Some scientific propositions are so well established that they are no longer debated by the relevant scientific community, such as the fact that greenhouse gas emissions are altering the Earth's climate. In many cases, such scientifically settled issues are nonetheless rejected by segments of the public. U.S. surveys have repeatedly shown that the rejection of scientific evidence across a broad range of domains is preferentially associated with rightwing or libertarian worldviews, with little evidence for rejection of scientific evidence by people on the political left. We report two preregistered representative surveys (each N > 1000) that (1) sought to explain this apparent political asymmetry and (2) continued the search for the rejection of scientific evidence on the political left. To address the first question, we focused on Merton's classic analysis of the norms of science, such as communism and universalism, which continue to be internalized by the scientific community but which are not readily reconciled with conservative values. Both studies show that people's political worldviews are associated with their attitudes towards those scientific norms, and that those attitudes predict people's acceptance of vaccinations and climate science. The norms of science may thus be in latent conflict with the worldviews of a substantial segment of the public. To address the second question, we examined people's views on the role of inheritance in determining people's intelligence, given that the belief in the power of learning and environmental factors to shape human development is a guiding principle of leftwing thought. We find no association between core measures of political worldviews and people's view of heritability of intelligence, although two subordinate constructs, nationalism and social dominance orientation, were associated with belief in heritability.