This is a delightful and engaging conversation between these two extraordinary thinkers (audio only). Natural selection is the focus, but there is a lot more, including scientific revolutions and fractal animals. Here’s an excerpt from the 18-minute conversation:

Can you remember the moment you decided to become a scientist?

RD: I only became fired up in my second year of a science degree. Unlike you, I was never a boy naturalist, to my regret. It was more the intellectual, philosophical questions that interested me.

DA: I am a naturalist rather than a scientist. Simply looking at a flower or a frog has always seemed to me to be just about the most interesting thing there is. Others say human beings are pretty interesting, which they are, but as a child you’re not interested in Auntie Flo’s psychology; you’re interested in how a dragonfly larva turns into a dragonfly.

RD: Yes, it’s carrying inside it two entirely separate blueprints, two different programmes.

DA: I couldn’t believe it! I remember asking an adult, “What goes on inside a cocoon?” and he said, “The caterpillar is totally broken down into a kind of soup. And then it starts again.” And I remember saying, “That can’t be right.” As a procedure, you can’t imagine how it evolved.

If you stay around until the end of the discussion, you’ll get to hear Attenborough imitating Ernst Mayr.