The Story of Paul Erdõs and the Search for Mathematical Truth
Paul Erdõs was preparing for eye surgery when he asked the surgeon if he would be able to read. The surgeon replied that – of course – that was the entire purpose of the procedure. So minutes before the surgery was due to start, a group of mathematicians were summoned from the nearest university to come and help him work on a paper while under the knife. If he was unable to do mathematics during the surgery, he wouldn’t have the surgery at all.
It is unsurprising that a man this dedicated wrote more papers than anyone else in the history of mathematics, with more than 1500 publications to his name. Described by Time magazine as the ‘Oddball’s Oddball’, Erdõs was an eccentric genius, obsessed by mathematics and often detached from reality; something that Paul Hoffman never shies away from admitting in The Man Who Loved Only Numbers. However, this portrait of the man is sympathetic; attempting to justify his unusual life choices and recounting anecdotes with affection.
The Man Who Loved Only Numbers was based on Hoffman’s 10 years of interviews and travels with Erdõs. It is an unconventional biography, being made up largely of a series of vignettes which, over 300 pages, build up a colourful picture of Paul Erdõs and his mathematical world.
Erdõs (a Jewish-Hungarian) was a fine mathematician, responsible for the elementary proof of the prime number theorem as well as development of combinatorics, Ramsey theory, graph theory and numerous other areas. However, he is best known today for his lifestyle; Erdõs was the travelling monk of mathematics. He lived a life of celibacy, gave away most of his money and had no permanent home; instead travelling from continent to continent, staying in other people’s houses. He lived by the philosophy of ‘Another roof, another proof’, working obsessively on a new paper in each house and recruiting whoever was nearby to collaborate with him; academics and children alike. He was inexhaustible, doing 19 hours of mathematics every day, fuelled by coffee, amphetamines and curiosity. Once a project was complete, he would move on, usually spending no longer than two weeks under each roof.
Despite his incredible mind, Erdõs struggled with simple everyday tasks. Hoffman’s book is, at times, hilarious (readers will find it difficult not to giggle at the story of Erdõs trying to slice a grapefruit with the wrong part of a knife). However, our laughter does not detract from our admiration. What makes these anecdotes in The Man Who Loved Only Numbers so funny is that the daft behaviour came from one of the greatest minds of the past century.
It could be argued that this biography does Erdõs a disservice by referring to him as loving ‘only numbers’. Mathematics may have been his raison d’être, but he was far from inhuman. Erdõs was full of charity, energy and humour (his peers described him as a ‘vaudeville performer’). He was also sociable, affectionate towards children, loyal to his friends and an extraordinarily collaborative mathematician, working with anybody, including those without formal mathematical backgrounds. During his life he wrote papers with more than 500 people, which has resulted in the concept of the ‘Erdõs number’ (describing how closely linked any academic is to Erdõs).
Readers are given an insight into Erdõs’ relationship with mathematics through a description of his own peculiar language. To be married was to be ‘captured’, to stop doing mathematics was to ‘die’ and God was the ‘supreme fascist’ or ‘S.F.’. Erdõs would describe the S.F. as holding ‘The Book’, which contained the universe’s mathematical secrets. This study of Erdõs’ language reveals why he was entirely dedicated to mathematics; to discover the mathematical secrets in The Book gave him deep fulfilment. Erdõs’ passionate, pure and complete dedication to mathematics could make some readers regret having left academia.
The Man Who Loved Only Numbers often deviates from Erdõs’ story to describe the lives and achievements of other pure mathematicians, such as G.H Hardy, Srinivasa Ramanujan and Erdõs’ lifelong friend, Ronald Graham (of Graham’s number), using Erdõs as an intersection between them. This provides a useful background to the portrait of Erdõs and captures a sense of the excitement of 20th Century mathematics. While Hoffman touches on various areas of pure mathematics (largely number theory), it is notable that for a book about a mathematician, The Man Who Loved Only Numbers contains little mathematical detail. This could be frustrating for those hoping to learn about Erdõs’ work. The inclusion of some of Erdõs’ major proofs as appendices make this book more appealing to those with strong mathematical backgrounds.
Despite being low on technical detail, The Man Who Loved Only Numbers is an accessible, moving and often humorous ride providing a very human look at a mathematician often described as inhuman.