Honestly, I cannot understand what people mean when they talk about the freedom of the human will. I have a feeling, for instance, that I will something or other; but what relation this has with freedom I cannot understand at all. I feel that I will to light my pipe and I do it; but how can I connect this up with the idea of freedom? What is behind the act of willing to light the pipe? Another act of willing? Schopenhauer once said: Der Mensch kann was er will; er kann aber nicht wollen was er will (Man can do what he will but he cannot will what he wills).

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.