"The vitality of thought is in adventure. Ideas won't keep. Something must be done about them. When the idea is new, its custodians have fervor, live for it, and, if need be, die for it."

“Familiar things happen, and mankind does not bother about them. It requires a very unusual mind to undertake the analysis of the obvious.”

“The Reformation was a popular uprising, and for a century and a half drenched Europe in blood. The beginnings of the Scientific movement were confined to a minority among the intellectual elite.… [T]he worst that happened to men of science was that Galileo suffered an honorable detention and a mild reproof, before dying peacefully in his bed. The way in which the persecution of Galileo has been remembered is a tribute to the quiet commencement of the most intimate change in outlook which the human race had yet encountered. Since a babe was born in a manger, it may be doubted whether so great a thing has happened with so little stir.”

“Men can be provincial in time, as well as in place.”

“Rightness of limitation is essential for growth of reality.Unlimited possibility and abstract creativity can procure nothing. The limitation, and the basis arising from what is already actual, are both of them necessary and interconnected.”

“Life is complex in its expression, involving more than percipience, namely desire, emotion, will, and feeling. ... identification of rhythm as the causal counterpart of life; wherever there is some life, only perceptible to us when the analogies are sufficiently close ... The rhythm is then the life, in the sense in which it can be said to be included within nature.”

“Einstein analyses the ideas of time-order and of simultaneity. Primarily (according to his analysis) time-order only refers to the succession of events at a given place. Accordingly each given place has its own time-order. But these time-orders are not independent in the system of nature, and their correlation is known to us by means of physical measurement. Now ultimately all physical measurement depends upon coincidence in time and place.”