Clear Quote by Ludwig Wittgenstein

The meaning of a proposition is the method of its verification.

— Moritz Schlick

We say that a sentence is factually significant to any given person, if, and only if, he knows how to verify the proposition which…

— A.J. Ayer

The fundamental principle in the analysis of propositions containing descriptions is this: Every proposition which we can understand must be composed wholly of constituents…

— Bertrand Russell

“Any proposition containing the word "is" creates a linguistic structural confusion which will eventually give birth to serious fallacies.”

— Alfred Korzybski

“Even in ordinary conversation, the ideas connected with the word Logic include at least precision of language, and accuracy of classification: and we perhaps…

— John Stuart Mill

We can no longer assert any single proposition, unless we guard ourselves by enumerating countless conditions which must be assumed.

— Aleister Crowley

“Propositions become either pure or impure, not true or false.”

— Mark Lilla

No Discourse whatsoever, can End in absolute Knowledge of Fact.

— Thomas Hobbes

The propositions of mathematics are devoid of all factual content; they convey no information whatever on any empirical subject matter.

— Carl Gustav Hempel

Whatever is clearly expressed is well wrote.

— Mary Wortley Montagu

When I say or write something, there are actually a whole lot of different things I am communicating. The propositional content (i.e., the verbal…

— David Foster Wallace

The validity of mathematical propositions is independent of the actual world-the world of existing subject-matters-is logically prior to it, and would remain unaffected were…

— Cassius Jackson Keyser