Abduction (logic)

Abduction is the kind of practical logic which answers questions of the type "how did this come about?". It produces answers which are not guaranteed to be correct. Consider the observation that the lawn is wet in the morning. How did that happen? In London, the answer is most often that it rained. But in Los Angeles it is much more likely that someone left the sprinkler on.

Abduction is logical inference which goes from an observation to a theory which accounts for the observation. It makes the simplest and most likely explanation. In abductive reasoning, unlike in deductive reasoning, the premises do not guarantee the conclusion. Abductive reasoning is "inference to the best explanation".

The philosopher Charles Sanders Peirce (1839–1914) introduced abduction into modern logic.