Abstract

Metaethical relativism is the view that whether a moral claim is true depends on the standards endorsed by an individual or society. This view is attractive because it allows one to hold that moral claims can be true or false in an ordinary correspondence sense, without being committed to the view that moral claims state objective facts. But what could it mean to say that a whether a moral claim is true depends on an individual or society’s standards? How could a single claim be true or false in an ordinary sense, and yet be true for some people while false for others? This thesis defends a certain answer to this question: metaethical truth relativism. Metaethical relativists have historically endorsed a different view: content relativism, which is the view that the semantic contents of moral claims vary across contexts of use. However, semanticists working outside metaethics have recently shown that an alternative exists, namely truth relativism: the view that the truth values of moral contents vary across contexts. Metaethicists have been slow to investigate the significance of this discovery. This is surprising, because truth relativism appears to avoid some of the most influential objections to content relativist views. Thus, this development in semantics appears to offer an exciting new direction for research on relativism in metaethics. The scope of this thesis is not narrowly semantic, however. Questions in moral semantics often interconnect with questions in substantive metaethics, and the question of whether ethical thought and talk is semantically relativistic is no exception. Therefore, while the core of the this thesis focuses on moral semantics, it also contains a fair amount of substantive metaethical material, located primarily in the first and final chapters. The plan of the thesis is as follows. Chapters 1 & 2 begin with a discussion of the most historically influential argument for metaethical relativism: the argument from disagreement. Chapter 1 discusses an epistemic version of this argument, but concludes that this version provides only limited evidence for relativism. However, chapter 2 introduces a different version of the argument, with a more semantic focus, and begins to make the case that this argument provides evidence not only for metaethical relativism broadly construed, but for truth relativism in particular. The broad strokes of this argument are that there can be moral disagreements which are faultless and furthermore that only truth relativism can vindicate the sense that these are genuine disagreements, rather than mere differences of opinion. Chapter 2 presents empirical evidence for the claim that putative moral disagreements can be faultless. Chapters 3 and 4 then take a deep dive into the topic of disagreement. Chapter 3 develops a positive account of disagreement which is available only to truth relativists. And chapter 4 advances detailed arguments against contextualist accounts of disagreement. Chapters 3 and 4 together thus defend in detail the claim that truth relativism can, while content relativism cannot, account for the sense that there is genuine disagreement in the relevant cases. Chapters 2 through 4, therefore, form a single long argument for truth relativism. They show that there is a compelling argument for relativism broadly construed, and that deep analysis of the issues surrounding this argument favour truth relativism over content relativism. Chapter 5 zooms back out to the broader metaethical landscape, discussing two remaining objections to relativism. The first objection is that relativism has objectionably subjectivistic implications, and the second is that moral standards cannot helpfully be understood as determined by societies. In the course of responding to these objections, natural opportunities to flesh out the substantive metaethical commitments of the theory will arise. And this will set us up to conclude with a brief comparison of truth relativism with some of the other main options in the space of substantive metaethical theory.