We must... maintain that mathematical geometry is not a science of space insofar as we understand by space a visual structure that can be filled with objects - it is a pure theory of manifolds.

If error is corrected whenever it is recognized as such, the path of error is the path of truth.

You see, there is no more purpose or meaning in the world than you put into it.

It appears that the solution of the problem of time and space is reserved to philosophers who, like Leibniz, are mathematicians, or to mathematicians who, like Einstein, are philosophers.

Philosophy is regarded by many as inseparable from speculation. ... Philosophy has proceeded from speculation to science.

Visual forms are not perceived differently from colors or brightness. They are sense qualities, and the visual character of geometry consists in these sense qualities.

Occasionally one speaks... of signals or signal chains. It should be noted that the word signal means the transmission of signs and hence concerns the very principle of causal order.

...the mathematician uses an indirect definition of congruence, making use of the fact that the axiom of parallels together with an additional condition can replace the definition of congruence.

I don’t want fame, money, or duty. I want to close my eyes and see your loving beauty.

In order to know the world from the outside, you must know yourself from the inside.

Victories turned inside outBut no surrenderCemeteries of remorseThe beaten champion sobbingGhosts move in to shield his tears

The future has a way of arriving unannounced.

Bryan Lee O'Malley has been alive since he was born and will lives until he dies.

What else goes wrong for a woman-except her marriage?

Nothing, it is true, is more common than for both Science and Art to pay homage to the spirit of the age, and for creative taste to accept the law of critical taste.

Labor cannot stand still. It must not retreat. It must go on, or go under.

One can never outlive one's vanity.

The harder [role] the better. Definitely. When somebody turns around and says, "She can't do that," then that's the one I want to do.