“One should not pursue goals that are easily achieved. One must develop an instinct for what one can just barely achieve through one’s greatest efforts.”

“There comes a time when the mind takes a higher plane of knowledge but can never prove how it got there.”

“Communities tend to be guided less than individuals by conscience and a sense of responsibility. How much misery does this fact cause mankind! It is the source of wars and every kind of oppression, which fill the earth with pain, sighs and bitterness.”

“Nothing truly valuable can be achieved except by the unselfish cooperation of many individuals.”

“The tendencies we have mentioned are something new for America. They arose when, under the influence of the two World Wars and the consequent concentration of all forces on a military goal, a predominantly military mentality developed, which with the almost sudden victory became even more accentuated. The characteristic feature of this mentality is that people place the importance of what Bertrand Russell so tellingly terms “naked power” far above all other factors which affect the relations between peoples. The Germans, misled by Bismarck’s successes in particular, underwent just such a transformation of their mentality—in consequence of which they were entirely ruined in less than a hundred years. I must frankly confess that the foreign policy of the United States since the termination of hostilities has reminded me, sometimes irresistibly, of the attitude of Germany under Kaiser Wilhelm II, and I know that, independent of me, this analogy has most painfully occurred to others as well. It is characteristic of the military mentality that non-human factors (atom bombs, strategic bases, weapons of all sorts, the possession of raw materials, etc.) are held essential, while the human being, his desires and thoughts—in short, the psychological factors—are considered as unimportant and secondary. Herein lies a certain resemblance to Marxism, at least insofar as its theoretical side alone is kept in view. The individual is degraded to a mere instrument; he becomes “human materiel.” The normal ends of human aspiration vanish with such a viewpoint. Instead, the military mentality raises “naked power” as a goal in itself—one of the strangest illusions to which men can succumb.”

“I do not believe in the immortality of the individual, and I consider ethics to be an exclusively human concern without any superhuman authority behind it.”

“Brief is this existence, as a visit in a strange house. The path to be pursued is poorly lit by a flickering consciousness.”

“Concern for man and his fate must always form the chief interest of all technical endeavors. Never forget this in the midst of your diagrams and equations.”

“Teaching should be such that what is offered is perceived as a valuable gift and not as hard duty. Never regard study as duty but as the enviable opportunity to learn to know the liberating influence of beauty in the realm of the spirit for your own personal joy and to the profit of the community to which your later work belongs.” 

“What really interests me is whether God had any choice in the creation of the world.”

“Science without religion is lame, religion without science is blind.”

“Life is like riding a bicycle. To keep your balance, you must keep moving.”

“Imagination is more important than knowledge. For knowledge is limited to all we now know and understand, while imagination embraces the entire world, and all there ever will be to know and understand.”

“Nothing happens until something moves.”

“In the matter of physics, the first lessons should contain nothing but what is experimental and interesting to see. A pretty experiment is in itself often more valuable than twenty formulae extracted from our minds.”