With the bullies from school hot on his trail, a terrified 12 year-old **Walter Pitts** dashed into a silent Detroit Public Library.

18 years later, a grown-up **Walter Pitts** would co-author a shocking paper with some of the the Mount Rushmore of Computer Science. His paper in 1942 with Warren McCulloch and Jerome Lettvin — ** What the Frog’s Eye Tells the Frog’s Brain** — would forever change the landscape of Computing, AI, and human thought, although not in the way they could have ever have imagined…or intended.

#### Luck is what happens when Preparation meets Opportunity.

By the time **Walter** stumbled upon the **Principia Mathematica** (“PM”), he was already a self-taught child prodigy. Having absorbed Greek, Latin, and Sanskrit, **Walter** had prepared himself for the biggest challenge of his life. From the instant he began reading, Walter was hooked, and he finished the massive, 2,000 page PM in just two weeks.

The Principia Mathematica attempted to create a ‘bible of mathematics and logic, from which all mathematical and logical ideas could be derived.’

**The Value of Good Sources**

The Principia Mathematica by **Alfred North Whitehead** and **Bertrand Russell** is the most influential mathematical and logical treatise of the 20th century. Think of a Bible written without the assumption of an alphabet. It was the biggest challenge of the early 20th century, and **Whitehead and Russell **set out to do the impossible.

In writing Principia Mathematica, one of Russell’s principal objectives was to give evidence that all of mathematics really could be derived from logic. — Steven Wolfram

Following **Newton’s Philosophiæ Naturalis Principia Mathematica**, global academia was convinced that they could uncover all of Nature’s Secrets by reducing the world to the orderliness of mathematics, logic, equations of absolute truth. The Principia Mathematica set out to be THE symbolic, mathematical, logical theory of everything upon which all other truths about Nature could be built.

#### Whitehead & Russell Keep It Thorough

**Whitehead & Russell **took the challenge so seriously that they famously filled 360 pages to prove that — once and for all — 1 + 1 = 2. Their exhaustive treatise on logic would form the basis of all Artificial Intelligence and Computing Innovation for the next 100 years, although not in the way they could have ever have imagined…or intended.

Young Walter, all alone in the library but safe from the interference of the bullies from school, began making notes as he read. Two weeks later, Walter sent a letter to Bertrand Russell…with corrections.

#### Russell received the letter, and was so impressed that he responded to Pitts as if he was a fellow academic. In the letter, he offered Russell a chance to study with him — Walter turned him down. Russell didn’t even know that Walter was 12.

### Chicago — The Birthplace of more than Just Kanye West

Three years later, at just 15 years old, Walter ran away from home and escaped to Chicago. He’d never see his parents again. Walter learned that Bertrand Russell had traveled from University of Cambridge in England and had begun teaching at the University of Chicago. Walter wanted to study directly under Bertrand Russell, live and direct.

There was just one problem: Walter Pitts was broke and homeless. There was no way he was going to be able to afford the hefty tuition at the lead University in America’s third-busiest mega-city. So, Walter did what any would-be student would do: he showed up to one of the University Professors’ office and did the same thing he did to Russell — show him where he messed up.

Rudolph Carnap — still a legendary logician today — had recently published “The Logical Syntax of Language.” Walter showed up to Carnap’s office — without permission — and proceeded to explain to Carnap where his logical syntax didn’t make any sense. Once he was finished showing Carnap where he messed up, in typical Pitts fashion, left the building, leaving Carnap to light a piece of his thesis on fire.

Walter had run away from home in Detroit the previous year and become a nonstudent at the University of Chicago. The school was well aware of him and turned a blind eye to his presence in classes. Before we met, he had wandered into the office of Carnap, the logician, with a marked and annotated copy of Carnap’s recently published book on logic. Without introducing himself he went into a careful analysis of weaknesses and even outright errors in the text, and after a long colloquy, he left without ever giving his name. Carnap spent half a year searching for “that newsboy who understood logic,” and when he found Walter, arranged to get him a job (for Walter was penniless). In any case, nobody threw him out of the graduate school classes he attended. — The History of Neuroscience in Autobiography

In 1935, when a 15 year-old janitor began sneaking into Bertrand Russell’s Philosophy, Math and Logic lectures at the University of Chicago, nobody chased him away. After all, the young Walter had a ring of protection around him called Professor Carnap and Professor Russell, two of the most celebrated thinkers of the 20th century.

