Proposisjon

Proposisjon, in logic and philosophy, is a declarative content that can be true or false. In everyday usage, propositions are the informational content of statements that assert something about the world; sentences that express questions or commands do not express propositions.

In classical logic, a proposition is the primary unit for evaluating truth. Simple propositions express a single claim, such as "The sky is blue." Compound propositions are formed by logical connectives—and, or, not, and implies—that combine simpler propositions into more complex ones.

Historically, the concept traces to Aristotle’s study of propositions in syllogistic and to later developments in formal logic. The term derives from Latin propositio, from proponere, meaning "to put forward" or "to present."

Propositions have truth values and can be analyzed for validity, necessity, or possibility. In modal logic, some propositions are necessarily true or false, while others are contingent. In mathematics, a proposition is a statement that can be proved or disproved.

Examples include "2+2=4" and "The cat is on the mat." A sentence such as "Is it raining?" or "Close the door" is not a proposition because it does not assert a fact.

In Norwegian, proposisjon commonly refers to the same logical or mathematical concept. It is distinct from preposisjon, the term for a grammatical preposition.