5 Why Inductive Risk Requires Values in Science Heather Douglas Introduction Although science is our most reliable source for empirical knowledge, it is also endemically uncertain, largely because of its inductive nature. Because of this uncertainty, scientists are continually faced with the judgment of whether the evidence they have on hand is sufficient to support an empirical claim. In this essay, I argue that social and ethical values are needed to help scientists make this judgment, because purely internal standards (such as epistemic and cognitive values) do not help with assessing evidential sufficiency (they perform other jobs in scientific reasoning), because to employ one blanket standard fails to recognize the complex range of sufficiency judgments in science, and because the authority of science in society requires a consideration of the social and ethical implications of erroneous judgment, thus necessitating social and ethical values as part of scientific reasoning. Implications for the assessment of scientific expertise are discussed. While science is generally our most robust and reliable form of empirical knowledge, it is by no means certain. The uncertainty endemic in science arises from science’s inductive and ampliative nature, where the evidence for any particular claim is never complete and the power of scientific generalizations is that they go beyond the evidence available, either by extending their descriptions to cases yet unseen or by positing causal relationships and/or explanatory