The worthwhile problems are the ones you can really solve or help solve, the ones you can really contribute something to... No problem is too small or too trivial if we can really do something about it.

Start out understanding religion by saying everything is possibly wrong... As soon as you do that, you start sliding down an edge which is hard to recover from.

Tell your son to stop trying to fill your head with science - for to fill your heart with love is enough!

When you get as old as I am, you start to realize that you've told most of the good stuff you know to other people anyway.

There is no harm in doubt and skepticism, for it is through these that new discoveries are made.

I have a friend who's an artist, and he sometimes takes a view which I don't agree with. He'll hold up a flower and say, "Look how beautiful it is," and I'll agree. But then he'll say, "I, as an artist, can see how beautiful a flower is. But you, as a scientist, take it all apart and it becomes dull." I think he's kind of nutty. [...] There are all kinds of interesting questions that come from a knowledge of science, which only adds to the excitement and mystery and awe of a flower. It only adds. I don't understand how it subtracts.

We never are definitely right, we can only be sure we are wrong.