praedicatum

Praedicatum is a term used in classical and medieval logic to denote the predicate in a categorical proposition. It is the part of the proposition that asserts a property or relation of the subject term. In a typical categorical statement such as "All dogs are mammals," "dogs" is the subject term and "mammals" is the praedicatum; the copula "are" links them. The predicate is what is predicated of the subject: the attribute, quality, or relation attributed to every instance of the subject term.

Historically, praedicatum appears in Aristotle’s syllogistic and was developed further by medieval scholastic logicians who treated predication as a fundamental operation. They distinguished subject term, predicatum, and copula within syllogisms and used the concept to analyze how a predicate could be ascribed to a subject across universal and particular propositions. The concept helped formalize the subject–predicate structure of categorical reasoning and guided the formulation of validity in syllogisms.

In modern logic, the notion of praedicatum corresponds to the predicate part of a proposition and, more generally, to the idea of a property or relation applied to a subject. In first-order logic, the praedicatum would be represented by a unary predicate P(x) or a relational predicate R(x, y) applied to the subject term.

Etymology: praedicatum derives from Latin praedicare, “to declare or predicate.”