Cédric Aubouy, math clown and author of “Je ne sais pas”

Tangente: Your latest book, Je ne sais pas ou la disparition des mathématiciens, came out this summer. What is it about?**

Cédric Aubouy: It is a burlesque journey through the history of mathematics and the birth of computing, from the early 20^th century to the present day. The story rests on the rather outlandish idea that a recursive formula had supposedly been discovered—and kept secret—in order to transform every problem in NP into a problem in P, with the consequences this would have for encryption today (the novel is set in the present). But the narrative also touches on several results in logic, arithmetic, geometry and set theory, along with some entertaining little puzzles. That said—and this matters a great deal to me—readers need no mathematical background whatsoever, and they can easily follow the adventure without necessarily understanding the mathematics they encounter. Of course, I wrote this book to delight maths enthusiasts, but above all I wanted to captivate curious readers wondering where to begin lifting the veil on a world that, from a distance, can seem rather mysterious.

Je ne sais pas is a novel. Why did you choose this form?

Because it lets you enter the realm of the imagination. With L’île logique, my company devoted to burlesque theatre and mathematical clowning, I have written more than ten plays. It is always a pleasure to plunge into absurd worlds before turning to mathematical rigour, so I simply carried on in that vein. Mathematics, for example, has one remarkable advantage over physics: it can break free from reality and sail off into surrealism. The ship’s captain can quite happily be 3,500 years old, and if 17 cakes eat 51 children, each cake will eat three children and all will be well…

Can you explain this intriguing title?

I don’t know… But without giving anything away, let’s say it is a positive feedback loop tied to the story, one that you will understand as you read. And as for the subtitle: AI, something is afoot…

One last, more general question: what does mathematics mean to you?

Oh, that’s a vast question! Without departing from the usual definition involving abstractions, relationships, numbers or points, I would say that mathematics can be approached in three ways: historically, through childhood and in its present-day form. We can view mathematics through the evolution of human thought, from calendar and lunar calculations and notions of exchange or sharing—arithmetical or geometrical—to the contributions of the Chinese, the Greeks, the Arabs and then the West. Or we can see it through a young Homo sapiens’s encounter with the subject: recognizing shapes with an activity cube, for example, then learning to count, infinity slowly coming into view, followed by school—where everything is Euclidean, unlike reality…—and finally the modern practice of mathematics, with the axiomatic method, the presence of computing (constructivist mathematics), and even AI, which is poised to surpass us…

A first glimpse of the burlesque world of Je ne sais pas ---------------------------------------------------------------------

Finishing a good book. The final full stop propels us into an ethereal frustration that stretches through a pensive void. We drift gently, sometimes with a sigh, then sink into an idle languor that makes us want to prolong an impossible moment, cherishing the secret yet futile hope of finding more to read. We listlessly turn to acknowledgements that mean nothing to us, the author’s other titles and even the publisher’s address, before ending up wallowing with ridiculous persistence in the dreary legal deposit notice or, in the worst cases, the barcode. Then, slowly, with the tip of our thumb, we finally release the cardboard back cover, which abruptly closes the book as it opens itself to eyes that have seen it before. We do not want it. Quickly, we turn the book over and reread the title as though we might never have read it; sometimes we even return to the beginning, but we cannot unread it. At last, reluctantly, our thumb sends the pages fluttering past like so many arms rising and whirling to bid the reader one final farewell, and we finally put the book down. Clack. Your coffee, sir, she says, startling the book.

On the bistro’s little round table—wobbly, of course—the cup and the book stare each other down. One has disturbed the other; the small commotion has even brought a few drops of coffee to life, and they have settled down, some on the saucer, some on the table, some on the book. But the waitress walks away. Come to think of it, she looks rather like her cup of coffee: taut and full-bodied, with a knitting needle gleaming like a spoon thrust into the depths of her long black hair, half tied in a bun, above a white corset that seems almost made of earthenware, her tutu skirt forming the saucer. All she lacks is the sugar. And so the book awaits the final caress of its former reader’s kindly forefinger, which might relieve it of the intrusive stain sitting on its cover and drying in the morning sun. There is something beautiful about a waiting book. Perhaps it is waiting for its next reader. A stain taking shape as it dries is beautiful too: it shrinks, takes its time and remains silent, beyond the sounds of the city. Why do our ears have no eyelids?

Ring-ring-ring. Hello, Iyolo? Yes. Hi, it’s Antoine Fraismont. Remember me? Antoine? Good heavens, it’s been an eternity! Funny, I was almost thinking about you just now. What do you mean? Well, I was stirring my coffee, served by a cup, while watching a smudge dry and a book wait, unable to be unread. Didn’t you once study rotating fluids? Yes, yes, the Navier–Stokes equations, of course. I still do, in fact, and I see you’re as much of a dreamer as ever. But that isn’t why I’m calling, Iyolo. This is serious; we need to meet soon, please. After almost twenty years, I assume you don’t want to see me so I can help you finish a crossword! Oh, are you still a crossword solver? A crossword compiler, actually. Yes indeed: enamels, and words, and woes… Sorry? Never mind, I write the way people speak. Where and when do you want to meet, Antoine? Does 9 p.m. at the Macumba suit you? Macumba? Are there still nightclubs called that? Iyolo, the Macumba! Oh yes, sorry, Antoine. How silly of me—I must be losing my memory! Really? Since when? Since when what? You haven’t changed, Iyolo, and that’s a good thing. Thank you, see you tonight, and above all, don’t tell anyone! Sometimes hanging up the phone leaves you just as pensive as finishing a good book. And the stain had dried.

Come here, Faustine. Heel. We’re going to buy you some food. How could this dog be anywhere but at her owner’s feet, given how short the leash is? And yet you weren’t good yesterday. You must wait until I take you out before doing your business! And why, for that matter, do we feel the need to talk to animals as though they were human? Needs. Because we do not speak dog; anthropomorphism, too. We think they understand—then again, who knows, perhaps… But no: this woman in the street simply has no one else to talk to. She lives alone in Paris; her shopping basket shows it, and so do her clothes. So she talks to her dog. She must tell it all her troubles, until one wonders which of them is really at the end of the leash… Iyolo Bourdeilles also knows loneliness. And so, with his read and stained book under his arm, having paid the coffee-stained waitress for his coffee, he watches sympathetically as the old woman enters the grocery shop, thinking that he will put anthropomorphism in his next crossword, with the clue: talks to her dog.

Opening of Cédric Aubouy’s novel Je ne sais pas ou la disparition des mathématiciens (POLE, 2025).

[

](https://www.librairie-infinimath.com/products/je-ne-sais-pas-ou-la-disparition-des-mathematiciens)

order the book here.

Welcome aboard L’île logique ----------------------------

L’île logique is a burlesque theatre and clowning company that brings theoretical science to a wider audience, particularly mathematics (**ilelogique.fr)**.

It offers more than a dozen shows, from preschool through higher education, as well as hands-on theatre-and-maths workshops—notably in preparation for the mathematics component of the Grand oral—scientific concerts, various activities, talks and training courses in mathematics outreach, for example at INSPÉ institutions. Drawing on twenty years of experience throughout France, this Breton company uses imagination and whimsy to foster an appetite for logical and scientific reasoning and awaken a sense of wonder. Combining lucidity with playfulness, L’île logique champions human values while balancing the rigour of critical thought against the absurdity that gives rise to humour.

[