ABSTRACT
Charles Sanders Peirce (1839-1914) used the term ‘abduction’ for the type of reasoning or method of discovery that moves from a given set of facts to an explanatory hypothesis.1 Abduction is illustrated in science by the way Kepler reached his hypothesis about the elliptical path of Mars from the observed irregularities in the movement of Mars. For Peirce, the founder of pragmatism, abduction was one of three forms of inference: induction, deduction, and abduction. Before discussing abduction, it is useful to describe induction and the hypothetico-deductive method by way of contrast.
