University of Alberta Dictionary of Cognitive Science: Proposition

The proposition is a concept borrowed by cognitive psychologists from linguists and logicians. The propostion is the most basic unit of meaning in a representation. It is the smallest statement that can be judged either true or false. Anderson (1990) gives the following example of a setence divided up into its constituent propositions:

"Nixon gave a beautiful Cadillac to Brezhnev, who was the leader of the USSR."

This sentence can be divided into three propositions:

Nixon gave a Cadillac to Brezhnev.
The Cadillac was beautiful.
Brezhnev was the leader of the USSR.

A popular view in cognitive psycyhology is that the mind is structured much like a language. In such a structure, propositions function as basic units of representation--or the building blocks--of the mind. It is the content of the propositions, the connections between propositions, and the strength of the connections between propositions that determine the structure of mind.

References:

Anderson, J.R. (1990). Cognitive psychology and its implications (3rd ed.). New York: W. H. Freeman.