<p>The mathematical genius Frank Ramsey—whose work in subjective probability and partial belief laid the groundwork for the Bayesian updating at the core of behavioral AI—once jotted down a striking remark in his diary. “Metaphysics reflects itself in psychology unless a very strange psychology is adopted e.g. behaviorism.” Then, he added between parentheses: “behaviourism is not false as far as I know; but it is insane.” The young man—Ramsey died tragically before the age of 27—made major contributions to logic and economics. Though economists inspired by him ignored his skepticism toward behaviorism and relied exclusively on observable behavior, Ramsey counter-balanced his own behaviorist models with his interest in depth psychology, i.e., Freudian psychoanalysis, which, after a visit to Vienna, he believed cured his own anxieties.</p>