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

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'.