No man can be a good teacher unless he has feelings of warm affection toward his pupils and a genuine desire to impart to them what he believes to be of value.

What will be the good of the conquest of leisure and health, if no one remembers how to use them?

Science, in its ultimate ideal, consists of a set of propositions arranged in a hierarchy, the lowest level of the hierarchy being concerned with particular facts, and the highest with some general law, governing everything in the universe. The various levels in the hierarchy have a two-fold logical connection, travelling one up, one down; the upward connection proceeds by induction, the downward by deduction.

The governors of the world believe, and have always believed, that virtue can only be taught by teaching falsehood, and that any man who knew the truth would be wicked. I disbelieve this, absolutely and entirely. I believe that love of truth is the basis of all real virtue, and that virtues based upon lies can only do harm.

The sea, the stars, the night wind in waste places, mean more to me than even the human beings I love best.

Be scrupulously truthful, even if the truth is inconvenient, for it is more inconvenient when you try to conceal it.

Thought is subversive and revolutionary, destructive and terrible, Thought is merciless to privilege, established institutions, and comfortable habit. Thought is great and swift and free.