“I don't pretend to understand the universe — it's much bigger than I am.”

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

“The development from a religion of fear to moral religion is a great step in peoples' lives.”

“We all know that light travels faster than sound. That's why certain people appear bright until you hear them speak.”

“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.”

“But science can only be created by those who are thoroughly imbued with the aspiration toward truth and understanding. This source of feeling, however, springs from the sphere of religion. To this there also belongs the faith in the possibility that the regulations valid for the world of existence are rational, that is, comprehensible to reason. I cannot conceive of a genuine scientist without that profound faith. The situation may be expressed by an image: science without religion is lame, religion without science is blind.”

“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)”

“This is a question too difficult for a mathematician. It should be asked of a philosopher"(when asked about completing his income tax form)”

“When the number of factors coming into play in a phenomenological complex is too large scientific method in most cases fails. One need only think of the weather, in which case the prediction even for a few days ahead is impossible.”

“In the temple of science are many mansions, and various indeed are they that dwell therein and the motives that have led them thither. Many take to science out of a joyful sense of superior intellectual power; science is their own special sport to which they look for vivid experience and the satisfaction of ambition; many others are to be found in the temple who have offered the products of their brains on this altar for purely utilitarian purposes. Were [someone to] drive all the people belonging to these two categories out of the temple, the assemblage would be seriously depleted, but there would still be some men, of both present and past times, left inside. Our Planck is one of them, and that is why we love him.”

“You cannot simultaneously prevent and prepare for war.”

“If a cluttered desk is a sign of a cluttered mind, of what, then, is an empty desk a sign?”

“I have deep faith that the principle of the universe will be beautiful and simple.”

“Nella vita quotidiana sono il classico solitario, ma la consapevolezza di appartenere alla comunità invisibile di quelli che lottano per la verità, per la bellezza e per la giustizia mi ha risparmiato ogni sensazione di isolamento”

“satu-satunya yang pasti adalah ketidakpastian ”