When the human mind exists in the light of reason and no more than reason, we may say with absolute certainty that Man and all that made him will be in that instant gone.

It is frequently the tragedy of the great artist, as it is of the great scientist, that he frightens the ordinary man.

Each man deciphers from the ancient alphabets of nature only those secrets that his own deeps possess the power to endow with meaning.

It is a commonplace of all religious thought, even the most primitive, that the man seeking visions and insight must go apart from his fellows and love for a time in the wilderness.

It has been said repeatedly that one can never, try as he will, get around to the front of the universe. Man is destined to see only its far side, to realize nature only in retreat.

The journey is difficult, immense. We will travel as far as we can, but we cannot in one lifetime see all that we would like to see or to learn all that we hunger to know.

Of all the unexpected qualities of an unexpected universe, the sheer organizing power of animal and plant metabolism is one of the most remarkable. . . . Where it reaches its highest development, in the human mind, we forget it completely. . . . So important does nature regard this unseen combustion . . . that a starving man's brain will be protected to the last while his body is steadily consumed.