What I am looking for is not out there, it is in me.

So long as the memory of certain beloved friends lives in my heart, I shall say that life is good.

Not the senses I have but what I do with them is my kingdom.

Certainly it is one of our sweetest experiences that when we are touched by some noble affection or pure joy, we remember the dead most tenderly, and feel more powerfully drawn to them.

If I regarded my life from the point of view of the pessimist, I should be undone. I should seek in vain for the light that does not visit my eyes and the music that does not ring in my ears. I should beg night and day and never be satisfied. I should sit apart in awful solitude, a prey to fear and despair. But since I consider it a duty to myself and to others to be happy, I escape a misery worse than any physical deprivation.

The unselfish effort to bring cheer to others will be the beginning of a happier life for ourselves.

Now I feel as if I should succeed in doing something in mathematics, although I cannot see why it is so very important. . . The knowledge doesn't make life any sweeter or happier, does it?