On Certainty is the best known of several published collections of material Wittgenstein wrote after the Investigations. The topics it addresses are related to some discussed in the Investigations but the closest explicit ties are to G.E. Moore’s defenses of common-sense certainty in “A Defense of Common Sense” and “Proof of an External World.”
This material is in a relatively raw state; some of it is from the sort of pocket notebooks in which Wittgenstein first recorded his thoughts. You will find him experimenting with different ways of saying what he wants to, and there will be less variation in topics throughout these texts than you have seen in the Investigations. That means that topical divisions tend to be very arbitrary. I’ve listed some below in case it makes reading easier, but the only clear divisions are those between material derived from different sources. Such breaks appear in these assignments after §65 and after §192 (when we skip to the end of the book to look at the last two days of notebook entries); the editors’ preface gives a brief account of the different sources.
Assignment for Tues. 4/24
§§1-23 (pp. 2-5): “I know”
§§24-50 (pp. 5-8): mistakes
§§50-65 (pp. 9-10): logical propositions and language games
§§66-79 (pp. 10-12): mistakes and “mental disturbance”
§§80-92 (pp. 12-14): unshakeable conviction
Assignment for Thurs. 4/26
§§93-108 (pp. 14-17): the river’s bed
§§109-136 (pp. 17-20): testing and doubt
§§137-163 (pp. 20-24): learning and inquiry
§§164-192 (pp. 24-27): groundless belief
§§654-676 (pp. 86-90): possibility of mistakes