3.4 Reasoning about Causal Explanations

Causation vs correlation (the master distinction): two events moving together (correlation) may be: (i) cause and effect; (ii) effect and cause (reversed); (iii) both effects of a third factor (confounder — the classic: ice-cream sales correlate with drownings; the confounder is summer); (iv) coincidence. Claiming causation from bare correlation is the post hoc ergo propter hoc fallacy ("after it, therefore because of it").Mill's methods (the classical toolkit — name all four, illustrate one):1. Method of agreement — the factor common to all cases of the effect (every food-poisoning victim ate the buffet's potato salad);2. Method of difference — the factor present where the effect occurs and absent where it does not (the two households, identical except the water source);3. Method of concomitant variations — the effect varies with the suspected cause (dose- response: more asbestos exposure, more disease);4. Method of residues — subtract known causes; what remains accounts for the rest (the forensic accountant's method).The modern checklist for a causal claim: strength of association, consistency across studies, temporal precedence (cause before effect), dose-response, plausibility, and exclusion of confounders — the structure of both epidemiology and accident investigation.The legal application (where this unit becomes law): causal reasoning is liability reasoning:• Criminal law: the prohibited result must be attributable to the act (the act must be a substantial and operating cause; intervening…