If you look at history, even recent history, you see that there is indeed progress. . . . Over time, the cycle is clearly, generally upwards. And it doesn't happen by laws of nature. And it doesn't happen by social laws. . . . It happens as a result of hard work by dedicated people who are willing to look at problems honestly, to look at them without illusions, and to go to work chipping away at them, with no guarantee of success — in fact, with a need for a rather high tolerance for failure along the way, and plenty of disappointments.

A lot of the letters that are coming in - a lot of them are queries or comments - are one sentence long... These are from Twitter. And if you look at the nature of those one sentence letters, most of the time it's something that came to somebody's mind - somebody walking down the street had a thought and sent it out. If they thought about it for two minutes they would not have sent it.

If you want to become a biologist, it doesn't help to go into the Harvard biology library and all the information is there for you. You have to know what to look for and the internet is the same, just magnified.

What matters is the way we Americans think about ourselves. We think about ourselves as incapable of committing crimes. Everything we do, we make a lot of errors, you know, you can't help it. Mistakes all over the place, but out of naïveté or, you know, misplaced kindness or something like that.

It also seems beyond controversy that moral responsibilities are greater to the extent that people "have the resources, the training, the facilities and opportunities to speak and act effectively."

The whole infrastructure of air travel was, and is, part of government policy. It is not a natural development of a free economic system - at least not in the way that is claimed. The same is true of the roads, of course.

Nothing is more inspiring to see how poor and suffering people, living under conditions incomparably worse than we endure, continue quietly and unpretentiously with courageous and committed struggle for justice and dignity.