"This only is certain, that there is nothing certain; and nothing more miserable and yet more arrogant than man."

"No mortal man, moreover is wise at all moments."

"In these matters the only certainty is that nothing is certain."

"In comparing various authors with one another, I have discovered that some of the gravest and latest writers have transcribed, word for word, from former works, without making acknowledgment."

"The best plan is to profit by the folly of others."

"The only certainty is that nothing is certain."

"A Sunday school is a prison in which children do penance for the evil conscience of their parents."

"Time is nature's way of keeping everything from happening at once."

"Courage is very important. Like a muscle, it is strengthened by use."

"The effect of one upright individual is incalculable."

"Your paradigm is so intrinsic to your mental process that you are hardly aware of its existence, until you try to communicate with someone with a different paradigm."

"Too many people miss the silver lining because they're expecting gold."