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. Retroduction is often identified with abduction or abductive reasoning, and the two terms are often used interchangeably.
According to Sayer (1992, p.107), retroduction is a "...mode of inference in which events are explained by postulating (and identifying) mechanisms which are capable of producing them...". [1] It is recognized as the key epistemological process by critical realists. [2]
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.