Karl Popper and Ludwig Wittgenstein were two of the greatest philosophers of the twentieth century. The account of their one and only meeting at Cambridge in 1946 has become legendary for the aggressive disagreement between the two men. Peter Munz, an eye witness to the great dispute, is the only person in the world to have been a student of both Popper and Wittgenstein. Here he describes their philosophical relationship as he experienced it. Munz argues that the later Wittgenstein and Popper ought to be seen as complementing one another. Popper believed that when truth is discovered meaning will take care of itself. However, since, in Popper's view, we can never verify a general proposition, we can never be certain of its truth. There must therefore be a way of understanding what it means even though we cannot be sure of its truth. The post-Tractatus Wittgenstein enables us to see how propositions are meaningful regardless of whether we can ascertain their truth and thus fills a gap in Popper's philosophy. At the same time, Popper was able to make up a deficiency in Wittgenstein's later philosophy.
While Wittgenstein had had it that meaningful propositions can be generated in any social order, Popper showed that if propositions are to be true as well as have meaning, the socio-political order in which they are put forward, has to be free and open. Popper and Wittgenstein were barking up the same tree. Though they had much to learn from each other, their personalities stood in the way. Munz imaginatively reconstructs a dialogue to show how the conversation ought to have gone on that famous evening at the Moral Sciences Club in Cambridge in 1946 and then sets out in detail the philosophy that would result from a synthesis of these two great men.