If we all think only of our own interests, we are headed for collective disaster - just look at what we are doing to our planet's climate.

In appropriate circumstances we are justified in using humans to achieve goals (or the goal of assisting animals).

The new freedom of expression brought by the Internet goes far beyond politics. People relate to each other in new ways, posing questions about how we should respond to people when all that we know about them is what we have learned through a medium that permits all kinds of anonymity and deception.

I honestly don't know, but if America continues to refuse to reduce its greenhouse gas emissions, I see a bleak future not only for American society, but for the world as a whole. This is a global problem that is not going away, and the United States is an obstacle to solving it.

Why...is the hunter who shoots a deer for venison subject to more criticism than the person who buys a ham at the supermarket? Overall, it is probably the intensively reared pig who has suffered more.

I can tell you that too much money is corrupting American politics. Don't blame the American public. The U.S. Supreme Court has a lot to answer for, because it has made it impossible for Congress to reduce the corrupting influence of money on American political life.

If governments did not mislead their citizens so often, there would be less need for secrecy, and if leaders knew they could not rely on keeping the public in the dark about what they are doing, they would have a powerful incentive to behave better.