Epidemiology
Source: John Snow, On the Mode of Communication of Cholera, 1855; Austin Bradford Hill, Proceedings of the Royal Society of Medicine 58, 1965 Institution: London; London School of Hygiene and Tropical Medicine
Finding
John Snow mapped cholera deaths in Soho during the 1854 London epidemic, identifying the Broad Street pump as the source. By plotting cases geographically, he demonstrated waterborne transmission, overturning miasma (bad air) theory — a decade before Koch identified Vibrio cholerae (1884). Snow did not know what was in the water; the pattern of clustering revealed the cause. He persuaded authorities to remove the pump handle; the outbreak subsided. Hill’s criteria for causation (1965) formalized the logic: strength, consistency, specificity, temporality, biological gradient, plausibility, coherence, experiment, analogy.
Pattern Mapping
Honesty — Snow let the data speak against established authority. Miasma theory was held by respected physicians. The map did not argue; it showed. Snow’s honesty was following evidence against consensus.
Non-fabrication — Miasma theory fabricated a cause (bad air) that did not exist. Not cynically — it was the best available explanation — but it was still structure that did not correspond to reality. Snow replaced fabricated cause with observed pattern.
Alignment — Hill’s criteria are alignment conditions for causal claims. Temporality: cause must precede effect. Biological gradient: more exposure, more disease. Consistency: the relationship holds across populations. Each criterion tests alignment between claim and reality.
Connections
- Graph Theory — Snow’s map IS a graph; disease clusters reveal network structure
- Vaccination — herd immunity thresholds are epidemiological calculations
- Diagnosis — population patterns inform individual diagnostic priors
- Scientific Method — Hill’s criteria formalize causal inference in observational science
- Opioid Crisis — epidemiological data revealed the crisis pattern before institutions acted
Status
Snow (1855). Johnson, The Ghost Map (2006). Hill (1965). The mapping to the five properties is this project’s structural interpretation.
The mapping to the five properties is this project’s structural interpretation.