1 What is Relativism ?

Few philosophers have been tempted to be relativists about absolutely everything—although, we are told, there have been some notable exceptions (Protagoras). Many philosophers, however, have been tempted to be relativists about specific domains of discourse, especially about those domains that have a normative character. Gilbert Harman, for example, has defended a relativistic view of morality, Richard Rorty a relativistic view of epistemic justification, and Crispin Wright a relativistic view of judgments of taste.1 But what exactly is it to be a relativist about a given domain of discourse? The term ‘‘relativism’’ has, of course, been used in a bewildering variety of senses and it is not my aim to discuss each and every one of those senses here. Rather, what interests me is the notion that is characterized by the following core idea: the relativist about a given domain, D, purports to have discovered that the truths of D involve an unexpected relation to a parameter. This idea lies at the heart of the most important and successful relativistic theses ever proposed. Thus, Galileo discovered that the truths about motion are unexpectedly relational in that the motion of an object is always relative to a variable frame of reference. And Einstein discovered that the truths about mass are unexpectedly relational in that the mass of an object is always relative to a variable frame of reference. In this paper, I will develop a model for how such discoveries should be understood. And I will then consider to what extent that model gives us a purchase on the sorts of relativistic theses—about morality, for example, or epistemic justification—which have most interested philosophers.