# The QED question

Is a scientific proof a story? Mathematicians Marcus du Sautoy and Sir Roger Penrose attempt to bridge the disciplinary divide with Man Booker laureate Ben Okri and Goldsmith’s Professor of English Literature Laura Marcus.

*By Georgina Ferry*

Is maths about storytelling? Is fiction mathematically rigorous? Those were some of the unusual questions raised during ‘Narrative and Proof’, the opening salvo in a series, Humanities and Science, aimed at demolishing some of the long-standing barriers between the disciplines. The Oxford Research Centre in the Humanities (TORCH), running the series, contends those barriers are an impediment to progress.

Like any cross-cultural marriage, this kind of enterprise sometimes fails through lack of a common language. But on this occasion two cultures almost melted into one as scientists and *literati* (we don’t have a good English word) in turn dissolved some long-established prejudices. The lecture theatre at the Institute of Mathematics in the Radcliffe Observatory Quarter was packed out for the Tuesday 20 January event, and more than a hundred people had to be accommodated in an overflow theatre.

Setting the scene was Marcus du Sautoy (*pictured at the event, left*), holder of chairs in both Mathematics and the Public Understanding of Science. As a mathematician he operates in the abstract realm of number theory. He has also carved out a career as one of our leading science communicators, telling stories about mathematics through books, radio and TV.

He started with a bold conjecture: Narrative *equals* proof. ‘A proof’, he argued, ‘is a travelogue leading from familiar territory to a new land, visible in the distance: like Frodo’s journey from the Shire to Mordor.’ Du Sautoy chose a simple demonstration of a mathematical journey: the proof that the number of primes — numbers that cannot be divided by any other number — is infinite. However many primes you multiply together, if you add 1 to the result you are forced to admit that there must be another. And another, *ad infinitum*.

A proof, for a mathematician, is a route to understanding the surprising ways that numbers behave. The proof in that sense becomes a quest, like the search for the Grail in Arthurian romance. ‘Satisfying proofs have an inevitability about them,’ he said, ‘yet each step cannot be predicted in advance.’

We immediately entered the realm of alternative futures as the Booker prizewinning novelist Ben Okri rose to respond. He’d brought two versions of his talk, one typed, one handwritten. The audience chose the latter, condemning the other to a parallel universe in which Ben Okri might argue from a completely different perspective.

Okri (*pictured right with Sir Roger Penrose*) developed the idea that literary creativity is highly rigorous: stories where ‘anything can happen’ are not good stories. ‘There is an unavoidable logic of storytelling’, said Okri. ‘The equation must work, it must add up, it must compute.’

But Okri saw a distinction between mathematics as intrinsic to the world, implicated in all parts of the universe, ‘not just something mathematicians do’, and narrative as a human endeavour that holds a mirror up to the world: ‘Narration at its highest is about the enigma of being human, alive and conscious. There is no other mechanism by which to examine our existence.’

Mathematical physicist Sir Roger Penrose (recently immortalised on screen in the Hawking biopic *The Theory of Everything*) had trouble elevating narrative to the level of proof — the ‘story’ it told was of no value at all if the proof didn’t actually work. ‘The key thing in maths is that it has to be right’, was his bottom line.

Last to the podium was Professor Laura Marcus, Goldsmith’s Professor of English Literature (*pictured left*), introducing the engagement between the reader and the writer/mathematician. Contemporary literary theory, she pointed out, had taken a ‘cognitive turn’, moving on from structuralism to the interplay between the minds of readers and writers. What were the implications, she wondered, for our understanding of mathematics?

The animated discussion that followed the debate threw up wide-ranging perspectives on the nature of truth, and on the reader’s response. Does the reader respond to literature more subjectively than to maths? For Okri that could be true of a first reading, but he argued that with every reading, subjectivity was stripped away until you had ‘read yourself out’ and understood the work objectively.

Chaired by Elleke Boehmer, novelist and Professor of World Literature in English, the panel consensus was that narrative and proof were not, after all, the same thing. Viewing them simultaneously, however, generated surprising perspectives that kept us all engaged until long after we had left the by-now-familiar lecture theatre and headed for the new landscapes of the after-event buffet or the pub.

* *

*Georgina Ferry, former editor of *Oxford Today*, is a science writer, biographer and broadcaster. Images from the conference © Stuart Bebb, reproduced with kind permission. Background image © Gualtiero Boffi, via Shutterstock.*

## Comments

The title points to a slightly different question; are mathematical proofs scientific ?

My little by's suggestion was that mathematics is like writing a story because in algebra you use letters.

Brilliant topic of course! Our minds work using stories and scripts, so inevitably to understand is to use this very mean of reasoning and interpreting phenomena. In my opinion science or math is

not necessarily narrative though, using scripts and plots is a basic human way of understanding, but not the only one. Many people use computation, visualization, categorization etc. alongside narration to solve problems and to think.