Now, as opposed to life in Detroit hunted by high-school bullies, Walter began swimming in a school of his intellectual peers. He was soon discovered by Warren McCulloch and Jerome Lettvin, Researchers and Inventors who would call on Walter’s mathematical genius to test and publish the one of the most shocking and least understood paper’s in the history of science: What The Frog’s Eye Tells The Frog’s Brain.

### Thesis Meets AntiThesis

#### If the Principia Mathematica was a Thesis, Kurt Godel’s Incompleteness Theorem was it’s AntiThesis.

As it turns out, Pitts wasn’t the only person pouring over the Principia Mathematica. In fact, none of the work by Levitt, McCullogh, or Minsky would have been possible with PM.

The Principia Mathematica attempted to create a ‘bible of mathematics and logic, from which all mathematical and logical ideas could be derived.’

20 years later, Godel’s Incompleteness Theorem, showed that the Principia Mathematica — or any such attempt at creating a bible of math and logic from which all mathematical and logical ideas — was impossible. There would always be inconsistencies, no matter how true the individual statements were.

The resolution, or SynThesis/Aufhebung between the Whitehead & Russell’s Principia Mathematica and Godel’s Incompleteness Theorem lead to the revolutionary and radically emergent Turing Computer and the Church-Turing Thesis.

Many people think that Godel’s Incompleteness Theorem washed away all relevance of the Principia Mathematica. If that were true, Godel would have never continued contributing to the eternal study of Russell’s work. In fact, Godel himself attempted a mathematical proof for the existence of God.

From 1943 onward, Godel became increasingly interested in philosophy and relativity theory. In 1944, he contributed a study of Russell’s mathematical logic (see §X– Principia) to the Russell volume in the Library of Living Philosophers.

### Inducting The Foundations Of Math Into The Sky

In 1942, while Godel, Russell, and Whitehead had moved onto Philosophy, a grown-up Walter Pitts and the elder Warren McCulloch published their groundbreaking, “On the Logical Calculus Immanent in Nervous Activity” which served as the basis for AI research.

The first work that is now generally recognized as AI was done by Warren McCulloch and Walter Pitts (1943). They drew on three sources: knowledge of the basic physiology and function of neurons in the brain; the formal analysis of propositional logic due to Russell and Whitehead; and Turing’s theory of computation. — Stuart Russell and Peter Norvig, AI, a Modern Approach

At the end of the paper, McCulloch-Pitts cited just three sources, all which are inextricably linked to Whitehead & Russell’s Principia Mathematica:

This paper by McCulloch-Pitts became a key foundation for Artificial Intelligence.

It was there, late in that year (1942), that Warren and Walter conceived and wrote their famous paper, “On the Logical Calculus Immanent in Nervous Activity,” and its sequel, “How We Perceive Universals.” These papers are at the root of what later became AI, artificial intelligence. They were published in Rashevsky’s Bulletin of Mathematical Biophysics. It is hard to describe the ferment in those long evenings, but for the first time I began to perceive what was at issue in the study of the brain. — Lettvin, The History of Neuroscience in Autobiography, Vol. 2, Larry Squire

### Inducting the Foundations of Math into the Eyes and the Brain

Four years after McCulloch Pitts published ‘On the Logical Calculus Immanent in Nervous Activity’, Lettvin wanted to test an assumption.

“The assumption has always been that the eye mainly senses light, whose local distribution is transmitted to the brain in a kind of copy by a mosaic of impulse….” — Lettvin

The assumption at the time — and the assumption that is largely believed today — is that the brain is the sole information processor in the human body.

