Retroduction

Retroduction is similar to induction, but it is predicated on known or assumed relationary rules and observations that contain at least one of the predicates or predictors of the rules in question. Another predicate of the relationary rule is then generalized to the observation due to the coincidence of the other predicates in both the observation and the rule.

This is commonly applied in police work to determine the initial suspects of a crime via means, motive, and opportunity, and in medical diagnostics via the patient's symptoms and established diagnostic decision trees.

The most common forms of logic systems built up through retroductive reasoning involve or are related to complexity theory.