 “Names of philosophical positions,” wrote W. V. O. Quine, “are a necessary evil” (1995: 251). This is certainly the case with the term “empiricism”: while it is difficult simply to abandon it, it can be misleading. Among historians of early modern philosophy, for instance, the traditional distinction between empiricists and rationalists has fallen out of favour, on the grounds that there are few thinkers who can be clearly assigned to either category (Norton 1981; Loeb 1981: 25–75). The problem here, however, is not the category of empiricism, but its use as a “pigeon-hole” into which one tries to place individual thinkers. Empiricism need not be a global doctrine: a thinker may be an empiricist in one domain but not in another. It is possible, for instance, to be an empiricist about knowledge of the natural world, but a rationalist with regard to a particular area of mathematics (Markie 2015: sect. 1.2). So it is not surprising that individual thinkers are hard to categorize. But empiricism is also an umbrella term: it covers a variety of views regarding knowledge. Even with regard to the one domain, a thinker may be an empiricist in one sense, but not in another. So if we are to use the category, we need to distinguish the different forms empiricism can take. 