The ontology of epidemics—A value-dependent realist account of epidemics

Rationale: Charters and Heitman have recently argued that epidemic status is lost once the disease becomes ‘accepted into people's daily lives and routines, becoming endemic—domesticated—and accepted’. This is a normativist, subjectivist approach to epidemic classification; that is, it is both value-laden, and dependent on the attitudes of the population. In this article, we argue for an alternative approach: a value-dependent realist account of epidemic-status. Aims and Objectives: We aim to provide an ontological account of epidemics, with a particular focus on their endings. We do not attempt to present a historical account of previous epidemics, or why their endings were declared, but rather consider the theoretical underpinnings of such declarations. Further, our account is meant to be more prescriptive than descriptive; that is to say, even if public health does not currently view epidemics in the manner we advocate, the metaphysic of epidemics we advocate is, we believe, that which public health should ultimately endorse. Method: The methodologies employed in this article are primarily those common to the philosophy of public health, philosophy of medicine and metaphysics; namely, conceptual analysis grounded by practical considerations. Results: Charters and Heitman have recently argued that epidemic status is lost once the disease becomes ‘accepted into people's daily lives and routines, becoming endemic—domesticated—and accepted’. This is a normativist, subjectivist approach to epidemic classification; that is, it is both value-laden, and dependent on the attitudes of the population. In this article, we argue for an alternative approach: a value-dependent realist account of epidemic-status. Conclusion: To frame the argument we draw from complexity theory, arguing that human populations can be viewed as complex systems, and epidemic-status as an emergent property of a complex system. We propose aggregating the normative standards relevant to labeling a disease as an epidemic, and use this as our indicator for both the beginning, and the end of epidemics. An epidemic ends, we argue, once the burden of disease drops below an objective but distinctly normative ‘epidemic threshold’.