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.

I am not saying that factory farming is the same as the Holocaust or the slave trade, but it's clear that there is an immense amount of suffering in it, and just as we think that the Nazis were wrong to ignore the suffering of their victims, so we are wrong to ignore the sufferings of our victims.

Do business managers have a commitment to anything more than the success of their company and to making money? It would be hard to say that they do. Indeed, many business leaders deny that there is any conflict between self-interest and the interests of all.

Knowing that we can control our own behaviour makes it more likely that we will.

But I think the majority of cows, and even more so chickens and pigs, are leading pretty miserable lives.

The new freedom of expression brought by the Internet goes far beyond politics. People relate to each other in new ways, posing questions about how we should respond to people when all that we know about them is what we have learned through a medium that permits all kinds of anonymity and deception.

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.