Wittgenstein has his interlocutor ask, “How many kinds of sentence are there? Say assertion, question, and command?” Wittgenstein's response is that there are countless kinds: countless different kinds of use of what we call “symbols,” “words,” “sentences.” And, he goes on, “this multiplicity is not something fixed, given once for all; but new types of language, new language-games, as we may say, come into existence, and others become obsolete and get forgotten.”

Ryle, for his part, constantly reminds his readers that sentences have a great number of different employments besides those of stating, asserting, describing, or reporting. (Commanding, cajoling, deriding, punishing, congratulating, praising, promising, giving vent, and expressing are just a few.) In particular, he urges,

As this anticipates, among the kinds of sentences that interest philosophers are ones whose primary aim, in the context of their use, is explanatory, justificatory, or actionguiding. Among such sentences may be those expressing laws, rules, dispositions, definitions, principles, or norms.

Now some of these sentences may be classified by logicians as statements, and thus, as truth-apt. “Murder is wrong,” “Any two bodies in the universe attract each other with a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between them,” and “John wants me to replace the bottle of Chablis I drank” are examples. But though they are evaluable as true or false and, indeed, that they are so evaluable is required for syntactic operations upon these sentences, this “surface grammar” tends to mislead philosophers. Overly impressed with their logical classification, they find themselves looking in the wrong place for the facts they are alleged to state, which are supposed to render the sentences true. When they cannot find them among what Ryle calls “witnessable events,” they tend to suppose they must be found among “unwitnessable” ones.