The Commens Dictionary
Quote from ‘On the Three Kinds of Reasoning [R]’
That kind of reasoning by which we are more or less inclined to believe in a theory because it explains facts that without the theory would be very surprising is what I call Retroduction, or reasoning from consequent to antecedent. To understand the legitimacy of this kind of reasoning (often and often as it deceives us,) is to understand the legitimacy, the truth-leading power of all reasoning.
MS [R] 755:14
‘Retroduction’ (pub. 12.03.18-17:14). Quote in M. Bergman & S. Paavola (Eds.), The Commens Dictionary: Peirce's Terms in His Own Words. New Edition. Retrieved from http://www.commens.org/dictionary/entry/quote-three-kinds-reasoning-r-1.