At the descriptive level, certainly, you would expect different cultures to develop different sorts of ethics and obviously they have; that doesn't mean that you can't think of overarching ethical principles you would want people to follow in all kinds of places.

I am not saying that factory farming is the same as the Holocaust or the slave trade, but it's clear that there is an immense amount of suffering in it, and just as we think that the Nazis were wrong to ignore the suffering of their victims, so we are wrong to ignore the sufferings of our victims.

I suppose what's happened recently has confirmed suspicions I voiced in the book, and I think made clearer some of those things that I point out. For instance I have a section of the book where I talk about the possibility of torture.

I'm not overly alarmist about it, but I do think there are some worrying signs, like the growing accumulation of wealth by a very small proportion of the population, plus elections in the US are much more dominated by money than anywhere else calling itself a democracy.

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.

Sci-fi is often a metaphor. I think it's more the themes and questions that science fiction raises rather than the exact predictions that should guide us.

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

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.

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