There are two kinds of meaningful statement: analytic statements (as in mathematics), which are true by definition; and statements that can be verified by experience. But if that is so, a very great deal of traditional philosophy, including ethics, aesthetics and metaphysics and also theology is concerned with statements that are literally nonsensical. That extraordinary conclusion is at the heart of this epoch making Positivism. In 1936 it was like a breath of fresh air; over half a century later its power to shock remains undiminished.