|Karl Popper ; Ludwig Wittgenstein|
In Conjectures and Refutations, Popper says: “If Wittgenstein's doctrine is true, then nobody can philosophize, in my sense. Were this my opinion I would give up philosophy. But it so happens that I am not only deeply interested in certain philosophical problems (I do not much care whether they are 'rightly' called 'philosophical problems'), but possessed by the hope that I may contribute—if only a little, and only by hard work—to their solution.”
However, Popper holds that Wittgenstein's idea of eradicating philosophy (and theology) with the help of an adaptation of Bertrand Russell's theory of types was ingenious and original. He says that the school of linguistic analysis is inspired by Wittgenstein’s idea that there are no genuine philosophical problems, and that the philosophers task is to analyze and explain the linguistic puzzles that have been proposed by traditional philosophy.
In October 1946, Popper gave a lecture at Cambridge. Wittgenstein was present along with Russell and others, when Popper posed the question: “Are There Philosophical Problems?” Perhaps Popper’s tone was too provocative, because Wittgenstein was incensed. An angry exchange ensued between them. According to Popper's own account, Wittgenstein had in his hand a red hot poker, which he brandished like a conductor’s baton to emphasize his points. Russell told him to put down the poker. Wittgenstein complied and marched out of the room, slamming the door behind him.
Popper has a lot to say about Wittgenstein's Tractatus. Here’s one passage from Conjectures and Refutations:
Wittgenstein, as you all know, tried to show in the Tractatus that all so-called philosophical or metaphysical propositions were actually non-propositions or pseudo-propositions: that they were senseless or meaningless. All genuine (or meaningful) propositions were truth functions of the elementary or atomic propositions which described 'atomic facts', i.e.--facts which can in principle be ascertained by observation. In other words, meaningful propositions were fully reducible to elementary or atomic propositions which were simple statements describing possible states of affairs, and which could in principle be established or rejected by observation. If we call a statement an 'observation statement' not only if it states an actual observation but also if it states anything that may be observed, we shall have to say that every genuine proposition must be a truth-function of, and therefore deducible from, observation statements. All other apparent propositions will be meaningless pseudo-propositions; in fact they will be nothing but nonsensical gibberish.In this passage, Popper talks a great deal about “observation,” but he does not mention the “picture theory of language,” which is the crucial element of the Tractatus.