The Self-Undermining Arguments from Disagreement

Arguments from disagreement against moral realism begin by calling attention to (or supposing) widespread, fundamental moral disagreement among a certain group of people (e.g., the folk, moral philosophers, idealized agents). Then, some skeptical or anti-realist-friendly conclusion is drawn. Chapter 2 proposes that arguments from disagreement share a structure that makes them vulnerable to a single, powerful objection: they self-undermine. For each formulation of the argument from disagreement, at least one of its premises casts doubt either on itself or on one of the other premises. On reflection, this shouldn’t be surprising. These arguments are intended to support very strong metaphysical or epistemological conclusions about morality (e.g., that there are no moral facts, that none of our moral beliefs are justified). They must therefore employ very strong metaphysical or epistemological premises. But, given the pervasiveness of disagreement in philosophy, especially about metaphysics and epistemology, very strong premises are virtually certain to be the subject of widespread, intractable disagreement—precisely the sort of disagreement that proponents of these arguments think undermine moral claims. Thus, these arguments undermine their own premises. If Chapter 2’s argument is sound, it provides realists with a single, unified strategy for responding to any existing or forthcoming arguments from disagreement.