Irreverent and electrifying, when A.J. Ayer’s epoch-making work was published in 1936 it shook the foundations of British philosophy, and made its author notorious. He argues that if you cannot prove a statement by scientific methods, or by experience, it is literally meaningless. In this sense, everything else – morals, aesthetics, religion, philosphy itself – becomes nonsensical. For example, to say that murder is wrong is a meaningless statement – you are simply saying that you do not like it. Ayer’s shocking argument, known as Logical Positivism, was a direct challenge to orthodox morality. Yet it became a classic text, revitalizing British philosophy and setting it on an entirely new course.