Abduction is the process of inferring the best explanation for observations. It begins with something that needs explaining and proposes a hypothesis that would make the observation understandable.
For example, if a person finds the ground wet in the morning, they may infer that it rained overnight. Rain is not proven by the wet ground—sprinklers, dew, or a burst pipe could also explain it—but it may be the simplest or most plausible explanation. Abductive reasoning is therefore often called “inference to the best explanation.”
The American philosopher and logician Charles Sanders Peirce developed the modern concept of abduction in the late 19th century. He treated it as a way of generating explanatory hypotheses, which can then be examined through deduction and tested against evidence. This makes abduction especially important in science, medicine, detective work, and artificial intelligence.
Abduction is different from deduction, which guarantees a conclusion when the premises are true, and induction, which generalizes from repeated observations. Syllogism is a form of argument, not the specific name for inferring an explanation. An abductive conclusion remains provisional because a later observation may reveal a better account.