If it is in our power to prevent something bad from happening, without thereby sacrificing anything of comparable moral importance, we ought, morally, to do it.

In some parts of the world, what you are doing is already apparent.According to the World Health Organization, the warming of the planet caused an additional 140,000 deaths in 2004, as compared with the number of deaths there would have been had average global temperatures remained as they were during the period 1961 to 1990. This means that climate change is already causing, every week, as many deaths as occured in the terrorist attacks on September 11, 2001.

There are some circumstances, for example, where the newborn baby is severely disabled and where the parents think that it's better that child should not live, when killing the newborn baby is not at all wrong ... not like killing the chimpanzee would be.

We certainly would resolve the problems of the charities that are working in areas where they can do the most good. So if you consider that the U.S. foreign aid budget is 30 billion, yes, we could make a major contribution to reducing global poverty, start to deal much better with some of the other big environmental problems that the world faces. So I think we could solve a lot of problems.

There is an obvious evolutionary explanation for the scarcity of altruistic saints: Without a strong predilection for their own interests, our ancestors would have been unlikely to survive, reproduce, and give their own offspring a chance of doing the same. Now conditions have changed and for most of us, surviving and reproducing isn't such a struggle but we still carry the genes of our ancestors and they influence - not determine, but influence - our behavior.

The animal liberation movement is saying that where animals and humans have similar interests - we might take the interest in avoiding physical pain as an example, for it is an interest that humans clearly share with other animals - those interests are to be counted equally, with no automatic discount just because one of the beings is not human.

We are not especially 'interested in' animals. Neither of us had ever been inordinately fond of dogs, cats, or horses in the way that many people are. We didn't 'love' animals.