[M]oral nonnaturalism faces the challenge of explaining the normativity of morality just as much as does moral naturalism. If normativity needs to be explained, it is not explained by giving up on naturalistic ways of explaining it. Antireductionist forms of nonnaturalism that view moral properties as sui generis face an especially difficult problem, for they appear simply to postulate normativity. It is unclear how they could explain it.
David Copp, Morality in a Natural World: Selected Essays in Metaethics, Cambridge, 2007, p. 282
It is an ironic fact that the felt qualities of conscious experience, perhaps the only things that ultimately matter to us, are often relegated in the rest of philosophy to the status of ‘secondary qualities,’ in the shadowy zone between the real and the unreal, or even jettisoned outright as artifacts of confused minds.
Jaegwon Kim, Physicalism, or Something Near Enough, Princeton, 2005, p. 12
[T]he much-vaunted analogy with natural kinds is of little help, and actually stands in the way of seeing what the mechanism might be. For our beliefs concerning natural kinds are not in general independent of perceptual experience. If we were to learn that most of our perceptual experience was non-veridical, then little would be left of our knowledge of natural kinds. The brain-in-the-vat is at a severe epistemic disadvantage in coming to any form of scientific knowledge; and if there really were an analogy between our understanding of scientific and of ethical terms, then one would expect him to be at an equal disadvantage in the effort to acquire moral wisdom. It is for this reason that the continuity in moral and scientific inquiry so much stressed by writers such as Boyd and Railton appears entirely misplaced. A much better analogy is with our understanding of mathematical terms, for which the idea of a hookup with the real world is far less plausible.
Kit Fine, ‘The Varieties of Necessity’, in Modality and Tense: Philosophical Papers, Oxford, 2005, p. 258
Naturalism and Non-Cognitivism are both […] close to Nihilism. Normativity is either an illusion, or involves irreducibly normative facts.
Derek Parfit, On What Matters, chap. 24, sect. 82
Prichard seems to have thought […] that the normativity of morality cannot be explained at all. But that does not follow. Even if there is no instrumental explanation of its normativity, there may be an explanation of some other sort. It would truly be unsatisfactory if there was no explanation at all. It would be a bad blow to philosophy to find there are inexplicable facts.
John Broome, ‘Reply to Southwood, Kearns and Star, and Cullity’, Ethics, vol. 119, no. 1 (October, 2008), p. 98
I think that while some parts of natural human morality may rest on illusion, hedonically grounded practical reasons, and at least those parts of morality that rest on them, very likely have some objective normative standing.
Leonard Katz, ‘Hedonic Reasons as Ultimately Justifying and the Relevance of Neuroscience’, in Walter Sinnott-Armstrong (ed.), Moral Psychology, Vol. 3: The Neuroscience of Morality: Emotion, Brain Disorders, and Development, Cambridge, Massachusetts, 2008, p. 409
There is no need to import superstition. We can begin with a mechanistic view of the world, one in which bits of energy and matter interact in various ways perhaps according to certain deterministic or probabilistic laws of causation; and in which people’s lives are determined by the interplay of their own desires, goals, commitments, urges, and impulses with those of other people, steered by different beliefs about the world, of varying degrees of falsehood and veracity, all within the limits imposed by nature; but a world that exhibits no transcendent purpose or meaning or design in any of its parts—no purpose, that is, outside the purely continent (and usually quite powerless) wills of individual people and animals. Nevertheless, surely it would be blindness to fail to see, at the very least, that some things in this purposeless world are objectively bad; that these things ought not to arise; that we are obliged by their very badness to prevent them from arising; and that certainly the experience of suffering in its many forms has this very property of objective badness that I have been describing, even if nothing else has it. It seems to me stranger to deny this than to affirm it.
Jeremy Mayerfeld, Suffering and Moral Responsibility, New York, 1999, p. 113
Normative concepts form a fundamental category-like, say, temporal or logical concepts. We should not expect to explain time, or logic, in non-temporal or non-logical terms. Similarly, normative truths are of a distinctive kind, which we should not expect to be like ordinary, empirical truths. Nor should we expect our knowledge of such truths, if we have ay, to be like our knowledge of the world around us.
Derek Parfit, ‘Reasons and Motivation’, Proceedings of the Aristotelian Society, supp. vol. 71 (1997), p. 121