predications

Predication is the act of ascribing a property or relation to a subject within a proposition. In everyday language, predication links a subject term to a predicate term, as in “The leaf is green.” In formal logic, predication generalizes this idea: a predicate is the property or relation that can be true of one or more objects, and sentences express predications that can be true or false.

Historically, predication was central to Aristotle’s syllogistic, where a categorical proposition asserts that all members of a subject class have a certain predicate attribute (for example, “All humans are mortal”). In contemporary logic, predicates are applied to variables and can express relations of various arities. For example, in plain language one can render universal predication as “All dogs are mammals” (every x, if x is a dog, then x is a mammal), and existential predication as “There exists a dog that is brown.” More complex predications use relations such as loves(John, Mary) or gives(donor, recipient, gift), illustrating the relational side of predication.

Predication also has important distinctions in linguistics and philosophy. Categorical predication assigns a property to a subject, while relational predication assigns a relation between the subject and others. Predication underpins truth conditions: a predication is true if the subject bears the stated property or stands in the stated relation in the given world or model, and false otherwise. Negation, modality, and quantification interact with predications to form more complex statements.