CONCEPT
Abduction
Peirce's third mode of inference — the logic of discovery — that moves from a surprising fact to a hypothesis that would, if true, render the fact unsurprising.
Abduction is Peirce's name for the inference that generates new hypotheses. Unlike deduction (which extracts what premises already contain) or induction (which extends observed patterns to unobserved cases), abduction proposes something that has not been observed — a new pattern, a new structure, a new explanation. The logical form is deceptively simple: 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. Peirce regarded abduction as the most philosophically neglected and most important of the three inferential modes, because it is where new ideas actually come from. The AI moment has made abduction the central diagnostic question: can machines perform it, or only simulate it?
In The You On AI Field Guide
The logical form of abduction conceals a profound difficulty: where does the hypothesis come from? It is not derived from the evidence. It is not a deductive consequence of any premise. It is not an inductive generalization. It arrives