"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."

"Why is it that we entertain the belief that for every purpose odd numbers are the most effectual?"

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

"Weakness of attitude becomes weakness of character."

"If you can't return a favor, pass it on."

"Dreaming permits every one of us to be quietly and safely insane every night of our lives."

"We judge the future by the past. Achieving success is one's ability to look at yesterday, cease today and capture tomorrowa€?s opportunity."

"A snake lurks in the grass."

"If wisdom were on sale in the open market, the stupid would not even ask the price."