“The generalized theory of relativity has furnished still more remarkable results. This considers not only uniform but also accelerated motion. In particular, it is based on the impossibility of distinguishing an acceleration from the gravitation or other force which produces it. Three consequences of the theory may be mentioned of which two have been confirmed while the third is still on trial: (1) It gives a correct explanation of the residual motion of forty-three seconds of arc per century of the perihelion of Mercury. (2) It predicts the deviation which a ray of light from a star should experience on passing near a large gravitating body, the sun, namely, 1".7. On Newton's corpuscular theory this should be only half as great. As a result of the measurements of the photographs of the eclipse of 1921 the number found was much nearer to the prediction of Einstein, and was inversely proportional to the distance from the center of the sun, in further confirmation of the theory. (3) The theory predicts a displacement of the solar spectral lines, and it seems that this prediction is also verified.”

“I cannot imagine a God who rewards and punishes the objects of his creation, whose purposes are modeled after our own -- a God, in short, who is but a reflection of human frailty. Neither can I believe that the individual survives the death of his body, although feeble souls harbor such thoughts through fear or ridiculous egotisms.”

“The person who reads too much and uses his brain too little will fall into lazy habits of thinking..”

“When you change the way you look at things, the things you look at change.”

“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 am satisfied with the mystery of the eternity of life and with the awareness and a glimpse of the marvelous structure of the existing world, together with the devoted striving to comprehend a portion, be it ever so tiny, of the Reason that manifests itself in nature.”

“Numerous are the academic chairs, but rare are wise and noble teachers. Numerous and large are the lecture halls, but far from numerous the young people who genuinely thirst for truth and justice. Numerous are the wares that nature produces by the dozen, but her choice products are few. We all know that, so why complain? Was it not always thus and will it not always thus remain? Certainly, and one must take what nature gives as one finds it. But there is also such a thing as a spirit of the times, an attitude of mind characteristic of a particular generation, which is passed on from individual to individual and gives its distinctive mark to a society. Each of us has to his little bit toward transforming this spirit of the times.” 

“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)”

“Just because you don't believe in something doesn't mean it isn't true.”

“I believe in intuitions and inspirations...I sometimes FEEL that I am right. I do not KNOW that I am.”

“You do not really understand something unless you can explain it to your grandmother.”

“There is far too great a disproportion between what one is and what others think one is, or at least what they say they think one is.”

“The world as we have created it is a process of our thinking. It cannot be changed without changing our thinking.”

“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.” 

Equations are more important to me, because politics is for the present, but an equation is something for eternity.”