• The special terminology (or special meanings for familiar terminology) that Russell introduces in the selection from ch. 1 sets the stage for a discussion of idealism, in particular, Berkeley’s view that “to be is to be perceived.” Of the terms sensation, sense data, physical object, and matter, it is the second that you will run into most often. But Russell’s special sense of “matter” is employed in the statement of the argument for idealism he considers in the selection from ch. 4. In that regard, note that his definition of “matter” does not by itself imply that it is opposed to the mental. Indeed, in Russell’s terminology, Berkeley’s idealism implies that matter is mental.

• The material from ch. 4 consists of Russell’s response to the second of two arguments for idealism he considers in that chapter. Its interest for our purposes is that provides him the occasion to introduce distinctions among forms of knowledge that he develops in ch. 5.

• Russell begins ch. 5 (in ¶¶5.1-5.3) by expanding on his initial discussion of the distinction between by acquaintance and knowledge by description, which appeared at the end of chapter 4.

• Next (¶¶5.4-5.12) he surveys the varieties of knowledge by acquaintance. Much of this discussion picks up points made already in the book, though he develops some ideas further. Although brief, the account of the various forms of acquaintance suggests the outlines of Russell’s empiricism. Note especially the final form of acquaintance in ¶5.12; the suggestions of a sort of “platonism” are confirmed in later chapters of Russell’s book.

• Russell’s account of knowledge by description employs the concept of definite descriptions and his analysis of such phrases; this gets presented in ¶¶5.13-5.17.

• Russell’s most fully developed example of knowledge by description is knowledge of Bismarck. The section where this is discussed (¶¶5.18-5.22) contains several ideas that you should pay especially close attention to.

• Russell’s claim that ordinary proper names are disguised definite descriptions (¶5.17) is in keeping with his views about our knowledge of external objects, but it has been influential independently as an account of the meanings of such words. Think whether you agree with him; at the end of the semester, we will look at ideas associated with a criticism of this approach to the meaning of proper names.

• Thinking through Russell’s account of degrees of knowledge of things (¶¶5.18-5.19 and summarized in ¶5.22) is a good way of thinking yourself into his perspective on our knowledge of objects.

• The problem Russell tries to solve in ¶5.21 and his solution to it also provide valuable evidence of the way Russell thinks about knowledge and meaning. The distinctions he makes here are subtle, but coming to understand them will repay you in understanding not only Russell but also related ideas that will appear later in the course.

• The final important idea in the chapter is Russell’s “fundamental principle of analysis” (¶5.23). Begin to think about it now; the full elaboration of this picture of understanding (ch. 12) is the other key chapter in the book.