A person who knows all the answers, has an opinion on everything, has a certainty backed up by rational argument, has very little possibility of further progress. Such a person is unlikely to walk away from a discussion with anything more than a reaffirmation of how right he or she has been all along.

I think there is a danger with young people of being dependent in the sense that they don't acquire any identity or self-image of themselves as thinkers.

Only the human brain can deliberately change perceptions, change patterns, invent concepts and tolerate ambiguity.

I do a great deal of work with young children, and if you give a child a problem, he may come up with a highly original solution, because he doesn't have the established route to it.

Humor is by far the most significant activity of the human brain.

I'm in love with this country called "America." I'm a huge fan of America. I'm one of those annoying fans - you know, the ones that read the cd notes and follow you into bathrooms and ask you all kinds of annoying questions about why you didn't live up to that. I'm that kind of fan. I've read the Declaration of Independence, and I've read the Constitution of the United States, and they are some liner notes, dude.

You cannot dig a hole in a different place by digging the same hole deeper