We come now to the question: what is a priori certain or necessary, respectively in geometry (doctrine of space) or its foundations? Formerly we thought everything; nowadays we think nothing. Already the distance-concept is logically arbitrary; there need be no things that correspond to it, even approximately.

Peace cannot be kept by force. It can only be achieved by understanding. You cannot subjugate a nation forcibly unless you wipe out every man, woman, and child. Unless you wish to use such drastic measures, you must find a way of settling your disputes without resort to arms.

Stand still. The trees ahead and bush beside you are not lost.

A mathematical equation stands forever.

Now to the term 'relativity theory.' I admit that it is unfortunate, and has given occasion to philosophical misunderstandings.

Einstein didn't speak until he was four, leading most of his teachers to believe he was crazy. That is until he whipped out the theory of relativity. BAYUM! Showed you guys.

However we select from nature a complex [of phenomena] using the criterion of simplicity, in no case will its theoretical treatment turn out to be forever appropriate (sufficient).... I do not doubt that the day will come when [general relativity], too, will have to yield to another one, for reasons which at present we do not yet surmise. I believe that this process of deepening theory has no limits.