1. The concepts of human nature, natural human reactions and interests, and human natural history are pervasive in Wittgenstein's later philosophy. The idea that our language-games rest on ‘very general facts of nature’ (PI, PPF §365), or that if certain things were different from what they are ‘our normal language-games would thereby lose their point’ (PI §142), is an important theme of his later work. The notions of form of life and language-game, and the emphasis on our everyday practice, our education and training, and the application of linguistic techniques all serve to draw the reader's attention to ‘the spatial and temporal phenomenon of language’ (PI §108), to our life with language, to language as it is woven in with a multitude of human activities. The emphasis on description, on attention to particular cases, on coming to command a clear view of our use of expressions, and the suspicion of abstraction and idealization are fundamental to the later Wittgenstein's conception of philosophical method. In all these ways, and for all these reasons, Wittgenstein's later philosophy gives a strong impression of embodying some form of philosophical naturalism: it is concerned not with questions of justification or with foundations but with a realistic understanding of what we do. However, the questions of exactly what form Wittgenstein's naturalism takes, and of exactly what role it plays in his philosophy, are not easy to answer. Yet the issue is central for the interpretation of Wittgenstein's work. It is, for example, key to the interpretation of his remarks on rule-following and his treatment of psychological concepts, the topics I will focus on in this chapter.

2. Exploiting the naturalistic strand in the later philosophy has been central to attempts to reply to Kripke's claim that Wittgenstein's work contains the ingredients for the construction of a sceptical argument whose conclusion is that there are no facts about meaning, that there is nothing that makes the attribution of meaning, either to oneself or to another, true.