... mathematics ... affords the exact natural sciences a certain measure of certainty, to which without mathematics they could not attain.

It is an outcome of faith that nature-as she is perceptible to our five senses-takes the character of such a well formulated puzzle.

My pacifism is not based on any intellectual theory but on a deep antipathy to every form of cruelty and hatred.

... a person who is religiously enlightened appears to me to be one who has, to the best of his ability, liberated himself from the fetters of his selfish desires and is preoccupied with thoughts, feelings, and aspirations to which he clings because of their superpersonal value.

I think and think for months and years. Ninety-nine times, the conclusion is false. The hundredth time I am right.

As to science, we may well define it for our purpose as "methodical thinking directed toward finding regulative connections between our sensual experiences."

Concern for man himself and his fate must always form the chief interest of all technical endeavors, concern for the great unsolved problems of the organization of labor and the distribution of goods-in order that the creations of our mind shall be a blessing and not a curse to mankind. Never forget this in the midst of your diagrams and equations.

Science can only ascertain what is, but not what should be, and outside of its domain value judgments of all kinds remain necessary.

The grand aim of all science is to cover the greatest number of empirical facts by logical deduction from the smallest number of hypotheses.

The scientist finds his reward in what Henri Poincare calls the joy of comprehension, and not in the possibilities of application to which any discovery may lead.