By attaching electrodes to a frog’s optic nerve, the team of Lettvin, McCulloch-Pitts, and Maturana discovered something shocking: the frog’s eye doesn’t simply send information to the frog’s brain for processing. Lettvin’s research showed that the frog’s eye was playing a huge role in the interpretation of information. The brain wasn’t the only calculator helping the frog catch flies.

Quote

In short, Lettvin’s group discovered that a lot of what was thought to happen in the brain actually happened in the eye itself. “ The eye speaks to the brain in a language already highly organized and interpreted, instead of transmitting some more or less accurate copy of the distribution of light on the receptors,” he concluded.

What a Frog’s Eye Tells the Frog’s Brain shocked everyone. Well, humored is a more accurate description.

We were laughed off the stage, literally, at the American Physiology Society in Atlantic City, where we tried to present it,” Lettvin told his collaborator Luis Amador in 1986.

Even after the paper was published in 1959, the findings met with considerable skepticism. One disgruntled scientist — fellow MIT researcher Walter Rosenblith — ”felt we were … liars, held a meeting on perception, visual perception, and didn’t invite us,” Lettvin told Amador. Another colleague circumvented the snub by taking conference attendees on an unannounced visit to his lab so they could see for themselves how the experiment was done. The visiting audience was convinced, and Rosenblith soon apologized. “And that,” Lettvin concluded, “was the time that we began to be taken seriously.”

The paper was so shocking that it made Danny Hillis QUIT neurobiology before he even began. Phew! Danny Hillis now holds over 300 patents in computer science and is another head on the Mount Rushmore of Computer Science forever indebted to McCullough-Pitts and Lettvin.

DID YOU KNOW: Jerome Lettvin once ghost-wrote pamphlets for the YCL, the Young Communist League, to practice ‘putting forth vehemently what I don’t believe, but he [Warren McCulloch] and Walter persuaded me to stop.’

### The Triumph of AI

The Synthesis between the Principia Mathematica and Godel’s Incompleteness Theorem provided the Foundation for all of Computer Science & Artificial Intelligence Research & Development.

With the limits of logical reasoning now on full display, the following inventions burst forth:

- Turing’s Machine
- Church’s Lambda Calculus
- McCullogh-Pitts’ On the Logical Calculus Immanent in Nervous Activity
- Whitehead’s Theory of Relativity in opposition to Einstein
- Whitehead’s Process Philosophy and the Philosophy of the Organism

The Synthesis between the information processing in the Frog’s Eye vis a vis the information processing in the Frog’s Brain was shocking.

The eye speaks to the brain in a language already highly organized and interpreted, instead of transmitting some more or less accurate copy of the distribution of light on the receptors,” he concluded.

It meant that studying the brain would only give you a partial ideas of what the human was thinking and feeling.

What The Frog’s Eye Tells the Frog’s Brain is a critical idea in computer science. It shows that information processing happens at the edge of the human body — in the eye (and the hands, tongue, nose…?) — not just in the brain.

In fact, the most prolific Venture Capital firm in the world, Andreessen Horowitz, is leveraging these ideas in conjunction with OODA Loops to create an entire new industry in computing that could be more valuable than Cloud Computing — Edge Computing.

### The Tragedy of AI

And young master Pitts? The master mathematician and logician that escaped high-school bullies to invent with the geniuses of geniuses at the University of Chicago, Kellex, and MIT?

“Would I had him with me always.” — McCulloch

Pitts has a short, prolific career. Too short, too prolific. Having abandoned his parents in Detroit, his new colleagues became his family

After his landmark publication in 1942 with McCullough, Pitts was snapped up for two years as a Mathematician for the Manhattan arm of the atomic bomb project.

“I now understand at once some seven-eighths of what Wiener says, which I am told is something of an achievement,” Pitts wrote in a letter to McCulloch in December of 1943, some three months after he’d arrived. His work with Wiener was “to constitute the first adequate discussion of statistical mechanics, understood in the most general possible sense, so that it includes for example the problem of deriving the psychological, or statistical, laws of behavior from the microscopic laws of neurophysiology … Doesn’t it sound fine?” — Pitts

In this new family, his father figure was Norbert Wiener, a Scientist who was heavily influenced by the writings of Whitehead & Russell.

