Scientists across the life sciences routinely appeal to notions of "innate" or "genetic" traits to explain developmental phenomena, and the idea of "innate" differences among people has figured prominently in some explanations of observed social inequality. This dissertation is an analysis of these concepts, which proceeds in two parts. Part I explores various philosophical issues related to the use of innateness as an explanatory concept, while Part II examines controversial claims that genetic differences among racial groups account for observed social inequality. I argue throughout that much disagreement about innateness arises from innocuous differences in explanatory goals and interests among different scientific research programs. Nevertheless, some proponents of genetic racial differences rely on understandings of "genetic" traits that conflict with the moral commitments of a just society.

Part I begins with arguments for a contextual and pragmatic approach to scientific explanation: in order for an explanation to be a good one, it must cite causes that are relevant to our interests in the explanatory context. I then apply this framework to biology and psychology, showing how different contexts call for different interpretations of innateness. I conclude Part I by responding to arguments that aim to establish a single meaning for "innate"/"genetic" across all explanatory contexts.

Part II examines the use of "innate" and "genetic" concepts in developmental biology and population genetics, and applies the lessons of this examination to debates about alleged racial differences in genes for intelligence. I show that "hereditarians," who argue for innate racial differences, employ an explanatory framework that abstracts away from substantial complexity in developmental interactions between genes and environments. While this framework is adequate for certain purposes, it is poorly suited to designing interventions capable of eliminating racial IQ differences and attendant social inequality. I propose an alternative, mechanistic framework that promotes understanding of developmental complexity and design of effective interventions. I argue that a full commitment to racial equality demands that we adopt this latter framework, and to the extent that hereditarians resist doing so, their work exhibits some racist tendencies.