ABSTRACT
Throughout his career, Wittgenstein propounded two main claims concerning nonsense. First, all metaphysics is nonsensical. The proper task of philosophy is not to answer metaphysical questions by producing theses, doctrines or theories, but to show that they rest on conceptual confusions. Second, ‘the negation of an a priori proposition’, e.g. ‘7 + 5 = 12’ or ‘Some objects are red and green all over at the same time’, is not a necessarily false proposition, but a nonsensical combination of signs (see §§251-2). By the same token, the a priori or necessary propositions themselves do not exclude a genuine possibility, since in their case no such possibility can meaningfully be specified (TLP 3.03-3.05; AWL 139-40, 165-6). Instead, the later Wittgenstein argued, such propositions ban a certain combination of words as meaningless from our language. Necessary propositions are not necessary truths, but norms that exclude certain sign combinations from our language.
