Today many scholars seem to agree that citizens should be involved in expert deliberations on science and technology issues. This interest in public deliberation has gained attraction in many practical settings, especially in the European Union, and holds the promise of more legitimate governance of science and technology. In this article, the authors draw on the European Commission’s (EC) report ‘‘Taking the European Knowledge Society Seriously’’ to ask how legitimate these efforts to ‘‘democratize’’ scientific expertise really are. While the report borrows from deliberative democrats’ normative accounts of legitimacy, the authors identify a tension between the principles for legitimate rule prescribed by deliberative democratic theory and the report’s celebration of diversity and dissent. While this inconsistency suggests that the legitimacy of deliberative governance arrangements is justified on empirical rather than normative grounds, it remains an open question whether studies of science and technology offer enough empirical support for such a justification. In this article, the authors address this pressing question and propose three possible responses.