Entropy of plagues: A measure for assessing the loss of social cohesion due to epidemics

The authors have asked the question what kind of illumination might be given to a series of historical events through the application of operations research techniques. The question is addressed by means of a model. In that model the authors compare the evidence for the collapse of civil authority during selected plagues of the 14th-17th century against the value for a casualty based entropy. The entropy is computed from time series of mortality data taken from the historical record of the selected period. This contribution builds upon previously published work in which entropy, computed from military casualites, becomes a predictor of combat outcome. The conjecture is advanced that mortality based entropy calculations reveal the impact of the plague mortality on societal structure. Comparison with the work of Dupaquier on the scaling of crises is made. Suggested extensions to additional societal phenomena are advanced.