It is the same with people as it is with riding a bike. Only when moving can one comfortably maintain one's balance.

Everything has changed, except our way of thinking.

Those who have an interest in keeping the machinery of war going will stop at nothing to make public opinion subservient to their murderous ends.

... it is a welcome symptom in an age which is commonly denounced as materialistic, that it makes heroes of men whose goals lie wholly in the intellectual and moral sphere.

But there is another reason for the high repute of mathematics: it is mathematics that offers the exact natural sciences a certain measure of security which, without mathematics, they could not attain.

My opinion about Miller's experiments is the following. ... Should the positive result be confirmed, then the special theory of relativity and with it the general theory of relativity, in its current form, would be invalid. Experimentum summus judex. Only the equivalence of inertia and gravitation would remain, however, they would have to lead to a significantly different theory.

Balance in large measure is knowing the things that can be changed, putting them in proper perspective, and recognizing the things that will not change."