ductio

Ductio is a Latin term from ducere, meaning "to lead," traditionally used in rhetorical and scholastic contexts to denote the act or portion of a discourse that leads the audience toward the subject matter or toward a conclusion. In classical rhetoric, ductio describes the strategy of guiding listeners from familiar grounds to the matter at hand, often by establishing context, outlining premises, or presenting a line of reasoning that prepares the audience for the main argument.

In rhetorical manuals, ductio can refer to the introductory section of a speech or treatise, designed to set the frame, tone, and aims, and to secure attention and assent before the argument is developed. Some authors describe different forms of ductio, such as a general preface, a narrative bridge, or a synopsis of the ensuing argument.

In scholastic and philosophical usage, ductio is sometimes used more broadly to denote the process of argumentation that leads from premises to a conclusion; in this sense it overlaps with deduction. However, precise usage varies by author and period, and the term may be contrasted with inductio (induction) or reductio (reduction to absurdity).

Today, ductio is primarily encountered in historical discussions of Latin rhetoric and philosophy rather than as a term in contemporary rhetoric. Its significance lies in describing a broad concept of leading the audience and the mind through a discourse.