The hardest thing to see is what is in front of your eyes.

If I say to the moment: 'Stay now! You are so beautiful'!

Alas, I have studied philosophy, the law as well as medicine, and to my sorrow, theology; studied them well with ardent zeal, yet here I am, a wretched fool, no wiser than I was before.

Pain and pleasure, good and evil, come to us from unexpected sources. It is not there where we have gathered up our brightest hopes, that the dawn of happiness breaks. It is not there where we have glanced our eye with affright, that we find the deadliest gloom. What should this teach us? To bow to the great and only Source of light, and live humbly and with confiding resignation.

Insofar as he makes use of his healthy senses, man himself is the best and most exact scientific instrument possible. The greatest misfortune of modern physics is that its experiments have been set apart from man, as it were, physics refuses to recognize nature in anything not shown by artificial instruments, and even uses this as a measure of its accomplishments.

Too many parents make life hard for their children by trying, too zealously, to make it easy for them.

First and last, what is demanded of genius is love of truth.