 Syllogisms are patterns of logical argumentation. A syllogism with merely probable premises was called dialectical in medieval and Renaissance philosophy. Since dialectic was the “art of rational disputation” or “controversial inquiry” (ars disserendi), and disputation was a characteristic activity of universities in the Middle Ages, argumentation with probable propositions possessed an enormous significance for medieval thought. It is also characteristic of logic-fed scholasticism that probable reasoning was mainly conceived as logical deduction from probable  premises.[31]  After the rise of Aristotelianism, these premises were mostly framed as endoxa. Thomas Aquinas writes: