If thinking is a matter of operating with signs, we need to understand what signs are and how they are used. Wittgenstein introduces the notion of a language game, a primitive form of language that uses signs in a simpler, clearer way than our own complex languages. For example, here is a game formed around the command "fetch six apples from the grocer": I give the grocer a piece of paper marked "six apples," and the grocer then looks at his different shelves, matching the word "apple" to the label on one of the shelves. When he has done so, he counts up to six, taking one fruit from that shelf for every number he has counted.
Wittgenstein says we usually avoid the piecemeal approach of language games out of a philosophical craving for generality and a contempt for the particular. Partly inspired by science, we try to reduce language to a handful of laws, and assume that any word has a single meaning or essence that all instances of its use share in common. Wittgenstein takes the example of the word "game" to show up this misconception. There is no one thing that all games have in common. Rather, there is a series of family resemblances. Some games have certain features in common and other games share other common features.
There is no common property of all cases of "wishing" or "expecting," and we shackle ourselves with our drive to identify this nonexistent common property. Wittgenstein runs through a series of examples showing the difficulties in identifying a feeling of tension as the essence of expectation, and also highlights some problems related to assigning a single meaning to the word "fear."
Wittgenstein discusses similar problems with the term "unconscious toothache," a term her creates to describe instances of tooth decay where a person feels no pain. This use of "unconscious" and "know," though unusual, are in themselves unproblematic. The difficulty arises when we try to force these uses into analogy with other uses of "unconscious" and "know" and begin to wonder how unconscious or unknown pain can exist, and ask what counts as a symptom and what counts as a criterion of toothache.
Historically, philosophy has been obsessed with giving words a single, strict definition, and has tied itself in knots over questions like "what is knowledge?" If we find one definition unsatisfactory, we simply replace it with a more complex definition rather than question our motives for seeking a single definition in the first place. Wittgenstein suggests that we must free ourselves from the notion that there is one paradigmatic use of a word. He says, "Philosophy, as we use the word, is a fight against the fascination which forms of expression exert on us" (Wittgenstein, 27). He says we do not need to force language into the tiny boxes of strict rules and definitions. Language is not something forced on us from the outside that we must come to know scientifically. Language comes from ourselves and does not need stricter definition than it has already.
The concept of "language games" is one of the best known features of Wittgenstein's later philosophy. We will see it put to even more prominent use in the Brown Book, and it plays a significant—though perhaps not as central—role in the Philosophical Investigations.