This document is a preprint (working paper) and has not undergone peer review. Public health has historically developed as a science of collective action, closely intertwined with the formation of the modern state and the governance of populations. Its authority has been grounded in quantification, prevention, and planning, as well as in hierarchical regimes of evidence designed to rationalize public decision-making. Evidence-based public health represents the most stabilized contemporary expression of this model. Yet current ecological, sanitary, social, and informational crises reveal a persistent mismatch between the accumulation of scientific knowledge and its capacity to orient collective action. Robust evidence increasingly coexists with policy inertia, polarized controversies, and declining trust in expert mediation. This paper develops a theoretical framework for understanding public health as a reflexive science of governance under conditions of complexity, uncertainty, and contested legitimacy. Drawing on complexity theory, post-normal science, and science and technology studies, it argues that the central challenge of contemporary public health lies not only in the production of robust evidence, but in its capacity to orient collective action in politically and socially unstable environments. It proposes a reconfiguration of public health as a reflexive, dialogical, and normatively explicit field, capable of integrating epistemic rigor, institutional legitimacy, and social justice. This version is shared to facilitate early dissemination and feedback prior to submission to a peer-reviewed journal.
ERIC BERNIER (Thu,) studied this question.