"Heresy is a cradle; orthodoxy a coffin."
"What light is to the eyes - what air is to the lungs - what love is to the heart, liberty is to the soul of man."
"In the republic of mediocrity, genius is dangerous."
"Colleges are places where pebbles are polished and diamonds are dimmed."
"The superior man is the providence of the inferior.
He is eyes for the blind, strength for the weak, and a shield for the defenseless.
He stands erect by bending above the fallen.
He rises by lifting others."
"I will not attack your doctrines nor your creeds if they accord liberty to me.
If they hold thought to be dangerous - if they aver that doubt is a crime,
then I attack them one and all, because they enslave the minds of men."
"It is a thousand times better to have common sense without education than to have education without common sense."
"Reason, observation, and experience; the holy trinity of science."
"Anger blows out the lamp of the mind. In the examination of a great and important question, everyone should be serene, slow-pulsed and calm."