I very rarely think in words at all. A thought comes, and I may try to express in words afterwards.

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.

Those who believe that politics and religion do not mix, understand neither.

Any power must be an enemy of mankind which enslaves the individual by power and by force, whether it arises under the Fascist or the Communist flag. All that is valuable in human society depends upon the opportunity for development accorded to the individual.

The more a country makes military weapons, the more insecure it becomes: if you have weapons, you become a target for attack.

The fact that man produces a concept "I" besides the totality of his mental and emotional experiences or perceptions does not prove that there must be any specific existence behind such a concept. We are succumbing to illusions produced by our self-created language, without reaching a better understanding of anything. Most of so-called philosophy is due to this kind of fallacy.

The ideals which have always shone before me and filled me with the joy of living are goodness, beauty, and truth.