TopicsAristotle

The Topics is Aristotle's treatise on dialectic, the art of reasoning from generally accepted opinions (endoxa) rather than from first principles that are known to be true. It is the fifth work of the Organon in the traditional order. Aristotle states his purpose at the outset: to find a method by which we can reason from accepted opinions about any problem set before us, and, when defending a position, avoid saying anything self-contradictory. Dialectic is useful for training, for conversation, and for the philosophical sciences, where it helps in examining first principles that demonstration cannot prove.

Book I lays the foundations. Aristotle distinguishes dialectical, demonstrative, and merely contentious reasoning. He identifies four materials of dialectical argument: accident, property, genus, and definition. He also describes the instruments for obtaining premises: securing propositions, distinguishing the senses of terms, finding differences, and investigating similarities. Books II through VII supply the topoi themselves, the "places" from which arguments can be drawn, organized by predicable. Book II treats accident; Book III, questions of better and worse; Book IV, genus; Book V, property; Books VI and VII, definition and sameness. Book VIII turns to the practice of question-and-answer debate: how to arrange questions, conceal the conclusion until the right moment, and block an opponent's advance.

The Topics is the companion to the Sophistical Refutations, which many read as its appendix on fallacious argument. Together they fix the classical theory of informal reasoning. Cicero's rhetorical topoi, the medieval handbooks of disputation, and modern work on argumentation schemes all descend from this map of how common opinions can be made to yield consistent conclusions.