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The Parrot’s Theorem
by Denis Guedj
translated by Frank Wynne

This book is French. Of course it is. Where else would a novel quite overtly written as a vehicle for telling the history of mathematics become an immediate bestseller? Where else except in a country where dinner fills the evening and conversation fills dinner-time. Conversation that turns into excitement over the story of maths.


Guedj wraps his lessons in a mystery. What happened to the old mathematician who lived in a Brazilian forest and suddenly sent his entire library to a friend he had not seen in half a century? Guedj people’s his audience with quirky, if not deeply realized, characters. It’s not you and me attending lectures on squaring the circle. It’s deaf eleven-year-old, Max, who has come home from the flea market with a parrot he’s rescued from smugglers. It’s argumentative twin seventeen-year-olds and their hard-working mother. It’s a taxi-driver who only takes people from the airport if they’ve arrived from a city he wants to hear about: “Cities, mind you, not countries. Countries only exist on maps, but cities…cities are real places.”


And these people live in Paris. What’s not to like about a novel set in Paris? I would read it just for the street names: ‘The rue Ravignan is short and steep, running from the fountain at the Place Èmile-Goudeau , where the Bateau-Lavoir – Montmartre’s famous studio of painters – still stands, to the junction of the rue des Abbesses and the rue d’Orchampt.’


Mr. Ruche owns a bookshop on the rue d’Orchampt, called A Thousand and One Pages. He’s a philosopher by education. Talking about the library of Alexandria he says,

“The first manuscripts were kept in rolls – in Latin, volumen, hence the word volume.”

            “Where would you be without etymology?” (says one of those highly articulate twins.)

            “I think I might find words a little less interesting.”

It’s Mr. Ruche who takes delivery of a lorry-load of crates filled with books on mathematics.


Mr. Ruche sleeps in a converted garage in the courtyard of his house, because he has turned over the living area above his shop to his assistant, Perrette, her twins, Jonathan and Lea and her son Max. They live together as one unusual, but very French, family. Mr. Ruche is making osso bucco for dinner and talking to Lea:

‘Mr. Ruche lifted the lids of the pans in turn: the veal was cooking in the frying pan and the shallots softening in the saucepan.

            “You can argue successfully only if you are agreed on the basis for the argument. Once that is agreed, you can discuss the rest. I say something, you respond. I make a point, you argue the point, you refine your argument, I shift my ground.”

Do they really behave like that in French families? Do teenagers join in conversations like that? In some families they certainly do. I’ve been at dinner tables where they do.


In the Grand Palais, off the Champs-Élysées, there is a science museum and in the science museum there is a ‘Temple to p’. Around the frieze of this room, p is written out to 707 decimal places. Naturally Guedj’s characters find themselves craning their necks:

            ‘As they filed out everyone looked up and read:

It was beautifully simple, true – but was it beautiful? Mr. Ruche studied it. Five symbols. p; the equals symbol, which Recorde had invented; -1, which reminded Mr. Ruche of descending a multi-storey car park; i for imaginary, which Euler invented himself. Then there was the e, which he had seen for the first time that morning.

            “Do you think it’s beautiful?” he asked Max.

            “I dunno…beauty is in the eye of the beholder.”’


And the parrot? The parrot is part of the mystery plot. I’ve told you a lot about the book but very little about the plot. It’s a mystery. I don’t want to spoil it. Suffice it to say for now that Max loves the parrot:

            ‘At eleven years old, Max knew a bargain when he saw one and always came back from the market with something strange and valuable. This time it had feathers, and it stank.’

But by the end of the book:

            ‘Mr. Ruche recalled Plato’s definition of a mathematician “ A birdman in an aviary, capturing birds of brilliant colours.”


This is not a great work of literature. There is much to criticize in the writing style and the plotting but if you love Paris, if you have an affection for things French, if you think you might just enjoy finding out a little something about the history of mathematics, The Parrot’s Theorem is for you.


Photo is author's own

One thing about this cover: the young boy could easily be Max but that is definitely not the parrot described in the text. Cover artist failing or a comment on the way appearances are not always as they seem, even in mathematics?

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