Hitler didn't travel. Stalin didn't travel. Saddam Hussein never traveled. They didn't want to have their orthodoxy challenged.

A continuing conversation with other persons, with cultural products, and with oneself, is a large part of what it means to be a human being, in our time and perhaps in all time.

Being creative means first of all doing something unusual... On the other hand, however unusual it may be, the idea also has to be reasonable for people to take it seriously.

Fundamentalism is a kind of decision not to change your mind about something...Many of us are fundamentalists...because it worked pretty well for us.

If you think education is expensive, try estimating the cost of ignorance.

The countries who do the best in international comparisons, whether it's Finland or Japan, Denmark or Singapore, do well because they have professional teachers who are respected, and they also have family and community which support learning.

Part of the maturity of the sciences is an appreciation of which questions are best left to other disciplinary approaches.