Look deep into nature, and then you will understand everything better.

If at first the idea is not absurd, then there is no hope for it.

The most important human endeavor is the striving for morality in our actions. Our inner balance and even our very existence depend on it. Only morality in our actions can give beauty and dignity to life.

The series of integers is obviously an invention of the human mind, a self-created tool which simplifies the ordering of certain sensory experiences.

A finely tempered nature longs to escape from the personal life into the world of objective perception and thought.

Strive not to be a success, but rather to be of value.

There exists a passion for comprehension, just as there exists a passion for music. That passion is rather common in children, but gets lost in most people later on. Without this passion there would be neither mathematics nor natural science.