I am strongly drawn to a frugal life and am often oppressively aware that I am engrossing an undue amount of the labor of my fellow men.

Fantasie is belangrijker dan kennis, want kennis is begrensd.

Pure mathematics is, in its way, the poetry of logical ideas.

Common sense is nothing more than a deposit of prejudices laid down by the mind before you reach eighteen.

Either CS (coordinate system) could be used with equal justification. The two sentences: the sun is at rest and the earth moves, or the sun moves and the earth is at rest, would simply mean two different conventions concerning two different CS

Our situation on this earth seems strange. Every one of us appears here involuntarily and uninvited for a short stay, without knowing the whys and the wherefore. In our daily lives we only feel that man is here for the sake of others, for those whom we love and for many other beings whose fate is connected with our own. I am often worried at the thought that my life is based to such a large extent on the work of my fellow human beings and I am aware of my great indebtedness to them.

You believe in the God who plays dice, and I in complete law and order in a world that objectively exists, and which I, in a wildly speculative way, am trying to capture. ... Even the great initial success of the quantum theory does not make me believe in the fundamental dice-game, although I am well aware that our younger colleagues interpret this as a consequence of senility. No doubt the day will come when we will see whose instinctive attitude was the correct one.