The hardest part of returning to a truly healthy environment may be changing the current totally unsustainable heavy-meat-eating culture of increasing numbers of people around the world. But we must try. We must make a start, one by one.

If you do microcredit with men, they tend to quickly drink it. They don't pay you back.

I see that within each human being there are two extremes: there's the loving, the passionate, altruistic side that has evolved with us, and then there's the violent, brutal side that has evolved with us. The question for each individual is: which side is going to come out on top?

Louis [Leakey] was anxious to initiate a scientific study of these chimpanzees. It would be difficult, he emphasized, for nothing was known; there were no guidelines for such a field study; and the habitat was remote and rugged. Dangerous wild animals would be living there, and chimpanzees themselves were considered at least four times stronger than humans. I remember wondering what kind of scientist he would find for such a herculean task.

When you meet these outstanding leaders who have been through a programme that empowers them to take positive action, to make things better for people, for animals and for the environment - when you watch them interact and they start brainstorming, you realise you can relax, because they have got it right. They understand that there's more to this life than just money.

Science demands objective factual evidence - proof; spiritual experience is subjective and leads to faith.

People say, "Oh, we ought to fight for animal rights." We fought for human rights, but even if humans have rights, they can still be horribly abused and are every day. You don't have to go to some far off land, far away place; we have a lot of child abuse in our own society.