Take for example providing a guide dog for a blind person. That's a good thing to do, right? All right. It is a good thing to do. But you have to think what else you could do with the resources. It costs about $40,000 to train a guide dog and train the recipient so that the guide dog can be an effective help to a blind person. It costs somewhere between 20 and $50 to cure a blind person in a developing country if they have trachoma. So you do the sums, and you could provide one guide dog for one blind American or you could cure between 400 and 2,000 people of blindness.

In my world of the people who study war and defense issues, we simply did not talk about robotics. We do not talk about it because it's seen as mere science fiction. It's cold, hard, metallic reality.

Capitalism is very far from a perfect system, but so far we have yet to find anything that clearly does a better job of meeting human needs than a regulated capitalist economy coupled with a welfare and health care system that meets the basic needs of those who do not thrive in the capitalist economy. If we ever do find a better system, I'll be happy to call myself an anti-capitalist.

I'm a Utilitarian, so I don't see the rule against lying as absolute; it's always subject to some overriding utility which may prevent its exercise.

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

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

We need to recognise that what really matters isn't buying more and more consumer goods, but family, friends, and knowing that we are doing something worthwhile with our lives. Helping to reduce the appalling consequences of world poverty should be part of that reassessment.