3. Representation by symbols.
How is it possible that by perceiving one thing we can become aware of another thing which is evidently in no way present in the first one?
The first answer one feels tempted to give to this question is something like this: In order to understand Expression, one might say, it is sufficient to point to the simple fact of representation, i.e. a sort of correspondence between two things which we establish arbitrarily by agreeing that the one shall stand for the other, shall replace it in some given context, serve as a sign or symbol for the other, or, in short, signify it.
As for a playing child a piece of wood may mean a ship, or as for a general engaged in battle a couple of strokes on his map may represent a marching army — in a similar way our words and all our signs for words are symbols which, partly by arbitrary agreement and partly by accidental usage, stand for the things cf which they are symbols. Is it not natural to suppose that in the same way our sentences or propositions stand for the facts which they express?
A child, when learning to speak, has to be taught this prëestablished correspondence between the words and the world: this seems to be everything that is required to enable him to use the symbolism which is called his native language. He becomes able to express his thoughts and his expression can be understood because both he and those to whom he is speaking know by heart which particular thing is represented by each particular symbol. In this way the possibility of representing things by signs appears to account for the possibility of language, and nothing else seems to be needed to explain the nature of expression. But a little closer examination of the matter will easily convince us that this account is far from being satisfactory. It does not help us to understand that particular property without which a symbolism cannot be a language capable of really "expressing" anything.
4. Expression as contrasted with representation.
If we want to study a language we shall certainly begin by learning its vocabulary, i.e. the signification of its words. That is necessary, but not sufficient. We must study its grammar also. But do we not learn the grammar in exactly the same way as the vocabulary, by being taught what
