(Quotations are from Philosophical Grammar by Ludwig Wittgenstein, translated by Anthony Kenny, published 1974 by Blackwell. I’m mostly looking at Part 1 Chapter 1 section 2, found on pages 39-40 of this edition.)
“We regard understanding as the essential thing, and signs as something inessential. – But in that case, why have the signs at all? If you think it is only so as to make ourselves understood by others, then you are very likely looking on the signs as a drug which is to produce in other people the same condition as my own.”
We can say signs are “inessential” because you could use different signs to convey a similar meaning. What’s essential is that you use appropriate signs of some sort, not that you use precisely these ones.
Signs have a purpose. Like a drug, you use them to create an effect in the mind – of the person or persons you are communicating with.
“Suppose that the question is ‘what do you mean by that gesture?’ and the answer is ‘I mean you must leave’. The answer would not have been more correctly phrased: ‘I mean what I mean by the sentence ‘you must leave’.”
A gesture is a sign, and once you understand the gesture you take the meaning: you must leave. As long as you understand the gesture, you don’t need to translate the meaning into words before you know how you are expected to act.
“In attacking the formalist conception of arithmetic, Frege says more or less this: these petty explanations of the signs are idle once we understand the signs. Understanding would be something like seeing a picture from which all the rules followed, or a picture that makes them all clear. But Frege does not seem to see that such a picture would itself be another sign, or a calculus to explain the written one to us.”
Once you understand something, you see clearly how it is to be interpreted. The signs can speak directly to you, now that you have this understanding. Once again: you don’t need to translate the signs into new signs, you simply understand the original signs now that you grasp the rules.
“If I give anyone an order I feel it to be quite enough to give him signs. And if I am given an order, I should never say: ‘this is only words, and I have got to get behind the words’. And when I have asked someone something and he gives me an answer I am content – that was just what I expected – and I don’t raise the objection: ‘but that’s a mere answer.’”
Assuming the one giving the order and the one who receives it are speaking the same language, it’s enough to simply give the order. Understanding (of the language) is there, so the signs speak for themselves.
“But if you say: ‘How am I to know what he means, when I see nothing but the signs he gives?’ then I say: ‘How is he to know what he means, when he has nothing but the signs either?’
“What is spoken can only be explained in language, and so in this sense language itself cannot be explained.
“Language must speak for itself.”
So we don’t have “nothing but the signs”: what we have is signs in the context of a language. And a language speaks for itself, to those who understand it.
Wittgenstein will go on to show that there are many different ways to “understand”, and just because we use this same word to describe these different ways, it doesn’t mean that there is a single psychological process called “understanding” underlying each one. In the section of Philosophical Grammar I’ve been looking at here, Wittgenstein has been looking at some aspects of what it means to understand a language. We understand a language when we can picture the things that are communicated to us in that language. Language is “pictorial”. “The concept of language is contained in the concept of communication”, because in order to communicate one must make use of language.