- Let me ask the last, the silliest, or maybe the most important question. What is the meaning of life? What gives your life fulfillment, purpose, happiness, meaning? - From a scientific point of view, the meaning of life is the propagation of DNA, but that's not what I feel. That's not the meaning of my life.

So the meaning of my life is something which is probably different from yours and different from other people's, but we each make our own meaning. So we set up goals. We want to achieve. We want to write a book. We want to do whatever it is we do, write a quartet.

We want to win a football match. And these are short-term goals, well, maybe even quite long-term goals, which are set up by our brains, which have goal-seeking machinery built into them. But what we feel, we don't feel motivated by the desire to pass on our DNA, mostly. We have other goals, which can be very moving, very important.

They could even be called spiritual in some cases. We want to understand the riddle of the universe. We want to understand consciousness. We want to understand how the brain works. These are all noble goals. Some of them can be noble goals anyway. And they are a far cry from the fundamental biological goal, which is the propagation of DNA.

But the machinery that enables us to set up these higher level goals is originally programmed into us by natural selection of DNA. - The propagation of DNA. But what do you make of this unfortunate fact that we are mortal? Do you ponder your own mortality? Does it make you sad?

Does it? - I ponder it. It makes me sad that I shall have to leave and not see what's going to happen next. If there's something frightening about mortality, apart from sort of missing, as I've said, something more deeply, darkly frightening, it's the idea of eternity. But eternity is only frightening if you're there.

Eternity before we were born, billions of years before we were born, and we were effectively dead before we were born. As I think it was Mark Twain said, "I was dead for billions of years before I was born "and never suffered the smallest inconvenience." That's how it's going to be after we leave.

So I think of it as really, eternity is a frightening prospect. And so the best way to spend it is under a general anesthetic, which is what it'll be. - Beautifully put. Richard, it was a huge honor to meet you, to talk to you. Thank you so much for your time.

- Thank you very much. (upbeat music) (upbeat music) (upbeat music) (upbeat music) (upbeat music) (upbeat music)