Contradiction is not a sign of falsity, nor the lack of contradiction a sign of truth.

In formal logic, a contradiction is the signal of a defeat; but in the evolution of real knowledge it marks the first step in progress towards a victory.

Perhaps the greatest contradiction in our lives, the hardest to handle, is the knowledge 'There was a time when I was not alive, and there will come a time when I am not alive.' On one level, when you 'step out of yourself' and see yourself as 'just another human being', it makes complete sense. But on another level, perhaps a deeper level, personal nonexistence makes no sense at all. All that we know is embedded inside our minds, and for all that to be absent from the universe is not comprehensible. This is a basic undeniable problem of life...

I like contradictions. We have never attained the infinite variety and contradictions that exist in nature. Tomorrow I shall contradict myself. That is the one way I have of asserting my liberty, the real liberty one does not find as a member of society.

If you don't contradict yourself on a regular basis, then you're not thinking.

He disliked contradiction, and still more, arguments that were continually skipping from one thing to another, introducing new and disconnected points, so that there was no knowing to which to reply.

When a contradiction is impossible to resolve except by a lie, then we know that it is really a door.

I have often had occasion to notice how, where a direct question would fail to elicit a response, a false assumption brings instant information in the form of a contradiction.

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

Contradiction is the external limit of the propositions, tautology their substanceless centre.

Imagination could never invent the number of different contradictions that exist innately in each person's heart.

In problems of logic, contradictory statements cannot be true; in the psyche, only contradictions are true. Self-image and shadow are Siamese twins, and the psyche is equally formed by the conscious and unconscious. Whatever appears to be true on the surface is linked to an opposite truth beneath the surface. What you see is not what you get.

In the vocabulary of certain radical theorists contradictions are given the status of some deadly disease to which their opponents alone can succumb. But contradictions are the very stuff of life. If there had been a little dash of contradiction among the Gadarene swine some of them might have been saved from drowning.

There is no coincidence. Only the illusion of coincidence.