Retroductive Analogy: How to and How Not to Make Claims of Good Reasons to Believe in Evolutionary and Anti-Evolutionary Hypotheses

This paper describes an argumentative fallacy we call ‘Retroductive Analogy.’ It occurs when the ability of a favored hypothesis to explain some phenomena, together with the fact that hypotheses of a similar sort are well supported, is taken to be sufficient evidence to accept the hypothesis. This fallacy derives from the retroductive or abductive form of reasoning described by Charles Sanders Peirce. According to Peirce’s account, retroduction can provide good reasons to pursue a hypothesis but does not, by itself, provide good reasons to believe the hypothesis. In successful applications of retroduction, pursuit leads to the accumulation of evidence. In retroductive analogy, comparison with other successful hypotheses is substituted for the genuine pursuit of evidence. We describe a case from ecological genetics in which retroduction plays a legitimate role as the initial phase of an ongoing research program that serves to accumulate genuine evidence for a hypothesis. We also examine two contexts in which the fallacy of retroductive analogy occurs: in defenses of Intelligent Design Theory and in defense of some hypotheses in Evolutionary Psychology.