universal proposition

In traditional logic, a universal proposition is a statement where a predicate is affirmed or denied of the entire subject. These propositions are fundamental to syllogistic reasoning, a method of inference developed by Aristotle.1

Universal propositions come in four basic forms, often represented by letters:
* A-proposition: "Every S is P" (e.g., "Every Greek is human").21
* E-proposition: "No S is P" (e.g., "No human is immortal").21
* I-proposition: "Some S is P" (e.g., "Some Greek is bearded").21
* O-proposition: "Some S is not P" (e.g., "Some Greek is not bearded").21

These forms differ in their "quantity" (universal or particular) and "quality" (affirmative or negative). Universal propositions are distinct from hypothetical propositions, which express conditional relationships.12