In 1964, when social engineering was in its prime, all the best people were positivists, or so a first-year graduate student in economics would naturally have believed. Among philosophers the doctrines of strict positivism were moribund. Philosophical positivism had had its day in the 1920s. One of the headings of Karl Popper's intellectual autobiography, Unended Quest (Popper 1974 [1976], pp. 87f) asks “Who Killed Logical Positivism?” He answers, “I fear that I must admit responsibility.” I, said the Popper, / With my little chopper, / I killed logical positivism. His book of 1934, written when he was about thirty and translated into English twenty-five years later as The Logic of Scientific Discovery (Popper 1934 [1959]), was the knell. Popper quotes the Australian philosopher John Passmore as writing in 1967 that “Logical positivism, then, is dead, or as dead as a philosophical movement ever becomes” (Passmore 1967, p. 56). Even the broader doctrines of logical empiricism under which positivism sheltered had by 1964 been under attack for a long time. W. V. Quine's “Two Dogmas of Empiricism” had in 1951 undermined the distinction inherited from Kant between analytic and synthetic statements. Hilary Putnam dates the reign of positivism from 1930 to about 1960 (Putnam 1990, p. 105).