Saturday, April 9, 2016

Book Review: The Man Who Knew Infinity

The Man Who Knew Infinity: A Life of the Genius Ramanujan
Robert Kanigel
Biography, Mathematics

There's always a debate about genius. Are there people who just have an inexplicable gift for something? Or is it simply a matter of getting ten thousand hours of practice?

To some extent this is a false dichotomy. To put in 10,000 hours on anything, particularly if you do it as a youth, you've got to be abnormally attracted to that thing. All the same, my personal intuition leans toward the inexplicable-gift side. I thought about that a lot while reading The Man Who Knew Infinity.

I'm not bad at mathematics. I use basic probability and statistics all the time. I have a degree in a science (astronomy) that uses math pretty heavily. I sometimes even do math-oriented puzzles for fun. But numbers don't "speak to me". I don't love mathematics.

Ramanujan--born poor in India in 1887, with little or no formal training, ignored for years by the mathematical establishment--did love mathematics. "Love" may not be a strong enough word. He was a smart young man, who did well in all his classes ... until he got hold of a mathematics book. After that, he wouldn't--maybe couldn't--study anything else. His gift eventually made him famous; by bringing him to England, it may also have killed him.

It's easy to mythologize someone with such an outsized talent and moving life story. The Man Who Knew Infinity does a terrific job of humanizing Ramanujan. It's less successful at conveying the details of his mathematics, but I'm not sure how you could do better. Kanigel chose to assume that his readers don't have even a high-school level of numeracy, which irritated me, but to make any other assumption would probably have irritated a lot of other people. It would have been nice to get the actual details even one of Ramanujan's extraordinary proofs--as things stand, we have to take it on faith that they really were as strange, as beautiful, and as unexpected as other mathematicians say they are--but I don't know that that would be possible.

So the book is, perhaps, as successful as it could be. By focusing on Ramanujan as a person--his religious devotion, his friendship with the English mathematician G. H. Hardy, his sternly vegetarian principles, his homesickness--it makes him accessible. Or maybe it only makes him seem accessible. Ramanujan's torrid love affair with numbers is not something that can be conveyed in text, nor experienced by most mortals.

The Man Who Knew Infinity has a fair amount in common with Andrew Hodges's insightful Alan Turing: The Enigma. The latter was the loose basis for the excellent (though quite inaccurate) film The Imitation Game; and, as it happens, a film based on The Man Who Knew Infinity will be released soon.


  1. I think some people do have gifts. It may be genetics or brain structure. Or maybe it's vitamins, I don't know. But there are enough stories (admittedly just stories - so how would I really know) that show that certain people really are just different - or better - at some things.

    I heard of a guy who hit his head when diving into a pool and came out with some brain damage, but also able to play the piano. Or a woman who literally had no fear, probably because part of her brain is calcified. Or children with hyperlexia and can read as toddlers.

    So maybe different brains really are different, and that's where the genius comes from.

    1. It's hard to separate anecdote from reality in this area, but I tend to agree with you. There do seem to be some documented cases where brain damage actually unlocks some ability--it's sometimes called "acquired savant syndrome". The author and neuroscientist Oliver Sacks has written of a couple of examples, if I remember correctly.

      The specific case I was thinking of was Mozart. He played keyboard and violin at age five, and wrote his first symphony at eight. Some people--Malcolm Gladwell is one--say, well, his father Leopold was an ambitious musician and pushed little Wolfgang to his limits, and that's how he got ten thousand hours of practice, which made him a genius. But, aside from anything else, getting a normal eight year old to put in TEN THOUSAND HOURs on anything sounds just impossible. The only reason I can imagine any kid doing that is if they had an unnatural, obsessional interest in the subject. I.e., a gift.

  2. According to Wikipedia, his notebooks were memorialized in print. And guessing by this article found in a footnote, either Trinity or the College of Liberal Arts & Sciences (U. Illinois Urbana-Champaign) has them?