The book unfurls effortlessly, loose and legato. There are no real revelations — the subjects are well known and long dead. There are no stakes; there is no suspense. I was riveted. Olsson is evocative on curiosity as an appetite of the mind, on the pleasure of glutting oneself on knowledge. André “gorges himself” on mathematics and Sanskrit. Simone crawls between her books arrayed on the floor, “leans over Descartes like an animal drinking.”
What’s curious is that we never learn why she was reading Descartes so intently (or that he later became one of her prime philosophical sparring partners). There are slow pans of André at his desk, his cat perched on the edge, but we are rarely privy to the work itself. Olsson remains breezy on the finer points of their intellectual interests, perhaps to keep the narrative from being bogged down.
The glamour of mathematics is what excites her, its colorful stories. The book advances in fragments, historical divagations that drift by, smoothly as clouds: Hippasus of Metapontum supposedly flung off a ship for his discovery of irrational numbers, or the unearthing of the Rhind papyrus of 1700 B.C., one of the oldest mathematical documents, with an insuperable opening line: “Directions for Attaining the Knowledge of All Dark Things.” Olsson is drawn to anecdotes that emphasize the role of beauty and chance. Why do we represent the unknown with x? Credit René Descartes’s printer, who was running out of letters while producing copies of the treatise “La Géométrie.” X, y and z remained, and the printer settled on x, the least used letter in French.
If there is an x in this book, it is Simone Weil.
For all of Olsson’s skill at untangling knotty mathematics, she is baffled by Simone, insensible to her charisma and put off by her prose — “awfully high in fiber,” she describes it, and lacking in style. It is a freakish version of the thinker she offers us, a gaunt catastrophe in wide skirts. “The more I learn,” Olsson writes, “the more I begin to wonder whether his sanity somehow implicated his sister’s extremity, whether in the Weil family, the two roles were divided between them: he would be the great mathematician, and she would come unhinged.”
The issue of Weil’s mental state has long preoccupied and divided her biographers. She died at 34, from tuberculosis, aggravated, it is said, by prolonged malnutrition from restricting herself to children’s wartime rations. “Unhinged” is a crude diagnosis, especially in a book that gives short shrift to her work and influence. From “The Weil Conjectures,” it’s difficult to discern how rich and various her life truly was; or to grasp her political shrewdness and the intellectual concerns and the style that has irrigated the work of Maurice Merleau-Ponty, Iris Murdoch, Giorgio Agamben, Elizabeth Hardwick, Susan Sontag.
The mathematician Henri Poincaré, a mentor to André, imagined that thoughts lived in the mind like static particles, “as if hooked to a wall,” Olsson writes. Thinking liberated them and allowed them to crash into and attach to one another. Her book is full of such moments of connection, combustion and surprise. And if x goes unsolved, there is something apt and beautiful there, too. For all the riddles of mathematics, there is also the ordinary and eternal mystery of other people’s minds.