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

There is a growing movement called effective altruism. It's important because it combines both the heart and the head.

I believe that nationalism is a very strong force, but there are other forces operating; there are tendencies pushing towards a larger picture, especially in Europe, I think; but I still think nationalism is real.

People tend to care about dogs because they generally have more experience with dogs as companions; but other animals are as capable of suffering as dogs are. Few people feel sympathy for rats. Yet rats are intelligent animals, and there can be no doubt that rats are capable of suffering and do suffer from countless painful experiments performed on them. If the army were to stop experiments on dogs and switch to rats instead, we should not be any less concerned.

Whatever the reason, for most of the present century, the literature and publicity of the old established [animal welfare] groups made a significant contribution to the prevailing attitude that dogs and cats and wild animals need protection, but other animals do not. Thus people came to think of "animal welfare" as something for kindly ladies who are dotty about cats, and not as a cause founded on basic principles of justice and morality.

It is an indication of the extent to which people are now isolated from the animals they eat that children brought up on storybooks that lead them to think of a farm as a place where animals wander around freely in idyllic conditions might be able to live out their entire lives without ever being forced to revise this rosy image.

Looking back on my career, I think I've been extremely fortunate to be in the right place at the right time in order to have the influence that I did.