Science is a way of life. Science is a perspective. Science is the process that takes us from confusion to understanding in a manner that's precise, predictive and reliable - a transformation, for those lucky enough to experience it, that is empowering and emotional.

I believe the process of going from confusion to understanding is a precious, even emotional, experience that can be the foundation of self-confidence.

Science is very good at answering the 'how' questions. 'How did the universe evolve to the form that we see?' But it is woefully inadequate in addressing the 'why' questions. 'Why is there a universe at all?' These are the meaning questions, which many people think religion is particularly good at dealing with.

My view is that science only has something to say about a very particular notion of God, which goes by the name of 'god of the gaps'.

Very much, string theory is simply a work in progress. What we are inching toward every day are predictions that within the realm of current technology we hope to test. It's not like we're working on a theory that is permanently beyond experiment. That would be philosophy.

Intelligence is the ability to take in information from the world and to find patterns in that information that allow you to organize your perceptions and understand the external world.

The bottom line is that time travel is allowed by the laws of physics.

My mom says: 'Why aren't you a doctor?' and I'm like, 'I am a doctor!' and she's all, 'No, I mean a real doctor.' She reads my books, but she says they give her a headache.

In the far, far future, essentially all matter will have returned to energy. But because of the enormous expansion of space, this energy will be spread so thinly that it will hardly ever convert back to even the lightest particles of matter. Instead, a faint mist of light will fall for eternity through an ever colder and quieter cosmos.

Relativity challenges your basic intuitions that you've built up from everyday experience. It says your experience of time is not what you think it is, that time is malleable. Your experience of space is not what you think it is; it can stretch and shrink.

Every moment is as real as every other. Every 'now,' when you say, 'This is the real moment,' is as real as every other 'now' - and therefore all the moments are just out there. Just as every location in space is out there, I think every moment in time is out there, too.

When you buy a jacket, you pick the size to ensure it fits. Similarly, we live in a universe in which the amount of dark energy fits our biological make-up. If the amount of dark energy were substantially different from what we've measured, the environmental conditions would be inhospitable to our form of life.

Nature's patterns sometimes reflect two intertwined features: fundamental physical laws and environmental influences. It's nature's version of nature versus nurture.

My dad was a composer and a musician, but he never finished high school. His formal education was rather minimal from the standards of today's college graduates and Ph.D.'s, but he had a deep interest in questions of science and questions of the universe.