The most beautiful thing we can experience is the mysterious. It is the source of all true art and science. He to whom the emotion is a stranger, who can no longer pause to wonder and stand wrapped in awe, is as good as dead —his eyes are closed. The insight into the mystery of life, coupled though it be with fear, has also given rise to religion. To know what is impenetrable to us really exists, manifesting itself as the highest wisdom and the most radiant beauty, which our dull faculties can comprehend only in their most primitive forms—this knowledge, this feeling is at the center of true religiousness.

Much later questions were raised whether the measurements had been accurate enough to support Einstein's theory. Their readings included the works of Henri Poincaré Ernst Mach and David Hume which influenced his scientific and philosophical outlook. Quantizing these oscillators each level will have an integer occupation number which will be the number of particles in it.

Later with the British philosopher Bertrand Russell Einstein signed the Russell–Einstein Manifesto which highlighted the danger of nuclear weapons. Einstein was in support of defending the Allied forces but largely denounced using the new discovery of nuclear fission as a weapon. Roosevelt that Germany might be developing an atomic weapon and recommended that the U.