Beware of dissipating your powers; strive constantly to concentrate them.
We are never further from our wishes than when we imagine that we possess what we have desired.
In the realm of ideas, everything depends on enthusiasm; in the real world, all rests on perseverance.
God made man simple, but how he changed and got complicated is hard to say.
Man is not born to solve the problems of the universe, but to find out what he has to do ... within the limits of his comprehension.
Everybody undertakes what he sees another successful in, whether he has the aptitude for it or not.