We should give the same respect to the lives of animals as we do to the lives of humans.

Becoming a vegetarian is not merely a symbolic gesture. Nor is it an attempt to isolate oneself from the ugly realities of the world, to keep oneself pure and so without responsibility for the cruelty and carnage all around. Becoming a vegetarian is a highly practical and effective step one can take toward ending both the killing of nonhuman animals and the infliction of suffering on them.

If zoos are like arks, then rare animals are like passengers on a voyage of the damned, never to find a port that will let them dock or a land in which they can live in peace. The real solution, of course, is to preserve the wild nature that created these animals and has the power to sustain them. But if it is really true that we are inevitably moving towards a world in which mountain gorillas can survive only in zoos, then we must ask whether it is really better for them to live in artificial environments of our design than not to be born at all.

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.

Were we incapable of empathy – of putting ourselves in the position of others and seeing that their suffering is like our own – then ethical reasoning would lead nowhere. If emotion without reason is blind, then reason without emotion is impotent.

Killing a defective infant is not morally equivalent to killing a person. Sometimes it is not wrong at all.

In the sense that you're not at the centre of power, like a president or prime minister of a major power, everyone is marginalised; my position doesn't isn't unique in that respect. I think there are different sorts of relevance in different contexts.