This dissertation investigates the plausibility of metaethical relativism, or more specifically, what I call “moral truth-value relativism”: the idea that the truth of a moral statement or belief depends on who utters or has it, or who assesses it. According to the most prevalent variants of this view in philosophical literature – “standard relativism” – the truth-values are relative to people’s moralities, often understood as some subset of their affective or desirelike attitudes. Standard relativism has two main contenders: absolutism – (...) the view that the truth-values of moral statements and beliefs do not vary in that way – and non-cognitivism – the view that moral judgements do not have truth-values, since they express affective or desire-like attitudes rather than beliefs. Almost the entire dissertation concerns the plausibility of standard relativism in contrast to absolutism. Part 1 examines first the two main arguments for standard relativism: that it accounts for the connection between moral judgements and motivation (chapter 2), and for the prevalence of diversity of moral opinion (chapter 3). Then the most common objection is considered: that it is inconsistent with the existence of genuine moral disagreements (chapter 4). I argue that these arguments are inconclusive. Both relativism and absolutism can account for the features discussed. Part 2 focuses on the fact that different people have different strongly held intuitions about the relative or absolute nature of morality. I argue that given a common methodological approach in philosophy and metaethics, which takes such intuitions as evidence of correct analyses, this difference in intuitions suggests that neither a relativist nor absolutist analysis can be correct for everyone’s moral judgements. I argue that this result holds both given semantic internalism (chapter 6) and given semantic externalism (chapter 7). To get one single analysis of everyone’s moral judgements we would have to abandon the intuitionbased methodology. In chapter 8, however, I argue that we can maintain this methodology if we accept analysis pluralism, the view that different analyses hold for different people’s moral judgements. (shrink)