Quote by Ludwig Wittgenstein

A tautology's truth is certain, a proposition's possible, a contradiction's impossible.

— Ludwig Wittgenstein

“Tautology and contradiction are, however, not senseless; they are part of the symbolism, in the same way that “0” is part of the symbolism…

— Ludwig Wittgenstein

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

— Mark Lilla

Lies are an absence of facts and, in many cases, a direct contradiction of them.

— Daniel Levitin

When somebody says that all statements are false, the obvious problem is that as an assertion it's self-defeating.

— Henry Flynt

There are no contradictions in truth.

— Nicholas Zounis

Two truths cannot contradict one another.

— Anonymous

Anything that is said is not the truth. It is a statement of truth, and no statement is the truth.

— Barry Long

Our reasonings are grounded upon two great principles, that of contradiction, in virtue of which we judge false that which involves a contradiction, and…

— Gottfried Leibniz

Propositions on which all men are in agreement are true: if they are not true we have no truth at all.

— Georg C. Lichtenberg

“Most of the propositions and questions to be found in philosophical works are not false but nonsensical.”

— Ludwig Wittgenstein

“I'll give you a hint. Contradictions do not exist. Whenever you think that you are facing a contradiction, check your premises. You will find…

— Ayn Rand