Philippa Foot, answered from the texts and cited to the page.
Moral realism, as I understand it, is best approached by separating it carefully from a position it is often confused with: cognitivism. A cognitivist theory of ethics holds that moral judgements are about the world in the same way that other assertions are — that when I say "cruelty is wrong," I am making a claim that has a truth-value, not merely expressing an attitude or issuing a prescription.1
Realism, in the stronger sense that Michael Dummett meant by it, goes further: it refuses to let the possession of truth or falsity by a particular ethical proposition stand or fall by our capacity, or lack of capacity, for assigning truth or falsity to it.2 Those who say that where the solution of some ethical conflict is beyond our capacities there will nevertheless be a solution — perhaps known to God — are realists; those who deny it are anti-realists with respect to that class of propositions.3
I am a cognitivist. Whether I am a realist in Dummett's sense is a harder question, and I have been content to leave it somewhat open. What matters for my purposes is the cognitivist claim, because that is what the subjectivist tradition — Stevenson, Ayer, Hare, and their sophisticated successors — denies. The grounding of a moral argument is ultimately in facts about human life, and a moral evaluation does not stand over against a statement of fact as something of an entirely different logical kind.4
Nobody would take it as other than a plain matter of fact that there is something wrong with the hearing of a gull that cannot distinguish the cry of its own chick; similarly, there are objective, factual evaluations of human sight, hearing, memory, and concentration based on the life form of our species.5 The question I press is why it should seem monstrous to extend that same logical structure to the evaluation of the human will.6
The natural-goodness framework, worked out in my book of that name, supplies the answer. Aristotelian necessities — what is necessary because and insofar as good hangs on it — govern plants, animals, and human beings alike.7 It is necessary for wolves to hunt in packs, for lionesses to teach their cubs to kill; these necessities are determined by what a species needs, its natural habitat, and the ways of making out that are in its repertoire.8
Human defects and excellences are similarly related to what human beings are. Kant was right that moral goodness is goodness of the will, but wrong to think that an abstract idea of practical reason applicable to rational beings as such could take us all the way to anything like our own moral code — the evaluation of human action depends also on essential features of specifically human life.9
So moral realism, for me, is not a metaphysical thesis about mind-independent moral facts floating free of natural facts. It is the claim that moral evaluation belongs to the same logical category as the evaluation of sight in a gull or the hunting behavior of a wolf — grounded in the life form of the species, objective in the sense that it is not a matter of attitude or preference, and capable of being true or false in exactly the way that any other evaluation of a living thing can be true or false.
A cognitivist theory of ethics says that moral judgements are about the world as are other kinds of assertions—with, no doubt, many significant variations.Moral Dilemmas and Other Topics, pp. 34–35
A realist theory of ethics would be one that refused to let the possession of truth or falsity by a particular ethical proposition stand or fall by our capacity or lack of capacity for assigning truth or falsity to it.Moral Dilemmas and Other Topics, pp. 34–35
Those who say that where the solution of some ethical conflicts is beyond our capacities there will nevertheless a solution which is perhaps known to God are realists: those who deny it are anti-realists as regards the class of propositions in which moral judgements are asserted.Moral Dilemmas and Other Topics, pp. 34–35
The thesis of this chapter is that the grounding of a moral argument is ultimately in facts about human life... a moral evaluation does not stand over against the statement of a matter of fact, but rather has to do with facts about a particular subject matter.Natural Goodness, p. 17
Nobody would, I think, take it as other than a plain matter of fact that there is something wrong with the hearing of a gull that cannot distinguish the cry of its own chick, as with the sight of an owl that cannot see in the dark.Natural Goodness, p. 17
Why, then, does it seem so monstrous a suggestion that the evaluation of the human will should be determined by facts about the nature of human beings and the life of our own species?Natural Goodness, p. 17
Anscombe is pointing here to what she has elsewhere called an 'Aristotelian necessity': that which is necessary because and in so far as good hangs on it.Moral Dilemmas and Other Topics, p. 118
We invoke the same idea when we say that it is necessary for plants to have water, for birds to build nests, for wolves to hunt in packs, and for lionesses to teach their cubs to kill.Moral Dilemmas and Other Topics, p. 118
Kant was perfectly right in saying that moral goodness was goodness of the will... He seems to have gone wrong, however, in thinking that an abstract idea of practical reason applicable to rational beings as such could take us all the way to anything like our own moral code. For the evaluation of human action depends also on essential features of specifically human life.Moral Dilemmas and Other Topics, p. 118