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.

They come into being not through demonstration but through revelation, through the medium of powerful personalities.

Time has no independent existence apart from the order of events by which we measure it.

I don't try to imagine a personal God; it suffices to stand in awe at the structure of the world, insofar as it allows our inadequate senses to appreciate it.

Thinking is to man what flying is to birds. Don’t follow the example of a chicken when you could be a lark.

During the last century, and part of the one before, it was widely held that there was an unreconcilable conflict between knowledge and belief.

I like to experience the universe as one harmonious whole. Every cell has life. Matter, too, has life; it is energy solidified. Our bodies are like prisons, and I look forward to be free, but I don't speculate on what will happen to me. I live here now, and my responsibility is in this world now.