The Man Who Knew Infinity: a book review


The Man Who Knew Infinity by Robert Kanigel (1991)

I recently, and somewhat belatedly, read Robert Kanigel’s The Man Who Knew Infinity, a biography of the brilliant Indian mathematician Srinivasa Ramanujan. A partly fictionalised film based on the book was released in 2015 (see Scott Aaronson’s review of the film here).


Whewell’s Court, Trinity College, Cambridge, where Ramanujan lived when he first arrived in England in 1914 (photo: Cmglee)

Ramanujan had one of the greatest mathematical intuitions of all time (he himself credited his insights to the goddess Namagiri). However, his brilliant guesses were as likely to be wrong as right. Furthermore, Ramanujan often neglected formal mathematical proofs, so that the work of separating the many diamonds from the occasional paste was frequently left to collaborators (like G. H. Hardy, who invited Ramanujan to England, and who wrote several joint papers with him). There are still results in Ramanujan’s journals which have neither been proved nor disproved (see this perspective on Ramanujan by Stephen Wolfram).


One of Ramanujan’s formulae for π

Interest in Ramanujan seems to have peaked at around the year 2000, according to Google Ngrams (although this does not include the influence of the recent film):


Google Ngrams search for Ramanujan’s name in books

I found Kanigel’s book a very enjoyable read. There is extensive biographical detail, albeit with a few misquotes, and with apparent confusion at times about the language of a century ago (e.g. the word “cult,” used in a technical sense to mean “a particular system of religious belief,” referring to the Brahmin version of Hinduism which Ramanujan followed). Kanigel does not quite succeed in fitting Ramanujan into a larger context – I would have liked a bit more discussion of Ramanujan by other mathematicians. And I cannot help but wonder what would have happened had illness (probably chronic hepatic amoebiasis, although Kanigel suggests tuberculosis) not killed Ramanujan at the tragically young age of 32. I guess nobody can imagine what further mathematics we might have seen.

See here and here for other reviews of the book.


The Man Who Knew Infinity by Robert Kanigel: 3.5 stars


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