The vibrancy and health of political culture in democratic societies increasingly depends on the publicity and resolution of public scientific controversies. However, creating a framework for analysis that avoids reductive categorization remains a difficult task. This essay proposes a Habermasian framework of analysis for public scientific controversies and draws out its rhetorical implications. We argue that the roots of public scientific controversies are found in moments of urgency that call forth contested scientific theories into the public realm. These controversies embed epistemological disputes over knowledge-claims within pragmatic contexts, thus forcing interested parties to achieve some level of intersubjective consensus on the legitimacy of broad-based policies that fuse politics, ethics, and science. These controversies thus provide the situational grounds that make possible, if not always actual, the interaction among citizens, scientists, and legislators through rhetorical forums that feature the discursive interplay among epistemological concerns, aesthetic experience, moral valuation, and practical judgment.