I believe with Schopenhauer: We can do what we wish, but we can only wish what we must. Practically, I am, nevertheless, compelled to act as if freedom of the will existed. If I wish to live in a civilized community, I must act as if man is a responsible being. I know that philosophically a murderer is not responsible for his crime; nevertheless, I must protect myself from unpleasant contacts. I may consider him guiltless, but I prefer not to take tea with him.

I am a determinist. As such, I do not believe in free will. The Jews believe in free will. They believe that man shapes his own life. I reject that doctrine philosophically. In that respect, I am not a Jew.

We are inclined to overemphasize the material influences in history. The Russians especially make this mistake. Intellectual values and ethnic influences, tradition and emotional factors are equally important. If this were not the case, Europe would today be a federated state, not a madhouse of nationalism.

In America, more than anywhere else, the individual is lost in the achievements of the many. America is beginning to be the world leader in a scientific investigation. American scholarship is both patient and inspiring. The Americans show an unselfish devotion to science, which is the very opposite of the conventional European view of your countrymen. Too many of us look upon Americans as dollar chasers. This is a cruel libel, even if it is reiterated thoughtlessly by the Americans themselves. It is not true that the dollar is an American fetish. The American student is not interested in dollars, not even in success as such, but in his task, the object of the search. It is his painstaking application to the study of the infinitely little and the infinitely large which accounts for his success in astronomy.

Our time is Gothic in its spirit. Unlike the Renaissance, it is not dominated by a few outstanding personalities. The twentieth century has established the democracy of the intellect. In the republic of art and science, there are many men who take an equally important part in the intellectual movements of our age. It is the epoch rather than the individual that is important. There is no one dominant personality like Galileo or Newton. Even in the nineteenth century, there were still a few giants who outtopped all others. Today the general level is much higher than ever before in the history of the world, but there are few men whose stature immediately sets them apart from all others.

Reading after a certain age diverts the mind too much from its creative pursuits. Any man who reads too much and uses his own brain too little falls into lazy habits of thinking, just as the man who spends too much time in the theater is tempted to be content with living vicariously instead of living his own life.

If I was not a physicist, I would probably be a musician. I often think in music. I live my daydreams in music. I see my life in terms of music. ... I cannot tell if I would have done any creative work of importance in music, but I do know that I get most joy in life out of my violin.

I refuse to make money out of my science. My laurel is not for sale like so many bales of cotton.

Sometimes one pays most for the things one gets for nothing.

No man can visualize four dimensions, except mathematically ... I think in four dimensions, but only abstractly. The human mind can picture these dimensions no more than it can envisage electricity. Nevertheless, they are no less real than electro-magnetism, the force which controls our universe, within, and by which we have our being.