“When you trip over love, it is easy to get up. But when you fall in love, it is impossible to stand again.”

“The development of science and of the creative activities of the spirit requires a freedom that consists in the independence of thought from the restrictions of authoritarian and social prejudice.”

“Gravitation cannot be held responsible for people falling in love. How on earth can you explain in terms of chemistry and physics so important a biological phenomenon as first love? Put your hand on a stove for a minute and it seems like an hour. Sit with that special girl for an hour and it seems like a minute. That's relativity.”

“As far as the laws of mathematics refer to reality, they are not certain; and as far as they are certain, they do not refer to reality.”

“Of what is significant in one's own existence one is hardly aware, and it certainly should not bother the other fellow. What does a fish know about the water in which he swims all his life?”

“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.”

“If I were not a Jew I would be a Quaker.”

“Creating a new theory is not like destroying an old barn and erecting a skyscraper in its place. It is rather like climbing a mountain, gaining new and wider views, discovering unexpected connections between our starting points and its rich environment. But the point from which we started out still exists and can be seen, although it appears smaller and forms a tiny part of our broad view gained by the mastery of the obstacles on our adventurous way up.”

“Of all the communities available to us, there is not one I would want to devote myself to except for the society of the true seekers, which has very few living members at any one time.”

“We know from daily life that we exist for other people first of all, for whose smiles and well-being our own happiness depends.”

“Only the Catholic Church protested against the Hitlerian onslaught on liberty. Up till then I had not been interested in the Church, but today I feel a great admiration for the Church, which alone has had the courage to struggle for spiritual truth and moral liberty”

“Some days you live in pajamas, and your hair kind-of has that Albert Einstein look.”

“A conviction akin to religious feeling of the rationality or intelligibility of the world lies behind all scientific work of a high order.”

“The monotony and solitude of a quiet life stimulates the creative mind.”

“L'interesse per l'uomo in se stesso e per il suo destino deve sempre costituire l'obiettivo primario di tutti gli sforzi compiuti in campo tecnologico [...] affinché le creazioni della nostra mente possano rappresentare un bene e non una maledizione per l'umanità. Non scordatevelo mai, mentre siete alle prese con diagrammi ed equazioni." (dal discorso tenuto nel 1931 agli studenti del California Institute of Technology)”