G. H. Hardy boasted his mathematics was useless; physics and cryptography disagree
Hardy, the Cambridge purist who discovered Ramanujan, took pride in never having done anything useful. Yet his formula with Ramanujan for counting integer partitions helps physicists describe atomic nuclei, his number theory matters in cryptography, and a five-minute favour to a cricket partner produced a founding law of population genetics.
Born in 1877 in Cranleigh, Surrey, to schoolteacher parents, Hardy showed his bent early: at two he wrote numbers into the millions, and in church he factorised hymn numbers. At Trinity College, Cambridge, he nearly switched to history until a tutor steered him to Camille Jordan's Cours d'analyse, which first showed him what mathematics really meant. He later helped import that continental rigour into British mathematics, which had long clung to Newton's applied tradition, and campaigned against the Tripos exam system.
In January 1913 a letter arrived from Srinivasa Ramanujan, an untrained clerk in India. Hardy at first suspected a hoax, then decided by evening that such a skilful fraud was less likely than genius, and brought Ramanujan to Cambridge. He called their partnership the one romantic incident of his life and, asked by the young Paul Erdős for his greatest contribution, named the discovery of Ramanujan. On his own scale of talent he scored himself 25 and Ramanujan 100.
His other great partnership, with John Edensor Littlewood from 1911, produced the Hardy-Littlewood circle method and famous conjectures on primes. A colleague joked that England had three great mathematicians: Hardy, Littlewood and Hardy-Littlewood. Hardy grumbled privately to Bertrand Russell that Littlewood supplied ideas while he did all the tedious writing. The Hardy-Weinberg principle arose when the geneticist Reginald Punnett, a cricket companion, posed a problem; Hardy found it very simple and may never have grasped its importance.
He kept to four hours of mathematics a day, leaving the rest for talk and cricket. He held the Savilian Chair at Oxford from 1919 before returning to Cambridge in 1931. His 1940 essay A Mathematician's Apology, which Graham Greene ranked alongside Henry James's notebooks as an account of creative life, was written as his powers faded after a heart attack in 1939. He died in 1947 while his sister read to him from a history of Cambridge cricket.
Source: G. H. Hardy
