You will have to take my word for it that I hadn’t read any review of In The Light of What We Know by Zia Haider Rahman before I read the book. I bought it off the Net simply because the author seemed interesting: born in rural Bangladesh, educated at Oxford, Cambridge, Munich and Yale, former Wall Street investment banker and human rights lawyer. The book seemed certainly thick enough at 550 pages to carry me through a few tedious days of planned hospitalization.

What I discovered was a stunning piece of literature that had just dropped into my lap, unheralded and unexpected. In The Light is, quite simply, an astonishing feat. It is certainly the finest novel I have read this year and for many years. In its ambition, scope, scholarship, philosophical depth, sensitivity, quality of writing and stylistic manoeuvres, it far outstrips anything written in English by any subcontinent-origin author, at least anything I have read.

It’s a prodigiously hungry novel. It wants to encompass all of human existence and beyond—the very concept of reality. The unnamed narrator puts it woefully simplistically when he says that the story of Zafar, his friend (and the novel’s protagonist) is “the story of the breaking of nations, war in the twenty-first century, marriage into the English aristocracy, and the mathematics of love". Yes, all that is there: the Bangladesh Liberation War, the near-surreal confusion in post-Taliban Kabul, deadly ISI intrigues, the strange self-imposed constraints that the British upper class work under, heartbreak and more. Yet, to define this book in such narrow terms is like saying that Ulysses is about a day in the life of an advertising canvasser called Leopold Bloom, or Gravity’s Rainbow is about the German V2 rocket.

But we figure out as we go along that the man telling us Zafar’s tale is not the most perceptive of human beings, and is a deeply flawed character, not above betraying his closest friend in his greatest hour of need.

One morning in September 2008, the narrator finds his long-lost friend standing at the doorstep of his South Kensington home. The two men, now in their late 30s, had studied mathematics together in Oxford, and had been colleagues in a Wall Street investment bank.

Though both are South Asian, they could not be more different in their backgrounds. The narrator is the scion of an extremely wealthy and influential Pakistani family, and his father is a physics don at Oxford (his grandfather bought him his house in plush Kensington even before he got his first job). Zafar grew up in a dirt-poor little-educated Bangladeshi immigrant family in London and has made his way up in the world through sheer merit. Indeed, he learns early in his boyhood that his real father is an unknown Pakistani soldier who raped his mother, the sister of the man he knows as his father, during the 1971 Bangladesh War.

Both are at a crucial point in their lives. Post-Wall Street meltdown, the narrator is about to lose his job for trading in “mortgage-based securities, collateralized debt obligations, credit derivatives, and everything else that was now being laid for a bonfire, while my own firm was tying me to the stake, to satisfy a public’s lust for blood" (Among other things, In The Light provides the most succinct and lucid explanation of what caused the securities market crash that I have read). His marriage is also quietly—not so much collapsing, but decaying away. And Zafar, who hasn’t met his friend since having a nervous breakdown eight years ago, needs to tell the story of his life, he needs to confess. Only by laying himself bare to someone can he hope to achieve some peace, both emotional and intellectual.

Though it moves between London, Oxford, New York, Princeton, Islamabad and Kabul, with a brief interlude in Bangladesh, In The Light is essentially a lengthy rumination on perception, knowledge and truth. Almost the entire story is told through a conversation between the two friends that carries on over the course of five months, and like most such conversations, is hardly linear.

There are major digressions into seemingly tangential topics, tales are dropped halfway and picked up several chapters later, Zafar’s spoken reminiscences are mixed up with the narrator’s own private memories, and the structure of the narrative resembles an elaborate and convoluted route plan pencilled over a complex topology.

The narrator recalls his father mentioning that the properties of sub-atomic particles become known only when the particles rub against each other. The interaction between the two men helps them know themselves, and in the narrator’s case, is perhaps a path to redemption and growth.

The fundamental question this novel asks is: Can we ever know the truth about anything? Rahman takes on the big issues of life—love, betrayal, race, class, greed, faith, belonging and exilehood—drawing on discoveries and perspectives from a dazzling array of disciplines and connecting them subtly with insight and imagination—evolutionary biology to literature, sociology to quantum physics, psychology to cartography, and above all—or rather, underlying lying it all—mathematics.

