Aging is basically the build-up of error: error at the genetic level, error at the cellular level. Cells normally repair themselves; that's why you heal when you get a cut. But even the mechanism of repair eventually falls apart.

Already from your own cells scientists can grow skin, cartilage, noses, blood vessels, bladders and windpipes. In the future, scientists will grow more complex organs, like livers and kidneys. The phrase 'organ failure' will disappear.

Today, your cell phone has more computer power than all of NASA back in 1969, when it placed two astronauts on the moon. Video games, which consume enormous amounts of computer power to simulate 3-D situations, use more computer power than mainframe computers of the previous decade. The Sony PlayStation of today, which costs $300, has the power of a military supercomputer of 1997, which cost millions of dollars.

It's pointless to have a nice clean desk, because it means you're not doing anything.

I vowed to myself that when I grew up and became a theoretical physicist, in addition to doing research, I would write books that I would have liked to have read as a child. So whenever I write, I imagine myself, as a youth, reading my books, being thrilled by the incredible advances being made in physics and science.

You know; when I look at the night sky and I see this enormous splendor of stars and galaxies, I sometimes ask the question, well how many worlds are we talking about? Well do the math, there are about 100 billion galaxies that are in the visible universe and each galaxy in turn contains about 100 billion stars, you multiply and you get about ten billion trillion stars. Well I think it is the height of arrogance to believe that we are alone in the universe, my attitude is that the universe is teaming, teaming with different kinds of life forms

Think of all the nonsense you had to learn in psychology courses. None of which was testable. None of which was measurable. We had behaviorism, Freudian psychology, all of these theories that you learn in psychology. Totally untestable. Now, we can test it, because physics allows us to calculate energy flows in the brain.