If you go to London now, not everything is beautiful, but it's amazingly better than it was. And the Thames is certainly a lot better: There are fish in the Thames.

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

Scientifically speaking, a butterfly is at least as mysterious as a superstring. When something ceases to be mysterious it ceases to be of absorbing interest to scientists. Almost all things scientists think and dream about are mysterious.

Technology is a gift of God. After the gift of life it is perhaps the greatest of God's gifts. It is the mother of civilizations, of arts and of sciences.

Mathematics is really an art, not a science.

People who travel in China tell me that the mood there is still very upbeat, because their media is different from our media. Chinese media emphasize how well things are going and suppress the bad news and publish the good news.

We have no reason to think that climate change is harmful if you look at the world as a whole. Most places, in fact, are better off being warmer than being colder. And historically, the really bad times for the environment and for people have been the cold periods rather than the warm periods.