1. The last two chapters have carried me so far afield that I must now try to relate what I have there said to the previous discussions of informative language and of logic, and to indicate shortly what I have tried to do in the whole book.
I began by discussing four principal kinds of language: the language of empirical propositions, necessary principles, moral and ethical judgments, and poetry. I have tried to show that all these can be explained by two quite different functions for which language is used; it may inform and it may affect the emotions. The long discussion of the necessary propositions of philosophy, mathematics and logic, was designed to show that these propositions both inform us about language-customs and also make recommendations about language (Chapter VII). The discussion of Value Propositions was necessary in order to show that we have not here something quite different from information; that to assess the value of something cannot be contrasted sharply with describing its properties: for value-propositions do tell us certain properties of things, viz. the way in which they may help or hinder human happiness. But they convey information in words which inevitably affect our attitude towards the things described--tend to make us favour them or oppose them, seek them or shun them. So that a valueproposition may be highly persuasive--whether it happens to make a true statement or a false one.
2. My principal conclusion about Informative Language is that all such language is about what we may experience. The language of the physical sciences, I have argued, is about what any normal observer might perceive through his five senses; and 'a physical property' just is that to which