More often there's a compromise between ethics and expediency.

That's a central part of philosophy, of ethics. What do I owe to strangers? What do I owe to my family? What is it to live a good life? Those are questions which we face as individuals.

Of those who die from avoidable, poverty-related causes, nearly 10 million, according to UNICEF, are children under five. They die from diseases such as measles, diarrhoea, and malaria that are easy and inexpensive to treat or prevent.

Each of us spends money on things that we do not really need. You could take the money you're spending on those unnecessary things and give it to this organization the Against Malaria Foundation which would take the money you had given and use it to buy nets to protect children. And we know reliably that if we provide nets, they're used, and they reduce the number of children dying from malaria. Fortunately more and more people are understanding this idea, and the result is a growing movement effective altruism.

The idea that we can actually have an impact on places more or less instantly, too, by responding in some way or not responding, I think, also makes it true.

If it is in our power to prevent something bad from happening, without thereby sacrificing anything of comparable moral importance, we ought, morally, to do it.

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