While the right to talk may be the beginning of freedom, the necessity of listening is what makes that right important."

"When all think alike, then no one is thinking."

"The thinker dies, but his thoughts are beyond the reach of destruction. Men are mortal; but ideas are immortal."

"The study of error is not only in the highest degree prophylactic, but it serves as a stimulating introduction to the study of truth."

"The opposition is indispensable. A good statesman, like any other sensible human being, always learns more from his opponents than from his fervent supporters."