*The Man Who Knew Infinity* is the true story (well, “true” in the movie sense of overlapping at least modestly with real people and real events) of Srinivasa Ramanujan.

Ramanujan was a mathematical savant who lived in British colonial India about a century ago. In what schooling he had, he always excelled in mathematics, but he couldn’t sustain an interest in any other subject and flunked out of college.

Even when he wasn’t in school, he continued progressing in mathematics on his own, eventually making what he took to be important mathematical discoveries. He contacted anyone in India or Britain that he thought might be able to help him get some of his results published. Eventually he came to the attention of the great British mathematician G.H. Hardy, who arranged for him to come join him at Cambridge, which he did, and where he proved to be one of the great mathematical minds of his time.

As Wikipedia puts it, “He made extraordinary contributions to mathematical analysis, number theory, infinite series, and continued fractions.” Perhaps he would have made even greater contributions, except he died tragically young, just a few years after arriving at Cambridge.

Then again, I believe mathematics is one of those fields where almost all major advances come from people who are very young. So probably what he did dwarfs what he didn’t live long enough to do.

On the whole, *The Man Who Knew Infinity* is an enjoyable biopic that held my interest well. Now on to a few specifics that come to mind as I think back on the film.

I had the sense that the movie had numerous themes it wanted to cover, but it mostly just introduced them without fully exploring them. So there are one or two or three scenes to make a certain point—e.g., that many British were racist against Indians, that when Ramanujan married and brought his wife into his household this brought about a conflict between the wife and the mother, that Ramanujan’s traveling to England to study was contrary to caste traditions and prejudices, that some Cambridge professors opposed World War I, etc.—but these matters are not then covered more thoroughly once the box is checked.

By the way, in the movie Ramanujan and his newlywed wife look to be a couple of young adults about the same age—about college age, say somewhere from 17 and 25—whereas in real life his wife was 10 when he married her and still only 14 or 15 when he left her behind to journey to England. Evidently child brides as an Indian custom of the time isn’t one of the themes the filmmakers wanted to delve into, so they simply fictionalized that part of his life.

When the movie focuses on the domestic drama in Ramanujan’s life it’s OK, but I thought it was considerably stronger when it focused on his work as a mathematician, including the psychological and sociological aspects of his life at Cambridge and his relationships with Hardy, Hardy’s mathematician sidekick John Littlewood, and others.

I suspect that’s because Ramanujan’s family and in-law conflicts are quite mundane (though not therefore unimportant, especially to the people experiencing them, but the kind of thing you’ve seen in movies—and life—countless times), whereas a native coming from colonial India to London to establish himself as an all-time great mathematician is decidedly not.

The film is quite effective in conveying the gravity, the at times awe-inspiring nature, of the tradition at Cambridge, with its many busts and portraits and such reminding you that you are walking down the same hallways, across the same courtyard, that Newton, Byron, and so many other extraordinary luminaries did centuries ago.

Bertrand Russell, then a Cambridge professor, is only a quite minor character in the movie, but he’s a hoot. I’ve read a great deal by and about him over the years, but I don’t think I’ve ever seen him portrayed in a movie (and the only footage I’ve ever seen of the real Russell was from when he was elderly, several decades after the time of *The Man Who Knew Infinity*). I don’t know how accurate the movie is in this regard, but he’s portrayed as a sort of perpetually bemused commentator on life and the various foibles of humanity.

Russell was one of the Cambridge professors who opposed the war, and in fact was eventually fired from the college and later imprisoned for making public statements against the war, but because the matter of how the war was perceived at Cambridge is peripheral to Ramanujan’s story, the film barely touches on it without going into any of these details.

The film handles the math (or “maths” as they say in England) quite well. Of course without being a high level mathematician oneself one can never fully understand that aspect of Ramanujan’s life, but I felt like as a layman I had at least a decent grasp in broad terms of what Ramanujan and Hardy and the rest of them were working on, which is frankly better than I would have expected.

Ramanujan is depicted as having a real urgency about getting his work published at an early age. He speaks of not wanting his work to die with him. In the movie this feels like a premonition on his part, since he did in fact die young. But in real life, I read later, he had experienced major health problems earlier in his life, so his concern that his work might never be discovered if he didn’t get it out there when he was young had a significant evidentiary foundation.

As interesting as anything in the film are the cultural and individual conflicts (and connections) between Ramanujan and the people he worked with at Cambridge, especially Hardy.

These include his encounters with blatant racism. Many people at Cambridge, including many professors, either assumed that no Indian could do Cambridge-level work, or were indignant that someone non-white would be admitted to their hallowed halls whether they could or not.

Ramanujan was more inclined than Hardy to attribute genius to supernatural causes, which at times put them in conflict. Ramanujan held that his mathematical insights were conveyed to him by a certain Hindu goddess, and at one point informed Hardy that if he didn’t agree with him on this point then it would not be possible for them to be friends.

I’d say that’s quite unfair on Ramanujan’s part. Not because his causal hypothesis about the source of his mathematical abilities is implausible (though it is—whatever tiny chance there is that such things come about due to supernatural causes, the likelihood that the specific supernatural cause would be this particular obscure deity of one particular religion would be some minute fraction of that tiny chance), but because it isn’t a necessary part of friendship to agree with all of a friend’s beliefs, even those that have the most emotional importance for the friend.

I mean, imagine the roles reversed. I’d also disagree with Hardy if Hardy insisted that in order for them to be friends Ramanujan would have to agree that mathematical genius is fully explicable in terms of neurons firing in brains and other wholly material factors (or whatever it is Hardy believed), even though on the merits that causal hypothesis is much more likely than Ramanujan’s.

Their most significant conflict about the work itself is that Ramanujan tends to jump ahead to the conclusions using his extraordinary mathematical intuition, while Hardy and the other Cambridge professors keep trying to impress upon him that in mathematics (and in science for that matter), if you can’t prove it, it doesn’t count.

Ramanujan has little patience for this, based in part on his concern that he has only a very limited amount of time left to complete as much important work as possible. Once he has intuited some important mathematical principle, to then go back and painstakingly construct a step-by-step proof that leads to that result means using up time that could better be spent coming up with the next big discovery.

I think most movies would have favored Ramanujan’s position here, as most layman would probably find it more appealing to root for the rebel genius protagonist of the film in his efforts to not be held back by the lesser minds trying to bind him by their rules that are more fitting for mediocrities and conformists. But to its credit, *The Man Who Knew Infinity* doesn’t do that.

Because surely Hardy, et al, are right. “This formula’s correct; just trust me” is no way to do mathematics. It might be tedious to someone like Ramanujan to have to construct a proof for something whose truth he is convinced he has already “seen,” but it’s necessary.

The movie, I think, handles this well in that it portrays Ramanujan as a great mind, but also makes it clear that his intuitions were not infallible.

Typical is an occasion when he comes up with some significant result in the area of prime numbers, mostly based on intuition (or his secret messages from that goddess). Littlewood then does the grunt work of checking it out in detail. The conclusion he reaches is that Ramanujan’s claim is in fact false, but that it’s so much closer to correct than he would have ever expected that it puts him in awe of Ramanujan’s mathematical brilliance.

The message, and it’s one that I find agreeable, is: Yes, Ramanujan is a genius, and his mathematical insights are extraordinary, but not to the extent that he is justified in playing by different rules. It’s still necessary to verify his work with proper proofs, just as any other mathematician would need to.

*The Man Who Knew Infinity* didn’t impress me at some very high level, but it’s a competent, entertaining, thoughtful film that earns a moderate thumbs up.