We may well be witnessing a decisive event in the history of knowledge as diversity is becoming one of the premier values of late modern societies. We seek to preserve and foster biodiversity, neurodiversity, racial diversity, ethnic diversity, gender diversity, linguistic diversity, cultural diversity, and perspectival diversity. Perspectival diversity has become the passage point through which other forms of diversity must pass to become epistemically consequential. This article examines how two of its varieties, viewpoint diversity and educational diversity, have come (...) to transform the moral economy of science. Both aim at multiplying perspectives on a given subject, but their political subtexts differ markedly. The valorization of educational diversity followed a US Supreme Court decision in 1978 that enabled universities to advance social justice, if they justified race-conscious admissions in terms of the pedagogic benefits of a more diverse student body for all. By contrast, the proponents of viewpoint diversity aim at the reform of scientific knowledge production and distribution rather than the reallocation of status and power among different social groups. We examine the political epistemology of viewpoint diversity by analyzing a controversy between social psychologists who, amid the American culture wars of the 2010s, debated how to rein in their political biases in a scientific field supposedly lacking political diversity. Out of this scientific controversy grew Heterodox Academy, an activist organization promoting viewpoint diversity in higher education. By relating and comparing viewpoint and educational diversity, we clarify what is at stake epistemically in the US-centric moral economy of diversity. (shrink)