Ard: For a physicist like myself, beauty plays a large role in understanding the world. Paul Dirac famously says his fundamental belief was that the world is described in terms of beautiful equations.

DN: Yes.

Ard: For a biologist, is it the same kind of beauty? Or is that beauty metaphor story only really true in physics?

DN: I think it’s universal, but it gets to be interestingly different in different domains of science, it seems to me.

Ard: Okay.

DN: I can understand why a physicist says the equations are beautiful. And if you look at the equations of relativity theory, my goodness are they beautiful! So that kind of beauty I can fully understand.

What seems to me to be the problem is that people then go on to think that that’s the only kind of beauty there can be in science and in hypothesising.

When I found what I thought was a good explanation for the rhythm of the heart, in terms of the interactions between the various protein molecules and the membranes and cell system, I had to say that I had something beautiful there. Of course, it was, as it were, with equations, but actually they were pretty miserable equations: they were differential equations requiring all sorts of initial and boundary conditions. This is not the beauty of the equations of relativity theory! But if you look at it beyond the equations themselves, there is a beauty there that  can happen.

Ard: And so do you think that kind of richer beauty that you’re looking at in this biological system, is that a guide to the truth about the system?

DN: I think when you find that you’ve got that kind of beauty, it is a guide in a similar way, though not operating in quite the same way as happens with seeing a beautiful equation. But it still seems to me to be not a bad guide because you get excited by it, because you really do think you got to, at least, part of the truth.

David: Because it’s beautiful?

DN: Because it’s beautiful in the sense of saying, ‘My goodness, the logic of that is so nice. It has to be like that.’ Now, you might be wrong, of course, and this has to be done with the humility of admitting that one might always be wrong. But it’s hard to avoid that feeling that this is logical. It works because of seeing the logic of how it works. And that, for a scientist, is what makes one appreciate the beauty of it. But it doesn’t have to be the beauty of a very simple equation like E=mc2.

David: But it’s still very odd, though, don’t you think? Why should the human mind find truth to be beautiful? Why should these two things overlap? Don’t you find that strange? I mean, why should that be the case? Why should things that we find beautiful also turn out to be true of the universe?

DN: Yes, it’s like asking the question, ‘How is it that mathematics can be applied to the universe?’

David: Well, it makes it worse.

DN: It makes it worse, precisely.

David: The fact that it does is strange to start with, and then that it’s beautiful as well adds another level of strangeness.

DN: Yes, indeed, and my reaction to that is humility. I’m puzzled