It is in defining goodness in terms of some natural property – in this case, pleasure – that makes it an ethical naturalist theory. And then, according to Moore, deriving the normative claim that we ought pursue pleasure commits the naturalistic fallacy. — Michael
Moore's view is this:
"In applying this view, Moore gave it the form of what today is called “indirect” or “two-level” (Hare 1981) consequentialism. In deciding how to act, we should not try to assess individual acts for their specific consequences; instead, we should follow certain general moral rules, such as “Do not kill” and “Keep promises,” which are such that adhering to them will most promote the good through time. This policy will sometimes lead us not to do the act with the best individual outcome, but given our general propensity to error the policy’s consequences will be better in the long run than trying to assess acts one by one; however well-meaning, the latter attempt will be counterproductive (1903: 149–70/1993: 198–219. This indirect consequentialism had again been defended earlier, by Sidgwick and John Stuart Mill, but Moore gave it a very conservative form, urging adherence to the rules even in the face of apparently compelling evidence that breaking them now would be optimific. Principia Ethica made the surprising claim that the relevant rules will be the same given any commonly accepted theory of the good, for example, given either hedonism or Moore’s own ideal theory (1903: 158/1993: 207). This claim of extensional equivalence for different consequentialist views was not new; T.H. Green, F.H. Bradley, and McTaggart had all suggested that hedonism and ideal consequentialism have similar practical implications. But Moore was surely expressing the more plausible view when in Ethics he doubted that pleasure and ideal values always go together (1912: 234–39/1947: 144–47/1965: 100–02), and even when he accepted the equivalence claim he remained intensely interested in what he called “the primary ethical question of what is good in itself” (1903: 158, 26, 77/1993: 207, 78, 128). Like Green, Bradley, and McTaggart, he thought the central philosophical question is what explains why good things are good, i.e., which of their properties make them good. That was the subject of his most brilliant piece of ethical writing, Chapter 6 of Principia Ethica on “The Ideal.”
So he is a consequentialist, just making clear though that he doesn't what to take a very simple reducible definition of "the good" to be immediate pleasure like Bentham. He then goes on to explain. "The Ideal" to mean that which should be promoted (i.e. "the good ") is a number of things, and since it's not monistic, he somehow avoids being naturalistic. It's explained as:
"One of this chapter’s larger aims was to defend value-pluralism, the view that there are many ultimate goods. Moore thought one bar to this view is the naturalistic fallacy. He assumed, plausibly, that philosophers who treat goodness as identical to some natural property will usually make this a simple property, such as just pleasure or just evolutionary fitness, rather than a disjunctive property such as pleasure-or-evolutionary-fitness-or-knowledge. But then any naturalist view pushes us toward value-monism, or toward the view that only one kind of state is good (1903: 20; 1993: 72). Once we reject naturalism, however, we can see what Moore thought is self-evident: that there are irreducibly many goods. Another bar to value-pluralism is excessive demands for unity or system in ethics. Sidgwick had used such demands to argue that only pleasure can be good, since no theory with a plurality of ultimate values can justify a determinate scheme for weighing them against each other (1907: 406). But Moore, agreeing here with Rashdall, Ross, and others, said that “to search for ‘unity’ and ‘system,’ at the expense of truth, is not, I take it, the proper business of philosophy” (1903: 222/1993: 270). If intuition reveals a plurality of ultimate goods, an adequate theory must recognize that plurality."
My responses are this:
1. I think this gives short shrift to Mill. Mill's reference to happiness as being the objective of "the good" didn't at all suggest it was a reducible concept, but he was clear that happiness arose from a variety of factors and it was a holistic state that could not be achieved from just finding physical pleasure. I don't follow why Mill is a naturalist but Moore not.
2. Go back and re-respond to this
here and explain why my response doesn't now apply, particularly to (b). Just plug in Moore's definition of morality into (b), and that offers a reason why it matters what you think is moral for a non-naturalist.