Inductive Expansion and Nonmonotonic Reasoning

Abstract

In his early writings (e.g. Harvard Lectures of 1865, Peirce [1982]), Peirce followed Aristotle in defining inductive argument formally as the apogogic inversion of valid syllogistic argument where the major premise of the syllogism becomes the conclusion of the induction and the erstwhile conclusion becomes a premise of the induction. Peirce contrasted this kind of argument with hypothetic argument where the conclusion is the minor premise of the categorical syllogism and the premise is the erstwhile conclusion. He then pointed out that both hypothetic and inductive reasoning are ampliative in contrast to deductive reasoning that is explicative.