"[G.E. Moore] was in those days beautiful and slim, with a look almost of inspiration, and with an intellect as deeply passionate as Spinoza's. He had a kind of exquisite purity."--Ernest Nagel quoting Russell on Moore.
"But Professor Moore, why do you spend so much time refuting that doctrine; surely [this emphatic use of "surely" he had learned from Moore] no one holds it. To which Moore replied, in a rising crescendo of rhetorical questions: "No one holds it? No one holds it? No one holds it? But Montague holds it-don't you Montague?" Professor Montague rolled his eyes and shook his head affirmatively."--Morton White recalling a seminar with Moore.
By treating Boole's contributions as merely mathematical and requiring a conventional step (the coding of predicates/sentences), Michael Dummett (and here) convinced himself and others that analytical philosophy has its original roots in Frege's more powerful logic and, thus, what we may call the philosophy of mathematics (for an alternative view). By contrast, at the 1959 memorial symposium on G.E. Moore at Columbia University (published in 1960 in JPhil), Ernest Nagel, who I claim (and here; recall Jeff's point) created our shared picture of analytical philosophy, has no doubt that "Moore did help to bring about a revolution, if not in philosophy, at any rate in the philosophical climate, and at the same time a marked heightening in standards of philosophical workmanship." (812; recall Catarina on Moore) Moore and his revolution stand for the "passionate devotion to the pursuit of intellectual clarity." (811) His clarity was reflected in his writing, of course, and also bequeathed to the discipline through his charismatic teaching style.
Before I turn to Nagel's understanding of the sources and costs associated with Moore's legacy, I should emphasize that Nagel is careful to disassociate Moore from the (then) "current revolts against the traditional conception of philosophy as an inquiry into the most general features of the entire scheme of things." (811) In fact, by quoting from Some Main Problems of Philosophy, Nagel reminds his audience of Moore's vision that one of the tasks of philosophy is to present "a general description of the whole of the Universe. " Even so, Moore's conception of philosophical truth meant, in practice, that he was extremely wary of systematical elaboration. (812) Rather than seeing in Moore an anti-metaphysician (cf. Ayer), he is, thus, better thought of as re-opening the door to a very deflationary Realism. (See also Alice Ambrose's very interesting contribution to the Memorial Session.) Fair enough.
Connected to Nagel's criticism that Moore was too narrow in "taking philosophical discussion as the subject-matter of philosophy," (816) is a feature of Moore's persona that was, alas, widely emulated in the discipline. White recounts with evident relish that that Moore happily owned up to ignorance in the history of philosophy (see the famous anecdote about Whewell (808-9)). In White's hands Moore stands for the justified rejection of the once "accepted view...that philosophy required great learning in the sciences and history, or technical expertise in logic, or a professional fondness for wisdom." (806) But it makes more sense to understand Moore as creating a facade -- my term not White's -- of learned ignorance; as Nagel puts it, students were taken in by Moore's "seemingly simple and naive manner of discussion." (813) Even though some technical competence in the sciences is encouraged in some circles, to this day if professional analytical philosophers tell you that you are "widely read" or "learned," you can rest assured they do not mean it as a philosophical compliment.
Of course, Moore was not ignorant at all. As Nagel reminds his reader:
Moore was trained in the classics, and he imported into the discussion of philosophical problems the meticulously careful habit of construing the possible meanings of a statement that a sound classical scholar exhibits in interpreting obscure texts. This is not the only instance in thie history of philosophy in which the adoption of habits and techniques of analysis first developed in some other discipline has resulted in noteworthy reorientations in philosophical perspective. (813)
That is to say, by our standards, Moore was extremely well read. Not unlike Descartes or Spinoza, Moore suppressed bookish knowledge from his public utterances. Of course, that's not the main point of the passage that I just quoted. While Nagel sadly ignores the significance of Sidgwick's teaching (and makes no mention of the Cambridge Apostles), Nagel puts his finger on one of the major roots of analytical philosophy: it has its origin in an undergraduate's perspective on philological practice.