The most fundamental question we can ever ask ourselves is whether or not the universe we live in is friendly or hostile.
In the middle of every difficulty lies opportunity.
Imagination is greater than knowledge.
Education is not received. It is achieved.
I see in Nature a magnificent structure... that must fill a thinking person with a feeling of humility.
Human beings, in their thinking, feeling and acting are not free agents but are as causally bound as the stars in their motion.