His [Norbert’s] PhD thesis was in mathematical logic….Schmidt [his academic supervisor] suggested for his topic a comparison between the algebra of relatives of Schroeder and that of Whitehead and Russell (see Norbert, On Ordered Pairs, 1914). Wiener found the work easy although later, under Russell, “I learned that I had missed almost every issue of true philosophical significance”. During [Norbert’s] last year at Harvard he applied for and was awarded a travelling fellowship which he decided to use by studying with Bertrand Russell at Cambridge University. [Norbert] was soon to be 19-years old.

Lettvin introduced Pitts to Wiener as his new right-hand scientist when Wiener’s previous student died suddenly in a skiing accident.

[Walter Pitts is] without question the strongest young scientist whom I have ever met … I should be extremely astonished if he does not prove to be one of the two or three most important scientists of his generation, not merely in America but in the world at large.” — Dark Hero of the Information Age: In Search of Norbert Wiener, The Father of …

After World War II, Pitts was happy to reunite with his father figure Norbert Wiener and Warren McCulloch, his partner in crime. The three planned on finalizing deciphering the mysteries of the brain and of knowledge itself.

Alas, God laughs at man’s plans.

There was just one person who wasn’t happy about the reunion: Wiener’s wife. Margaret Wiener was, by all accounts, a controlling, conservative prude — and she despised McCulloch’s influence on her husband. McCulloch hosted wild get-togethers at his family farm in Old Lyme, Connecticut, where ideas roamed free and everyone went skinny-dipping. It had been one thing when McCulloch was in Chicago, but now he was coming to Cambridge and Margaret wouldn’t have it. And so she invented a story. She sat Wiener down and informed him that when their daughter, Barbara, had stayed at McCulloch’s house in Chicago, several of “his boys” had seduced her. Wiener immediately sent an angry telegram to Wiesner: “Please inform [Pitts and Lettvin] that all connection between me and your projects is permanently abolished. They are your problem. Wiener.” He never spoke to Pitts again.

Returning to the conditions at MIT Walter, as I said, fled his home in his early times because of his father. Warren and I were his close friends but Wiener became the father he never had. One day, in 1952, Wiener sent from Mexico City a registered letter to Jerry Wiesner severing forever all relations with Warren, Walter, and me. Years later, Arturo Rosenblith, at whose house the Wieners had stayed at the time, gave an account of what happened. It is a shameful story; Wiener himself was as much a victim as we. The tale is not worth telling here. But the anathema destroyed Walter. He gradually and politely bowed out of being, lost interest in pretty much everything, and became inaccessible. After the few years that Warren and Rook, then Maggie and I, took him in, he did what he could to disappear in a small rented room where he died after years of unrelieved despair. He had burnt everything he ever wrote. I have often wondered whether I could have done anything. After all, as psychiatrist I could have a found a colleague to take him on. But the problem was that Walter would not go, and in any case was dead of despair long before he died. Wiener was unapproachable on the matter by any of our many mutual friends. — Lettvin

On Saturday, April 21, 1969, his hand shaking with an alcoholic’s delirium tremens, Pitts sent a letter from his room at Beth Israel Hospital in Boston to McCulloch’s room down the road at the Cardiac Intensive Care Ward at Peter Bent Brigham Hospital. “I understand you had a light coronary; … that you are attached to many sensors connected to panels and alarms continuously monitored by a nurse, and cannot in consequence turn over in bed. No doubt this is cybernetical. But it all makes me most abominably sad.” Pitts himself had been in the hospital for three weeks, having been admitted with liver problems and jaundice. On May 14, 1969 Walter Pitts died alone in a boarding house in Cambridge, of bleeding esophageal varices, a condition associated with cirrhosis of the liver. Four months later, McCulloch passed away, as if the existence of one without the other were simply illogical, a reverberating loop wrenched open.