I always have a high regard for the individual and have an insuperable distaste for violence and clubmanship. All these motives made me into a passionate pacifist and anti-militarist. I am against any nationalism, even in the guise of mere patriotism. Privileges based on position and property have always seemed to me unjust and pernicious, as did any exaggerated personality cult.

What is the meaning of human life, or of organic life altogether? To answer this question at all implies a religion.

The longing to behold this pre-established harmony [of phenomena and theoretical principles] is the source of the inexhaustible patience and perseverance with which Planck has devoted himself ... The state of mind which enables a man to do work of this kind is akin to that of the religious worshiper or the lover; the daily effort comes from no deliberate intention or program, but straight from the heart.

Weakness of attitude becomes weakness of character.

Belief in an external world independent of the perceiving subject is the basis of all natural science.

Nothing that I can do or say will change the structure of the universe. But maybe, by raising my voice, I can help the greatest of all causes — good will among men and peace on earth.

The most superior of scientific goals is to embrace a maximum of experiment with a minimum of hypotheses.