Introduction & Causal Concepts

Summary

Surveys eight historical milestones in causal thinking from Hippocrates and miasma theory through Snow, germ theory, Goldberger's pellagra work, Framingham, the agent-host-environment triad, and One Health, framing them as a pendulum between biological mechanism and population-environment perspectives. Develops inductive, deductive, and Bayesian reasoning anchored in Bacon, Hume, Popper, Bayes, and Kuhn, then introduces directed acyclic graphs with their three structural elements of chain, fork, and collider plus the Baron-Kenny mediation procedure with its modern counterfactual successors. Closes with the component-cause model of necessary and sufficient causes and previews the counterfactual framework that underpins modern causal inference.