Previously I took some notes on Moore.I will fill in the notes on the preceding four chapters later. Now it seems appropriate to sum up things I gained from reading those four chapters and two of Moore's works: Principia Ethica and "Proof of an External World".
1. Moore's common sense position and its connection to the concept of philosophical analysis: according to Prof.Soames, Moore's defense of common sense plays a crucial role in his methodology of philosophical analysis. Moore posited that our pre-philosophical common sense about material things and people around us is epistemologically unquestionable, and that no philosophical theorizing can claim to lay a firmer ground for certainty in our lives than common sense does. Thus Moore thought that the task of philosophical analysis is not to go against common sense and to posit thesis that dispute common sense drastically, but to accept our common sense as the starting point, and try to explain how this( although not a priori, but pre-philosophically valid)knowledge is possible. Russell partly shared this position in his epistemology and his design of logical atomism.Notice that here "common sense" was refined by Moore to denote specifically some things(most of which capable of being represented by propositions)that we know about the material things and people around us. It involves properties and relations concerning spacio-temporal presentations of those thing aforementioned, but It does not involve properties or relations concerning evaluating judgements or what Russell may call "knowledge by inference", etc.
2.The core concept of Moore's revolutionary ethics is "the undefinable nature of Good". According to Moore, no predicate except "good"is such that it can pass the open question test:"For all x, if x is D, is x good?"in the strictest sense of analyticity. For according to Moore, a subject-predicate sentence that counts as a definition of good should contain as the definition a predicate that is substitutive salva veritate with "good", but since no other, "natural",predicate can satisfy this condition, or, in another word, it can never be safely said that x is good iff x is D,Moore thought that there is just no transparent definition of "good". In Principia Ethica Moore went at length to criticize the practice of establishing equivalence between "good" and other "natural" predicates, and called it "the naturalist fallacy". This famous position is later called the non-cognitivist position of ethics. It is also worth noticing that Moore together with Hare first proposed a version of supervenience of value properties on physical properties, which was later introduced into the philosophy of mind.(cf. Jaekwon Kim, "On the Nature of Supervenience").
About Moore I'll just say so much. I will do two comebacks later: I'll fill in the notes on the four preceding chapters, and when it comes to Russell's epistemology, I'll make reference to Moore's epistemology in "Proof of an External World".