There are two tragedies in life. One is to lose your heart's desire. The other is to gain it.
No man who is occupied in doing a very difficult thing, and doing it very well, ever loses his self-respect.
The power of accurate observation is frequently called cynicism by those who have not got it.
Progress is impossible without change, and those who cannot change their minds cannot change anything.
A life spent making mistakes is not only more honourable, but more useful than a life spent doing nothing.