4.0141 In the fact that there is a general rule by which the musician is able to read the symphony out of the score, and that there is a rule by which one could reconstruct the symphony from the line on a gramophone record and from this again – by means of the first rule – construct the score, herein lies the internal similarity between these things which at first sight seem to be entirely different. And the rule is the law of projection which projects the symphony into the language of the musical score. It is the rule of translation of this language into the language of the gramophone record.

This is all Wittgenstein’s translation. See Letters to Ogden p. 26. Cf. 3.11.

I have wondered whether the last sentence could possibly be a joke. What could the rule be by which one reads music from a score? Of course people do this, just as we can read aloud from a printed script. But I'm not sure what there is apart from the printed word and the sounds we make. There is something, seemingly, but what is hard to say. Rules are not easy to understand, and nothing here seems to help very much.