Curiosity is a delicate little plant that, aside from stimulation, stands mainly in need of freedom.

The pursuit of truth and beauty is a sphere of activity in which we are permitted to remain children all our lives.

This has been done elegantly by Minkowski; but chalk is cheaper than grey matter, and we will do it as it comes.

When you examine the lives of the most influential people who have ever walked among us, you discover one thread that winds through them all. They have been aligned first with their spiritual nature and only then with their physical selves.

Every day I remind myself that my inner and outer life are based on the labors of other men, living and dead, and that I must exert myself in order to give in the same measure as I have received and am still receiving.

To put it boldly, it is the attempt at a posterior reconstruction of existence by the process of conceptualization.

The bitter and the sweet come from the outside, the hard from within, from one's own efforts.