There has been opposition to experimenting on animals for a long time. This opposition has made little headway because experimenters, backed by commercial firms that profit by supplying laboratory animals and equipment, have been able to convince legislators and the public that opposition comes from uninformed fanatics who consider the interests of animals more important than the interests of human beings.

We see things like reciprocity which are fairly central to our view of ethics. But if you're talking about a set of worked-out rules on what we are supposed to do then, yes, it is a human product.

Bush sees the evil as out there in the wider world, residing in people who 'hate freedom'. Look at his immediate response to the pictures of prisoner abuse; this is not what Americans do, these are not our values.

One thing is certain: you will find plenty of worthwhile things to do. You will not be bored, or lack fulfillment in your life. Most important of all, you will know that you have not lived and died for nothing, because you will have become part of the great tradition of those who have responded to the amount of pain and suffering in the universe by trying to make the world a better place.

So far as this argument is concerned nonhuman animals and infants and retarded humans are in the same category; and if we use this argument to justify experiments on nonhuman animals we have to ask ourselves whether we are also prepared to allow experiments on human infants and retarded adults; and if we make a distinction between animals and these humans, on what basis can we do it, other than a bare-faced - and morally indefensible - preference for members of our own species?

I would like us to think about it more explicitly, and not take our intuitions as the given of ethics, but rather to reflect on it, and be more open about the fact that something is an ethical issues and think what we ought to do about it.

Of all the arguments against voluntary euthanasia, the most influential is the slippery slope: once we allow doctors to kill patients, we will not be able to limit the killing to those who want to die.