Were we incapable of empathy – of putting ourselves in the position of others and seeing that their suffering is like our own – then ethical reasoning would lead nowhere. If emotion without reason is blind, then reason without emotion is impotent.

Grain that is used to feed animals that end up on our tables as turkeys and hams could have gone to feed starving people.

If we all think only of our own interests, we are headed for collective disaster - just look at what we are doing to our planet's climate.

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.

Sometimes we know the best thing to do, but fail to do it. New year's resolutions are often like that. We make resolutions because we know it would be better for us to lose weight, or get fit, or spend more time with our children. The problem is that a resolution is generally easier to break than it is to keep.

As we realize that more and more things have global impact, I think we're going to get people increasingly wanting to get away from a purely national interest.

I don't think nationalism is alone holding the field; it's in contention with a lot of different things.