The most important thing is to actually think about what you do. To become aware and actually think about the effect of what you do on the environment and on society. That's key, and that underlies everything else.

What makes us human, I think, is an ability to ask questions, a consequence of our sophisticated spoken language.

I think we're still in a muddle with our language, because once you get words and a spoken language it gets harder to communicate.

I urge you to read Eternal Treblinka and think deeply about its important message.

The chimpanzee study was - well, it's still going on, and I think it's taught us perhaps more than anything else to be a little humble; that we are, indeed, unique primates, we humans, but we're simply not as different from the rest of the animal kingdom as we used to think.

It has actually been suggested that warfare may have been the principle evolutionary pressure that created the huge gap between the human brain and that of our closest living relatives, the anthropoid apes. Whole groups of hominids with inferior brains could not win wars and were therefore exterminated.