Of course, long-distance running has to do with the fact that we're hunters.

A good cause can become bad if we fight for it with means that are indiscriminately murderous. A bad cause can become good if enough people fight for it in a spirit of comradeship and self-sacrifice. In the end it is how you fight, as much as why you fight, that makes your cause good or bad.

There is no doubt that parts of the world are getting warmer, but the warming is not global.

It's not going to be just humans colonizing space, it's going to be life moving out from the Earth, moving it into its kingdom. And the kingdom of life, of course, is going to be the universe.

The more I examine the universe and study the details of its architecture, the more evidence I find that the universe in some sense must have known that we were coming.

Everything in my life was luck. The key to having an interesting life is to always say "yes" to anything crazy.

I think it's much better to have your eyes open, but on the other hand, of course it can do harm if you tell people look, there's all these terrible things you can do and then some idiot may go ahead and do it.