» It is not the strongest of the species that survive, nor the most intelligent, but the one most responsive to change.
» It is a cursed evil to any man to become as absorbed in any subject as I am in mine.
» I am not the least afraid to die.
» I love fools experiments. I am always making them.
» A man's friendships are one of the best measures of his worth.
» What a book a devil's chaplain might write on the clumsy, wasteful, blundering, low, and horribly cruel work of nature!
» The highest possible stage in moral culture is when we recognize that we ought to control our thoughts.
» A man who dares to waste one hour of his life has not discovered the value of life.
» I fully subscribe to the judgement of those writers who maintain that of all the differences between man and the lower animal, the moral sense of conscience is by far the most important....It is the most noble of all the attributes of man.
» ...it is always advisable to perceive clearly our ignorance.