It belongs to the self-respect of intellect to pursue every tangle of thought to its final unravelment.

Nature is probably quite indifferent to the aesthetic preferences of mathematicians.

Do not teach too many subjects and what you teach, teach thoroughly.

Thus the negative perception is the triumph of consciousness.

Each generation criticizes the unconscious assumptions made by its parent. It may assent to them, but it brings them out in the open.

Peace is self-control at its widest-at the width where the "self" has been lost, and interest has been transferred to coordinations wider than personality.

The guiding motto in the life of every natural philosopher should be, seek simplicity and distrust it.