I'd much rather be part of a society which greatly honors and respects people who are altruists and who are effective in their altruism, than one that either admires people because they're, you know, celebrity movie stars or because they're super wealthy just no matter what they do with their wealth because I think we ought to try to encourage more people to act in that way.

In a situation where many national leaders do the same thing and look out for national interests, and with an issue like global warming, you're likely to get no solution, so I think you have to have some kind of ethical trump on some of those issues.

Take for example providing a guide dog for a blind person. That's a good thing to do, right? All right. It is a good thing to do. But you have to think what else you could do with the resources. It costs about $40,000 to train a guide dog and train the recipient so that the guide dog can be an effective help to a blind person. It costs somewhere between 20 and $50 to cure a blind person in a developing country if they have trachoma. So you do the sums, and you could provide one guide dog for one blind American or you could cure between 400 and 2,000 people of blindness.

Sometimes animals may suffer more because of their more limited understanding. If, for instance, we are taking prisoners in wartime we can explain to them that although they must submit to capture, search, and confinement, they will not otherwise be harmed and will be set free at the conclusion of hostilities. If we capture wild animals, however, we cannot explain that we are not threatening their lives. A wild animal cannot distinguish an attempt to overpower and confine from an attempt to kill; the one causes as much terror as the other.

If a being suffers there can be no moral justification for refusing to take that suffering into consideration. No matter what the nature of the being, the principle of equality requires that its suffering be counted equally with the like suffering - insofar as rough comparisons can be made - of any other being. So the limit of sentience is the only defensible boundary of concern for the interests of others. To mark this boundary by some other characteristic like intelligence or rationality would be to mark it in an arbitrary manner. Why not choose some other characteristic, like skin color?

Today, if you have an Internet connection, you have at your fingertips an amount of information previously available only to those with access to the world's greatest libraries - indeed, in most respects what is available through the Internet dwarfs those libraries, and it is incomparably easier to find what you need.

Extreme poverty is not only a condition of unsatisfied material needs. It is often accompanied by a degrading state of powerlessness.