This idea is fleshed out by the concept of ostensive definition. We can learn words by ostension with question-and-answer sequences such as "what is this?"—"this is a chair," or "what is this color?"—"this is blue." These ostensive definitions assume, however, that there is already a place in language prepared for these words. Our linguistic apparatus is functioning, but we have blank spaces that need to be filled in. We do not yet know the word for those wooden objects people sit on, or for the color of the sky, but we do know what objects and colors are and we know how to talk about them in sentences. Ostensive definition does not teach us language from scratch, but simply helps us fill in ready-formed sentences such as "the sky is x." This is not to discredit ostensive definition—clearly, it can be a very instructive tool—but only to say that the name-thing relationship is not the fundamental relationship of language. I may be given ostensive definitions of everything in my immediate environment, but this only helps because I already know how these names can be used.
Wittgenstein is not concerned with how we learn language or raising the difficult question of what we must learn prior to ostensive definition. Rather, he is challenging the notion that language connects with the world perfectly. He is challenging the notion that a word or a sentence primarily relates to the thing or fact in the world that it corresponds to. His investigation shows us that while we can often say that a word names a thing, we can only do this because a word is already related to other words, and because we already have an understanding of grammatical structure. We are already familiar with the particular language-game we are playing with this word and have an implicit understanding of the rules that accompany this language-game. Wittgetnstein foresees the danger of identifying a relationship between language and the world and then trying to isolate this relationship as if it alone were constitutive of language. There is nothing wrong, in itself, with saying that words name things, but there is a danger that we might then ignore the surrounding environment that makes the connection between words and things possible.
The discussion of meaning, and the relationship between language and the world culminates with Wittgenstein's important remark in section 43 that "the meaning of a word is its use in the language." Wittgenstein is not giving us a theory of language relating meaning to use that replaces the Augustinian picture of language. Rather, he is deflating the investigation prompted by the Augustinian picture to discover the mysterious connection between words and the things they name. If we think that language essentially consists of words that name things, we then have to explain how the connection between language and the world is established. We are liable to develop theories of meaning based on the mental state of the speaker, or the logical structure of reality. Wittgenstein's conclusion in section 43, then, is an insistence that we will not find the secret of "meaning" by investigating logic or psychology. The key is not to discover how language connects with reality, but to realize that questioning how language connects with reality is prompted by a distorted picture of what language is.
The discussion of sections 44–66 focuses on the problems of logical analysis and logical atomism. Wittgenstein criticizes not only Frege and Russell, but also Wittgenstein's own early work in the Tractatus. A driving impetus of early analytic philosophy was the notion that logical analysis could uncover the underlying structure of language and reality. Analysis relies on the assumption that language and reality can be broken down into smaller and simpler parts, and that there must be a bedrock of utterly simple objects that can be named but not defined or described (since that would suggest they were analyzable). Russell famously remarked that the only true proper names are "this" and "that," because they cannot be further analyzed or broken up.