“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)”

“If the facts don't fit the theory, change the facts.”

“That is the way to learn the most, that when you are doing something with such enjoyment that you don’t notice that the time passes”

“Yes, we have to divide up our time like that, between our politics and our equations. But to me our equations are far more important, for politics are only a matter of present concern. A mathematical equation stands forever. ”

“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.”

“In my view, it is the most important function of art and science to awaken this religious feeling and keep it alive in those who are receptive to it.”

“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”

“What is right is not always popular and what is popular is not always right.”

“Man is here for the sake of other men - above all for those upon whose smiles and well-being our own happiness depends.”

“To punish me for my contempt for authority, fate made me an authority myself.”

“Life is sacred, that is to say, it is the supreme value, to which all other values are subordinate.”

“I speak to everyone in the same way, whether he is the garbage man or the president of the university.”

“Three great forces rule the world: stupidity, fear and greed.”

“The idea of a personal God is quite alien to me and seems even naïve.”

“The word 'God' is for me nothing more than the expression and product of human weaknesses, the Bible a collection of honorable, but still primitive legends which are nevertheless pretty childish. No interpretation, no matter how subtle, can (for me) change this.”