Chimps are unbelievably like us - in biological, non-verbal ways. They can be loving and compassionate and yet they have a dark side... 98 per cent of our DNA is the same. The difference is that we have developed language - we can teach about things that aren't there, plan for the future, discuss, share ideas

We can learn to suppress our feelings for other reasons.

Just think of the trust that often exists in soldiers. Within their own unit, you could say they have to trust each other. A spirit of camaraderie builds up and, in the end, they will risk their lives for each other. They may even go so far as to dehumanise the other, enemy group - a mechanism you can also observe in chimps.

I don't have any idea of who or what God is. But I do believe in some great spiritual power. I feel it particularly when I’m out in nature. It’s just something that's bigger and stronger than what I am or what anybody is. I feel it. And it's enough for me.

Words can be said in bitterness and anger, and often there seems to be an element of truth in the nastiness. And words don't go away, they just echo around.

I believe that accurate knowledge is very, very important, but find that out in free time. Don't let it take over every hour of the day. Perhaps most important, talk about it.

Every stage of my life set the scene for the next, and at each point all I had to do was say "yes" and not think too much about the consequences.