Credible fact-making for policy demands the same legitimating moves as are required for credible politics. Experts, like politicians, must represent the world in ways that respect diverse standpoints, aggregate disparate opinions to produce a semblance of objectivity, and find persuasive ways to bridge gaps between available and ideal states of knowledge. Every society, moreover, commands its own culturally recognized approaches to producing and testing public knowledge, and expert practices must conform to these to be broadly accepted. Insisting on the superior authority of science without attending to the politics of reason and persuasion will not restore trust in either knowledge or power. Instead, trust can be regained with more inclusive processes for framing policy questions, greater attentiveness to dissenting voices and minority views, and more humility in admitting where science falls short and policy decisions must rest on prudence and concern for the vulnerable.

Courts routinely resolve factual disputes as an adjunct to settling legal controversies, and such fact-finding frequently involves scientific and technical evidence. It is important to ask what intellectual resources judges bring to this task. Instead of assessing how much science judges know or understand, this essay focuses on the judge's role in articulating and reinforcing prevailing cultural attitudes toward science. Background judicial assumptions matter at three significant junctures. First, judges maintain the lay-expert boundary by deciding whether an issue demands expert testimony at all. Second, judges act as epistemological gatekeepers, by determining which expert claims and ways of reasoning are entitled to deference and which are not. Third, judges decide how to classify and categorize things of uncertain ontological status as a prelude to applying legal rules. Each kind of decision offers a window into judicial common sense, a relatively neglected topic in studies of law and science.