Textbook of AI

1898–1969, Neurophysiologist, cybernetician

Also known as: Warren Sturgis McCulloch

Warren McCulloch was an American neurophysiologist and cybernetician who, with the young logician Walter Pitts, wrote the 1943 paper A Logical Calculus of the Ideas Immanent in Nervous Activity. The paper proposed a mathematical model of an idealised neuron, a binary threshold unit that fires when the weighted sum of its inputs exceeds a threshold, and showed that networks of such units could implement any expression of propositional logic. It was the first mathematical theory of neural computation and the direct ancestor of the perceptron, of artificial neural networks, and of the connectionist tradition that culminated in modern deep learning.

McCulloch took his medical degree at Columbia in 1927 and trained in neurology. He chaired the Department of Psychiatry at the University of Illinois Medical School in Chicago from 1941 to 1951 before moving to MIT, where he led the Research Laboratory of Electronics until his retirement. He was president of the Macy Conferences on Cybernetics (1946–1953), the interdisciplinary meetings, drawing in Norbert Wiener, John von Neumann, Claude Shannon, Margaret Mead, Gregory Bateson, Heinz von Foerster and others, that founded cybernetics as a field.

McCulloch was an ebullient and theatrical figure, known for his white beard, three-piece suits and aphorisms ("What is a number that a man may know it, and a man that he may know a number?"). His collaboration with Pitts produced further landmark papers including the 1947 How We Know Universals, on translation-invariant pattern recognition in the visual cortex, anticipating themes that would resurface in convolutional neural networks half a century later.