Predicables

Part of speech: noun

Definitions

1. The five general classes of term that can be said of a subject in Aristotelian logic, namely genus, species, difference, property and accident
2. Categories of attributes in classical logic that describe what can be asserted about a thing, such as its genus, species, difference, property or accident
3. In traditional logic, the fivefold classification of ways a term may be affirmed of a subject, including genus, species, differentia, proprium and accident

Etymology: "Predicables" is the plural of "predicable," a term from Aristotelian logic for the kinds of attribute a predicate can assert of a subject. The singular "predicable" traces back through Latin "praedicabilis," meaning "that can be predicated" or "that can be asserted," built from "praedicare," to declare or proclaim, and the verb "predicate" that English borrowed from the same Latin root. The plural is used in the logical tradition inherited from Aristotle's "Topics," where a standard list of five predicables was set out: genus, species, difference, property, and accident. Each names a different way in which a predicate can relate to the thing it describes. Genus says what a thing is in general terms, species narrows that down, difference separates one species from its neighbours, property belongs to a thing necessarily but not essentially, and accident belongs to it contingently. Medieval scholastic logicians, notably Porphyry in his introduction to Aristotle's "Categories," kept the scheme alive, so the word stayed firmly attached to classroom logic.