This is my last one for the month, it seems.

"If you would be a real seeker after truth, it is necessary that at least once in your life you doubt, as far as possible, all things." - Rene Descartes

"The most perfidious way of harming a cause consists of defending it deliberately with faulty arguments." - Friedrich Nietzsche

"Education is the ability to listen to almost anything without losing your temper or your self-confidence." - Robert Frost

"We confess our little faults to persuade people that we have no large ones." - Francois de La Rochefoucauld

"I used to think that the brain was the most wonderful organ in my body. Then I realized who was telling me this." - Emo Phillips