Virtue consists, not in abstaining from vice, but in not desiring it.
No man who is occupied in doing a very difficult thing, and doing it very well, ever loses his self-respect.
A life spent making mistakes is not only more honourable, but more useful than a life spent doing nothing.
The power of accurate observation is frequently called cynicism by those who have not got it.
Success does not consist in never making mistakes but in never making the same one a second time.