because he was only 12 years old. Three years later, when Pitz heard Russell was going to visit the University of Chicago, the 15-year-old boy left home for Chicago. He never saw his family again.

Build the first brain model

When Pitz arrived at the University of Chicago, he did occasional menial work and attended Russell's lectures whenever he could. There he met a young American medical student, Jerome Letwin, who would become his life and career friend.

In 1940, Letwin introduced Pitz to Warren McCulloch, a new psychiatry professor at the University of Illinois. The first time McCulloch, 42, and Pitz spoke, they immediately realized they had a lot in common. And McCulloch became the most important person in Pitz's life.

At that time, Freudian psychoanalysis took over the whole field of psychology. McCulloch, though a professor of psychiatry, did not believe in Freud's analytical psychology. He believed that mysterious psychological activity came purely from the neural activity of the brain. McCulloch had also read Principia Mathematica and was inspired to try to use logic to build a model of the brain. McCulloch knew that the brain's neurons fire when the stimulus is at or above a minimum threshold (also known as the threshold, which is the lowest or highest value an effect can produce), so he speculated that the brain's working system is binary -- neurons firing or not firing. He believes that neurons are like a binary logic gate, by changing the firing threshold of neurons, can perform a variety of logical operations.

At that time, Alan Turing, a mathematician from England, published a paper demonstrating that machines were capable of calculating any function. McCulloch became convinced that the brain was a machine that calculated with logic.

McCulloch explained his project to Pitz, who immediately understood and knew what mathematical tools were available. McCulloch invited Pitz to stay in his home. Late at night, when McCulloch's wife and children were asleep, McCulloch and Pitz poured whiskey, sat down and began to talk about how logic could be used to build a brain model.

Even before Pitz arrived, McCulloch was in trouble. Neurons will inevitably form a loop so that the output of the last neuron becomes the input of the first -- a network that bites its own tail. From a logical point of view, a cycle looks a lot like a paradox: the conclusion becomes the premise and the effect becomes the cause. McCulloch didn't know how to handle it.

But now Pitz knows how to fix it. He believes that if a person sees a lightning bolt appear in the sky, the eyes send the signal to the brain. The information caused by lightning is instantly fleeting on neurons. But when the message reaches a neural ring, the message containing the lightning will rotate forever in that ring, forming a memory.

After figuring this out, McCulloch and Pitz eventually came up with the world's first model of the brain, and the first to show that the brain is an information processor. Their research showed that by connecting binary neurons into various chains and loops, the brain could perform any logical operation and calculation, similar to the machine that Turing had hypothesized. In addition, the neural loops they discovered shed light on how the brain stores information. Although their model is far too simple for the real brain, McCulloch and Pitz argue that we need not be shrouded in Freudian mysticism and that we have the ability to understand the brain through logic.

Become a science star

Pitz got everything he needed from McCulloch -- approval, friendship, a good friend, even a fatherly warmth he had never had. Although he lived in the McCulloch home for a short time, Pitz called it home for the rest of his life. For McCulloch, Pitz was his most important collaborator, helping McCulloch turn many of his initial ideas into mature ones.

When Pitz arrived at MIT three years later, he made a good impression on someone else, too. That man was Norbert Wiener, mathematician, philosopher and founder of cybernetics. When Pitz arrived, Wiener was doing some math on the blackboard, and Pitz had some questions and suggestions. This led Wiener to admire Pitz and promise him a doctorate in mathematics from MIT, which Pitz accepted. Pitz left the McCulloch home, left Chicago, and, under Wiener's tutelage, began attending the Massachusetts Institute of Technology.

Wiener wanted Pitz to make his brain model more realistic. Although Pitz and McCulloch's work has made some progress, their model is too simple to capture all the features of the real brain. To come up with a model of the brain containing nearly 100 billion neurons, Wiener thought, would require statistical mechanics, and statistical mechanics is where Wiener excels.

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Pitz also realized that while the genetic code was supposed to contain the properties of the nervous system, genes certainly couldn't determine in advance how the brain's nearly 1,000 trillion synaptic links were connected -- that's too much information for genes to hold. He believed that essentially neural networks started randomly, and over time, by changing the threshold of neurons, the randomness would gradually become ordered and information would emerge. He began to study this process using statistical mechanics.

In June 1945, mathematician von Neumann published his famous Draft Report on the EDVAC, in which he proposed using McCulloch and Pitz's brain model to build the world's first binary computer that could store data and programs, known as the EDVAC. He proposed replacing neurons with vacuum tubes, which could be constructed according to the theories of McCulloch and Pitz, and could be used to compute any computable problem. In order to store programs, computers need memory, which requires Pitz's neural ring to do its job. Von Neumann's report marked the dawn of the modern computer age, and it was made possible by the work of McCulloch and Pitz.

In 1946, he began teaching mathematical logic at MIT and went on to work with Wiener on statistical theories of the brain. In the intervening years, Pitz has become a rising scientific star.

The fall of genius

Despite his continued academic success, Pitz missed McCulloch, and so did McCulloch. In 1952, the Massachusetts Institute of Technology invited McCulloch to work on a new project in brain science. Knowing that this was his chance to work with Pitz again, McCulloch decisively gave up his tenured professorship and his big house in Chicago to come to MIT. Pitz, his friend Letwin and others joined the project.

But one person wasn't happy about McLoch's arrival: Wiener's wife. Wiener's wife was a conservative woman, and she feared that the uninhibited McLoch would influence her husband. So she made up a story about someone in McLoch's group hitting on their daughter. Wiener immediately became so popular that he canceled all of his projects with McLoch's group and never spoke to Pitz again or told him why. Weiner had been a father to him, and now she abandoned him for no reason. It's not just a loss. This is worse than it seems: it doesn't follow logic.

And then there's the frogs. The MIT basement is full of crickets, and Letwin has a colony of frogs. Biologists at the time believed that the eyes acted like photographic plates, passively recording light spots and sending this information to the brain. Letwin decided to test it.

Letwin, Pitz, McCulloch and others found that frogs' eyes not only record what they see, but also filter and analyze visual information such as contrast, curvature and motion. In other words, the information from the frog's eyes to the brain has been processed. In 1959, they published their findings in a paper called "What Frog Eyes Tell Your Brain." This paper has become one of the most cited.

The above research suggests that the visual cells of the frog eye do more than just react passively to light. They also have some other function, so the frog eye is not strictly an on-off logical device. This shook the core of Pitz's worldview, which was that the activity of neurons could be fully described by pure logic. This, and Wiener's disconnection from him, sent Pitz spiraling into depression. He began drinking heavily, ran away from his friends, didn't want his Ph.D. from MIT, and set fire to his doctoral thesis and all his notes and papers. Pitz's important years of work, from information to entropy and soot.

After that, though still employed by MIT, Pitz rarely spoke to anyone and often disappeared. Letwin and his men had to search for him night after night. In a way, Pitz was still like a 12-year-old to them, constantly beaten, constantly running away, constantly hiding in the library. But instead of a book, he had a bottle in his hand.

On April 21, 1969, Pitz's hand was shaking with delirium tremens while he was in the hospital, but he also wrote a letter to McLoch, who was in another hospital. Pitz was diagnosed with liver disease and jaundice and spent three weeks in hospital. Pitz died alone in his apartment on May 14, 1969. McCulloch died four months later.