“This world is a comedy to those that think, a tragedy to those that feel.”

“The world is a tragedy to those who feel, but a comedy to those who think.”

“I have often said, and oftener think, that this world is a comedy to those that think, a tragedy to those that feel – a solution of why Democritus laughed and Heraclitus wept.”

“Men are often capable of greater things than they perform. They are sent into the world with bills of credit, and seldom draw to their full extent.”

“In science, mistakes always precede the truth.”

“When people will not weed their own minds, they are apt to be overrun by nettles.”

“The whole secret of life is to be interested in one thing profoundly and in a thousand things well.”