In exchange for freedom of inquiry, scientists are obliged to explain their work.

And after we returned to the savannahs and abandoned the trees, did we long for those great graceful leaps and ecstatic moments of weightlessness in the shafts of sunlight of the forest roof?

Modern Darwinism makes it abundantly clear that many less ruthless traits, some not always admired by robber barons and Fuhrers - altruism, general intelligence, compassion - may be the key to survival.

Those afraid of the universe as it really is, those who pretend to nonexistent knowledge and envision a Cosmos centered on human beings will prefer the fleeting comforts of superstition. They avoid rather than confront the world. But those with the courage to explore the weave and structure of the Cosmos, even where it differs profoundly from their wishes and prejudices, will penetrate its deepest mysteries.

We are the custodians of life's meaning.

The brain is like a muscle. When it is in use we feel very good. Understanding is joyous.

When we look up at night and view the stars, everything we see is shinning because of distant nuclear fusion.