abductive-reasoninglisted

# Abductive Reasoning ## Overview Abduction — *inference to the best explanation* — is the only mode of reasoning that introduces new ideas. Deduction works out consequences; induction generalizes instances; **abduction generates the hypotheses themselves** (Peirce, 1903). Formal schema: *The surprising fact C is observed. But if A were true, C would be a matter of course. Hence, there is reason to suspect A is true.* The "best" qualifier carries the weight: consistent-with-evidence is not enough — the hypothesis must beat rivals on coverage, simplicity, prior probability, and predictive power (Harman 1965; Lipton 2004). Composes with [`bayesian-reasoning`](../bayesian-reasoning/SKILL.md) (Bayes scores hypotheses abduction generates), [`occams-razor`](../occams-razor/SKILL.md) (simplicity criterion), [`critical-thinking`](../critical-thinking/SKILL.md) (competing-hypotheses analysis), and `debugging-and-error-recovery` (technical debugging is iterated abduction). ## When to Use - A surprising observation needs explanation (bug, symptom, outage, customer behavior, financial anomaly) - A diagnostic decision must be made under uncertainty (medical, technical, investigative) - Someone is treating "consistent with X" as proof of X - A team has converged on one explanation without enumerating alternatives - An investigation has stalled at the first plausible-sounding hypothesis **Not when:** the problem is deductive (math, formal logic); evidence is sufficient for direct me