The test of a first-rate intelligence is the ability to hold two opposed ideas in the mind at the same time, and still retain the ability to function.
F. Scott Fitzgerald
It is the mark of an educated mind to be able to entertain a thought without accepting it.
Education enables you to express assent or dissent in graduated terms.
Education is the ability to listen to almost anything without losing your temper or your self-confidence.
To change an opinion without a mental process is the mark of the uneducated.
To have doubted one’s own first principles is the mark of a civilized man.
Oliver Wendell Holmes