Abstract
This essay analyzes the concept of public trust in science and offers some guidance for ethicists, scientists, and policymakers who use this idea defend ethical rules or policies pertaining to the conduct of research. While the notion that public trusts science makes sense in the abstract, it may not be sufficiently focused to support the various rules and policies that authors have tried to derive from it, because the public is not a uniform body with a common set of interests. Well-focused arguments that use public trust to support rules or policies for the conduct of research should specify (a) which public is being referred to (e.g. the general public or a specific public, such as a particular community or group); (b) what this public expects from scientists; (c) how the rule or policy will ensure that these expectations are met; and (d) why is it important to meet these expectations