Wittgenstein finished part 1 of the Philosophical Investigations in the spring of 1945. From 1946 to 1949 he worked on the philosophy of psychology almost without interruption. The present two-volume work comprises many of his writings over this period. Some of the remarks contained here were culled for part 2 of the Investigations; others were set aside and appear in the collection known as Zettel. The great majority, however,...