“The liar's punishment is, not in the least that he is not believed, but that he cannot believe anyone else.”

The people who get on in this world are the people who get up and look for the circumstances they want, and if they can't find them, make them.

Youth is wasted on the young.

A life spent making mistakes is not only more honorable, but more useful than a life spent doing nothing.

You see things; you say, 'Why?' But I dream things that never were; and I say, 'Why not?'

The reasonable man adapts himself to the world: the unreasonable one persists in trying to adapt the world to himself.

Progress is impossible without change, and those who cannot change their minds cannot change anything.

The reasonable man adapts himself to the world; the unreasonable one persists in trying to adapt the world to himself. Therefore all progress depends on the unreasonable man.