Flowery Regions of Algebra

Simon Schaffer

• Pierre Simon Laplace 1749-1827: A Determined Scientist by Roger Hahn
  Harvard, 310 pp, £21.95, November 2005, ISBN 0 674 01892 3

There were fears of revolutionary violence in Paris in the spring of 1773. The police tried to quell the disturbances and make those responsible account for their actions, but they had no success. The trouble spread, first downriver to Normandy, then elsewhere. Statements in the newspapers designed to assuage fears and explain the source of the trouble had little effect, and the crisis lasted well into the summer. The cause of all the bother was some arcane speculation on the chances of comets crashing into the Earth. Journalists grumbled that future Frenchmen would be amused by the tale of ignorant citizens disordered by a mere astronomical calculation. Voltaire joined in, mocking Parisians who’d fled the city to escape the cometary apocalypse: they ‘aren’t philosophers and, if you believe what they believe, don’t have enough time left to turn into philosophers’. The Académie Royale des Sciences had inadvertently started the panic by announcing a talk on comet collisions and their possible hazards. To restore calm, a committee was organised, the evidence reviewed, and an announcement put out to the effect that the chance of a crash was 1:64,000. The sums did not soothe Parisian nerves. ‘The vulgar, ignorant and timid, having no other reason to reassure themselves about rather unusual phenomena but the example and authority of enlightened people, become alarmed very easily,’ the committee concluded.