The natural scientists of the previous age knew less than we do and believed they were very close to the goal: we have taken very great steps in its direction and now discover we are still very far away from it. With the most rational philosophers an increase in their knowledge is always attended by an increased conviction of their ignorance.

There is a great difference between believing in something and believing in it again.

It is astonishing how much the word infinitely is misused: everything is infinitely more beautiful, infinitely better, etc. The concept must have something pleasing about it, or its misuse could not have become so general.

Nothing makes one old so quickly as the ever-present thought that one is growing older.

There is something in our minds like sunshine and the weather, which is not under our control. When I write, the best things come to me from I know not where.

Just as there are polysyllabic words that say very little, so there are also monosyllabic words of infinite meaning.

One should never trust a person who, while assuring you of something, puts his hands on his heart.