Picture a perfectly rational donkey standing exactly halfway between hay and water, or between two identical piles of hay. With no logical reason to choose one over the other, it freezes and starves. This episode traces how that absurd image became a foundational problem in psychology and a literal hardware hazard in modern computing. We reveal that 14th-century philosopher Jean Buridan never invented the donkey; his critics created it to mock his moral determinism, and the imagery goes back to Aristotle, who used a man equally hungry and thirsty to ridicule Anaximander's theory of a stationary Earth.

We then follow the paradox through the free will debates: Al-Ghazali's two identical dates as proof of free will, Pierre Bayle's everyday arbitrary choices, Spinoza's ruthless acceptance that a perfectly balanced person would die, and Leibniz' ...