The Commens Dictionary

Quote from ‘The Rationale of Reasoning’

A Proposition is any product of language which has the form that adapts it to instilling belief into the mind of the person addressed, supposing him to have confidence in its utterer. [—] A Proposition is nearly the same as an “Assertion.” The distinction which I use the two words to mark is that an Assertion includes no more than it is the intention of the Utterer to declare, while the Proposition includes all that he does declare, which is inevitably considerably more than he intends.