This paper relates discussions of scientific ontology to debates about the value-ladenness of science. First, I distinguish three types of pluralism about kinds and argue that none of them threatens realism. Then I argue that pluralist realism about kinds has implications for the debate about the role of non-epistemic values in science. Pluralist realists hold that there are more kinds than we will ever have the resources to focus on. Hence, while epistemic values are responsible for identifying kinds, non-epistemic values can play a role in deciding which ones to focus on in scientific theory and practice.

Some philosophers understand natural kinds to be the categories which are constraints on enquiry. In order to elaborate the metaphysics appropriate to such an account, I consider the complicated history of scurvy, citrus, and vitamin C. It may be tempting to understand these categories in a shallow way (as mere property clusters) or in a deep way (as fundamental properties). Neither approach is adequate, and the case instead calls for middle-range ontology: starting from categories which we identify in the world and elaborating their structure, but not pretending to jump ahead to a complete story about fundamental being.

The 1950/51 UNESCO statements on race were opposed by a group of scientists who rejected the post-WWII scientific consensus that the human species does not divide neatly into races. Both sides of this dispute had explicit political purposes. The dispute turned on a difference between two models of the human species. Many accounts make model evaluation depend on the user's purposes. Applied to this case, such views render political the empirical question about whether races exist. This essay argues that there are empirical constraints on model use that are independent of and constrain the user's purposes.

Is race real? If so, what exactly is it? These questions have captivated both philosophers and social scientists alike. Participants in these debates frequently appeal to race’s role in explaining various social phenomena, though they rarely engage with empirical social science. In this paper, we will argue that the kinds of empirical success that race enjoys in the social sciences do not support the claim that races, as used in social science research, are accurately represented. In fact, we shall argue that race's empirical success appears to be less than that of the phlogiston theory.