I have remained a simple fellow who asks nothing of the world; only my youth is gone - the enchanting youth that forever walks on air.

I no longer believed in the known God of the Bible, but rather in the mysterious God expressed in nature.

Man, surrounded by facts, permitting himself no surprise, no intuitive flash, no great hypothesis, no risk, is in a locked cell. Ignorance cannot seal the mind and imagination more securely.

Everybody should be ashamed who uses the wonders of science and engineering without thinking and having mentally realized not more of it than a cow realizes of the botany of the plants which it eats with pleasure.

A theory is something nobody believes, except the person who made it. An experiment is something everybody believes, except the person who made it.

Any society which does not insist upon respect for all life must necessarily decay.

Every age has its beautiful moments.