The Man Who Buried His Teacher — Bryan Carter

The output layer was erased before anyone checked whether it worked.

Earlier this week, I wrote about Walter Pitts and Srinivasa Ramanujan. A teenage runaway from Detroit and a clerk from Madras whose work sits under large parts of the mathematical world that made modern AI possible. Neither of them could get hired today. A lot of people engaged with that post.

What I didn’t tell you is how Pitts died at 46 believing his life’s work was a failure, or how the field he helped found was buried for twenty years with help from someone shaped by his work.

In 1943, Pitts and neurophysiologist Warren McCulloch published “A Logical Calculus of the Ideas Immanent in Nervous Activity,” one of the foundational papers in the neural network lineage behind today’s AI boom. McCulloch had taken the homeless boy in off the streets of Chicago. They worked together every night.

A young man named Marvin Minsky learned from them.

Minsky built his early neural net computer under their influence. He wrote his Princeton doctoral thesis on self-organizing networks in 1954. He got his Harvard fellowship with the support of McCulloch, Norbert Wiener, and Claude Shannon. He built his career on the foundation that Pitts and McCulloch laid.

Then he buried their field.

Minsky did not single-handedly kill neural networks. Connectionism survived in pockets. The practical revival of the paradigm depended on advances in compute, data, and algorithms that hadn’t arrived yet. The first AI winter involved broader UK and US funding politics that extended well beyond one book.

But Minsky did something more durable than killing a field outright. He gave the funding establishment a technically respectable reason to stop taking it seriously.

In 1969, Minsky and Seymour Papert published Perceptrons, a book that demonstrated the mathematical limitations of single-layer neural networks. The critique was narrow and technically correct. Single-layer perceptrons cannot solve the XOR problem. They cannot learn non-linearly separable functions. This was known. What Minsky and Papert did was frame a limitation of the simplest possible architecture as a fundamental indictment of the entire connectionist paradigm.

They knew multi-layer networks could solve XOR. The possibility was not unknown. Minsky himself later acknowledged the critique had been over-applied. But Perceptrons was not written as a technical paper exploring the boundaries of a promising approach. It was written as a permission slip for the people holding the checkbooks.

Rebecca Skinner, writing from Stanford’s archives in 1997, documented the aftermath:

“The devastation of the field of neural net research in 1968 was accomplished almost single-handedly by a harsh critique by Marvin Minsky and Seymour Papert of MIT. The neural net and connectionist paradigm, as dependent on research funding as any other field, was laid waste. The AI establishment at the time was so tight-knit that funding for this type of research was not to be found for two decades.”

Two decades. An entire branch of research, the branch that would eventually produce the technology reshaping every industry on earth right now, was marginalized for twenty years. Not because one man decreed it. Because one man published a narrow critique and the funding apparatus he was embedded in treated it as the final word.

Minsky himself acknowledged the overkill in a cover article in AI Magazine in July 1991. By then the damage had been done for a generation.

To understand how one book could sideline an entire research paradigm, you have to understand the funding structure.

The Advanced Research Projects Agency, DARPA, was AI’s rich uncle. Through its Information Processing Techniques Office, DARPA underwrote practically all formative AI research for three decades. ARPA spent more on AI than the rest of the world combined, and most of that money went to two places: MIT and Stanford.

The first IPTO director was J.C.R. Licklider. Licklider came to DARPA from MIT. He showered MIT with government money. Then he went back to MIT to run Project MAC, the ARPA-funded program that Minsky’s AI group had been incorporated into. Then he returned to DARPA for a second term as director.

Thomas Haigh, writing in the ACM’s Communications in 2023, called the arrangement “a little too cozy by modern standards.” That is an understatement that would make a diplomat blush. It was a revolving door between the people writing the checks and the people cashing them, and the same names show up on both sides.

Skinner’s manuscript describes the result: “DARPA funding and institutions led to the consolidation of an ‘invisible college,’ the so-called ‘Artificial Intelligentsia,’ who determined what was to be done and not done.”

What was to be done was symbolic AI. What was not to...