So why don't we make ourselves the last generation on earth? If we would all agree to have ourselves sterilized then no sacrifices would be required - we could party our way into extinction!

When children see animals in a circus, they learn that animals exist for our amusement. Quite apart from the cruelty involved in training and confining these animals, the whole idea that we should enjoy the humiliating spectacle of an elephant or lion made to perform circus tricks shows a lack of respect for the animals as individuals.

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.

Every profession will have its rogues, of course, no matter what oaths are sworn, but many health care professionals have a real commitment to serving the best interests of their clients.

In the past 20 years alone, it adds up to more death than were caused by all the civil and international wars adn government repression of the entire twentieth century, the century of Hitler and Stalin. How much would we give to prevent those horrors? Yet how little are we doing to prevent today's even larger toll and all the misery that it involves? I believe that if you read this book to the end, and look honestly and carefully at our situation, assessing both the facts and the ethical arguments, you will agree that we must act.

If we are concerned about the exploitation of human workers in countries with low standards of worker protection, we should also be concerned about the treatment of even more defenceless non-human animals.

We don't usually think of what we eat as a matter of ethics. Stealing, lying, hurting people - these acts are obviously relevant to our moral character. In ancient Greece and Rome, ethical choices about food were considered at least as significant as ethical choices about sex.