12 Stephen Hawking Quotes Reveal How A Genius Thinks

When he was 21, Stephen Hawking was diagnosed with motor neurone disease.

Doctors told him he had a few years to live.

He's now 72 and one of the foremost physicists alive - a professor at the University of Cambridge, an investigator of black holes, and the author of bestselling book "A Brief History of Time."

Here are a dozen quotes showing Hawking's approach to science and to life.