A science which hesitates to forget its founders is lost.

Wisdom alone is true ambition's aim, wisdom is the source of virtue and of fame; obtained with labour, for mankind employed, and then, when most you share it, best enjoyed.

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

A race preserves its vigor so long as it harbors a real contrast between what has been and what may be; and so long as it is nerved by the vigor to adventure beyond the safeties of the past. Without adventure civilization is in full decay.

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

Life is the enjoyment of emotion, derived from the past and aimed at the future.

The great achievements of the past were the adventures of the past. Only the adventurous can understand the greatness of the past.