Pp. 24-25 (“Let us introduce ...”-“... to exact rules.”): criteria and symptoms. One way to see the significance of the distinction between criteria and symptoms is to ask yourself how another philosopher might describe it. For making a distinction like this is somewhat uncharacteristic for Wittgenstein since it is a standard sort of philosophical move. Although making it might blunt his challenge to ordinary philosophical activity, it does provide him a useful way into the thinking that lies behind other discussions of, for example, the difference between philosophical and scientific problems. But, although Wittgenstein applies the distinction in this way elsewhere, here his aim is to make a point about the distinction itself.

Pp. 25-29 (“This is very one-sided ...”-“... the South Pole.”): rules and philosophical puzzlement. Wittgenstein’s comments on strict rules in this section can be compared with the earlier discussion of our craving for generality. But the critique of philosophy is carried more deeply here—think about what Wittgenstein means when he describes philosophy as “a fight against the fascination which forms of expression exert upon us.” And ask yourself what the role “ideal languages” might play in this fight.

Both Russell and Wittgenstein agreed with Frege that language could mislead us about the logical form of sentences and that some form of clarification in this regard could solve philosophical puzzles. Russell took the Tractatus to aim at the description of an ideal, “logically perfect,” language that would avoid misleading us. Wittgenstein’s later work is less likely to suggest such an aim, but he continues to describe artificial languages or language games—e.g., using a color chip to find a red flower—and one of his concerns in this section is to explain the significance of such descriptions.

Pp. 43-45 (“Let us sum up ...”-“... their final places.”): a summary, the metaphor of the library. This selection has a bit more about Wittgenstein’s view of philosophy. Think about his discussion of the library in connection earlier remarks about what philosophy should aim for.

Pp. 55-57 (“We use the phrase ...”-“... a great deal.)”): the metaphysician’s craving. Compare the craving described on p. 55 to the attitude towards maps described on p. 57. The intervening discussion is an indication of how Wittgenstein would now make the point he made in the Tractatus by saying that the only necessity is logical necessity.