Edward Fredkin

Edward Fredkin (1934–2023) may be the only person ever to become a full MIT professor with no degree at all. College dropout, Air Force jet pilot, self-taught programmer, tech millionaire, owner of a private Caribbean island — and the man who looked at the universe and said, with total sincerity: this is a computer, and we're the program.

From cockpit to professorship

Fredkin dropped out of Caltech, flew fighter jets for the Air Force, and got assigned to an early computer project — where he discovered he could program better than almost anyone alive. He founded Information International Inc., one of the first companies to get computers talking to film and images, and made a fortune (hence the island — Moskito, in the British Virgin Islands, later sold to Richard Branson). MIT, faced with a degree-less autodidact who out-thought its faculty, simply made him a full professor and put him in charge of Project MAC, its flagship computing lab. Colleagues joked, half-exasperated, that Fredkin had more ideas per day than most researchers have per year — the trouble was catching one and pinning it down before the next ten arrived.

Fredkin's grandest idea was digital physics: the conviction that the universe isn't like a computer — it is one, a giant cellular automaton whose cells tick away beneath the smallest scales, and whose running program produces atoms, stars and us. Most physicists scoffed. Richard Feynman didn't: the two became close friends at Caltech and argued about it for years, Feynman poking holes, Fredkin patching them. Feynman's own musings on simulating physics with computers — which helped launch quantum computing — grew partly out of those arguments. Digital physics remains unproven and probably unprovable. Fredkin was entirely untroubled by this.

Billiard balls and a gate with his name on it

To show that physics-like computation was possible, Fredkin invented the Fredkin gate — a controlled swap that never destroys information and never even changes the number of 1s, the heart of his and Tommaso Toffoli's conservative logic. Their most delightful creation: the billiard-ball computer, a machine made of nothing but perfectly bouncing balls, whose collisions compute anything a laptop can — friction-free, in principle spending no energy at all. It was meant as a thought experiment about physics and computation; it ended up furnishing quantum computing with one of its standard gates.