Our most important thoughts are those which contradict our emotions.
Paul Valéry 
The sad truth is that most evil is done by people who never make up their minds to be good or evil.
Hannah Arendt
Theory, which is expectation, always determines criticism, and never more than when it is unconscious.
John Crowe Ransom
Kindness is in our power, even when fondness is not.
Samuel Johnson
Simplicity is complexity resolved.
Constantin Brancusi
Children have never been very good at listening to their elders, but they have never failed to imitate them.
James Baldwin
Try to learn something about everything and everything about something.
Inscribed on Thomas Huxley’s memorial
The whole secret of life is to be interested in one thing profoundly and in a thousand things well.
Horace Walpole
The only interesting answers are those which destroy the questions.
Susan Sontag
Imagine how much harder physics would be if electrons had feelings.
Richard Feynman