I meet so many people who are intimidated by arithmetic.

Our goal in science is to discover universal laws of nature. That pursuit fills me with wonder.

I often reflect on what an extraordinary time (pun intended) it is to be alive here in the beginning of the twenty-first century. It took life billions of years to get to this point. It took humans thousands of years to piece together a meaningful understanding of our cosmos, our planet and ourselves. Think how fortunate we are to know this much. But think also of all that's yet to be discovered. Here's hoping the deep answers to the deep questions-from the nature of consciousness to the origin of life-will be found in not too much more time.

Not wasting any water bottles is good. Not leaving the lights on is good. Turning the thermostat down in the winter, up in the summer, is good. But the best thing any of us in the developed world, especially in the United States, can be doing is talking about it.

Intuitively you want some place [such as your phone] to store phone numbers, so you have that part of your brain to do other tasks.

The oncoming trouble I speak of is climate change. It's going to affect all of you in the same way the Second World War consumed people of my parent's generation.

Evolution is a theory, and it's a theory that you can test. We've tested evolution in many ways. You can't present good evidence that says evolution is not a fact.