Keynes had many plausible things to say about unemployment and its causes. His "mercurial mind," though, relied on intuition, which means that he could not strictly prove his hypotheses. This explains why Keynes's ideas immediately invited bastardizations. One of them, the Phillips curve...

Nineteenth-century British economists Henry Thornton and Walter Bagehot established the classical rules of behavior for a central bank, acting as lender of last resort, seeking to avert panics and crises: Lend freely (to temporarily illiquid but solvent borrowers only) against the security of...