Another argument about which big fuss is being made of in metaethics is Mackie's 'Argument from Relativity' (in his Ethics: Inventing Right and Wrong, 1977).
(AR1) It "has as its premiss the well-known variation in moral codes from one society to another and from one period to another, and [...] the differences in moral beliefs between different groups and classes within a complex community" (Mackie 1977, 36).
(AR2) The "radical differences between [those] moral judgements", he continues arguing, "make it difficult to treat those judgements as apprehensions of objective truths" (ibid.).
(ARC) Hence, he concludes "there are no objective issues" (ibid.) corresponding to moral judgements. (Instead, he explains, moral judgements just "reflect people's adherences to different ways of life" (ibid.).)
Mackie's example is monogamy. The different opinions about the matter of monogamy/polygamy is better explained, he suggests, by the view that "people approve of monogamy because they participate in a monogamous way of life" than by the view that "they participate in a monogamous way of life because they approve of monogamy".
It may be worth remarking that, surely, even massive disagreement among ordinary people, or even academics, does not enable the conclusion that there is no fact of the matter. Such massive disagreement consists, for example, about the question what exactly Mackie actually had in mind with the Argument from Queerness. Are we to conclude that he had nothing in mind? Or take the question whether the earth is flat or round (15th century): Should it have been concluded that the world has no shape at all?
Furthermore, even if perhaps monogamy is an issue about which there is much diversity, only if each and every one of the moral issue we know of were to lack a fact of the matter would Moral Realism be seriously threatened. Yet it seems that about many moral issues there is large consensus; consider the tantalizing of innocent beings; or lying, theft and murder. If there is a fact about the matter in these cases, Mackie's argument will not threaten Moral Realism. Did Mackie really argue that moral diversity is exceptionless? Or how is the argument to proceed if it is not?
Again, the Swabian defence of OMR gets around the consideration of partially vague and speculative issues. It treats the matter dead-on, by offering examples of (dis-)value and 'moral
'oughts' about whose existence there apparently can be no diversity of opinions. A being suffers: Is there any radical doubt that this is dis-valuable (all things being equal)?
Hardly so. A child can easily be saved by Mrs. Jones from a burning house: Is there any radical disagreement that Mrs. Jones should save him, all things being equal? Hardly so. The Argument
from Relativity will start getting really interesting only as soon as we have difficulties of finding clear cases; so let us start by finding clear cases, and turn to the Argument from
Relativity only after we failed.