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.

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.

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

Had Rumsfeld said at any time 'get me a report on what's going on', he could have had it. You're right, it depends on choices that we make, which parts of the world we want to be in immediate contact with.

The hope of internet anarchists was that repressive governments would have only two options: accept the internet with its limitless possibilities of spreading information, or restrict internet access to the ruling elite and turn your back on the 21st century, as North Korea has done.

Can we really believe that we are living a good life, an ethically decent life if we don't do anything serious to help reduce poverty around the world and help save the lives of children or adults who are likely to die if we don't increase the amount of aid we are giving.

If we can put a man on the moon and sequence the human genome, we should be able to devise something close to a universal digital public library.