He who finds a thought that lets us a little deeper into the eternal mystery of nature has been granted great peace.

I wouldn't want to live if I did not have my work. In any case, it's good that I'm already old and personally don't have to count on a prolonged future.

I am not only a pacifist but a militant pacifist. I am willing to fight for peace. Nothing will end war unless the people themselves refuse to go to war.

We must dedicate our lives to drying up the source of war: ammunition factories.

Live life to the fullest. You have to color outside the lines once in a while if you want to make your life a masterpiece. Laugh some every day. Keep growing, keep dreaming, keep following your heart. The important thing is not to stop questioning.

If I give you a pfennig, you will be one pfennig richer and I'll be one pfennig poorer. But if I give you an idea, you will have a new idea, but I shall still have it too.

There is, however, one other human right which is infrequently mentioned but which seems to be destined to become very important: this is the right, or the duty, of the individual to abstain from cooperating in activities which he considers wrong or pernicious.