No one knows who wrote the laws of physics or where they come from. Science is based on testable, reproducible evidence, and so far we cannot test the universe before the Big Bang.

The brain weighs only three pounds, yet it is the most complex object in the solar system.

I'm a physicist, and we have something called Moore's Law, which says computer power doubles every 18 months. So every Christmas, we more or less assume that our toys and appliances are more or less twice as powerful as the previous Christmas.

Once confined to fantasy and science fiction, time travel is now simply an engineering problem.

After that cancellation [of the Superconducting Super Collider in Texas, after $2 billion had been spent on it], we physicists learned that we have to sing for our supper. ... The Cold War is over. You can't simply say "Russia!" to Congress, and they whip out their checkbook and say, "How much?" We have to tell the people why this atom-smasher is going to benefit their lives.

What differentiates human from lower-animal consciousness is time. You can't explain the concept of "tomorrow" to your dog. Our consciousness is dominated by time - We're constantly running simulations of the future. Our brain is a prediction machine. The hallmark of intelligence, indeed of genius, is the number and complexity of the feedback loops we use in predicting the future.

A hydrogen bomb, for me, was puny compared to the Big Bang - the creation of the universe. That's what I really wanted to work on - the nature of the universe itself, and that's what I do for a living.