“Mathematics is unique in all human endeavour," says Zafar (in this case, echoing his creator, who has said in interviews that he believes that mathematics is the most creative of all arts). “Nothing that is proven in mathematics…can be assailed or undermined…Mathematics,…pure mathematics, the product of the human mind turning to face itself, turning into itself, and finding in the realm of necessary consequences, where no contingent fact is to be seen or heard or smelled or tasted or touched—it discloses a beauty that exhausts human comprehension and a certainty the senses can never touch. No other effort in this world can deliver a thing of such exhilarating beauty that is also true in that way, IN THAT WAY, I say, whose beginning and end are one and the same, which requires no venture beyond the cranial cage, no reliance on the perceptions that deceive or the memory that corrupts, no appeal to anything experienced."

But if mathematics provides a truth that is immutable, and independent of even the existence of any life in the universe, the true nature of all human inquiry has always been to represent or translate reality in order to understand it. “Consequently, the loss of information and understanding that every act of representation involves is the effect of an act of destruction that serves a need…Every time we want to understand anything, we have to simplify and reduce and, importantly, give up the prospect of understanding at all, in order to clear the way to understanding something at all."

In essence, says Rahman, we reduce reality to a metaphor we are comfortable with, because metaphors “take us back to a familiar vantage, which is to say that a metaphor cannot bring anything nearer. Everything new is on the rim of our view, in the darkness, below the horizon, so that nothing new is visible but in the light of what we know."

Yet mathematics ends with Godel’s Incompleteness Theorem, stated and proved by the Austrian mathematician Kurt Godel. Zafar is obsessed with the theorem (like several other very bright people I have known in my life personally), and the entire superstructure of In The Light rests on this mathematical truth.

In its simplest form, what the theorem says is that within a given system, there are claims which are true but which cannot be proven to be true. The implications are shocking and of infinite range.

In specific terms, it proves that mathematics cannot be proven to be consistent—consistency being the simple assumption that, given a set of axioms, using logical reasoning, it is not possible to derive two different statements which contradict each other. In philosophical terms, the theorem implies two equally valid possibilities—that there are no absolute truths, and there is an infinite number of truths, but which we can never know for certain to be true. Does God exist? Yes, and I can use Godel to say so without fear of being proved wrong. No, and I can use Godel to say so with total certitude.

In The Light ends with the realization that Zafar—as well as the narrator—comes to: that “understanding is not what this life has given us, that answers can only beget questions, that honesty commands a declaration not of faith but of ignorance, and that the only mission available to us, one laid to our change, if any hand was in it, is to let unfold the questions, to take to the river knowing not if it runs to the sea, and accept our place as servants in life." This is, without doubt, a religious statement.

Zafar’s restless quest is driven by his deep sense of exile, of rootlessness. In The Light begins with a quotation from Edward Said: “Exile is the unhealable rift forced between a human being and a native place, between the self and its true home: its essential sadness can never be surmounted." Zafar is the product of a violent assault by one culture (West Pakistan) upon another (East Pakistan). He is born in the district of Sylhet, which was the only province in then-Eastern India where a referendum was held to decide whether it should go to Pakistan or merged with Assam. Though the result went in favour of Pakistan, the area of Sylhet where Zafar comes from (“that corner of the corner of the world") voted to be merged with Assam but was anyway given to Pakistan (Coincidentally, my family comes from that same area, and I have never been there. I cannot deny that a little bit of the thrill I got from reading In The Light derived from that fact.).

He is brought up by two people who are not his biological parents, in an alien land whose very language his “parents" cannot muster beyond a point. He goes to an university—Oxford—crammed with the elite, and falls in love with Emily, from an impeccably upper-crust British family, who is the evolutionary end-product of centuries of behavioural conditioning: “doors opening and closing; the liminal presence of unspoken affairs; the air of good manners in which honest interest about the truth of people seemed vulgar; and above all the exquisite handling of information, the withholding and release, like an inch on the reins of a dressage horse; all these things were of essence to the conduct of their lives."

He is sent off to Afghanistan on a mission never fully explained to him, but something to do with the reconstruction work in that country. But every person he meets seems to have his or her own hidden agenda, including a mysterious and powerful Pakistani spymaster whose allegiances are multi-layered and chameleonic. “Some people think that chess is about the pieces," he tells Zafar. “But in fact, it’s about the board. And you learn only from playing game after game."

Zafar is never and nowhere at home. He finds himself situated constantly in the gulf between races, cultures, classes, the East and the West (“The West always sees the East through itself"), between the sciences and the humanities: “Bridges are fragile things. A bridge belongs to nothing, to nowhere. The mind settles on the emptiness between its ends, a region of suspended animation." As a child, on his first visit to Bangladesh, he walks across a railway bridge in rural Sylhet, only to see it collapse immediately afterwards, taking the train which he had been on till minutes ago, down into a swirling river.

Zafar’s life, to a significant extent, reflects Rahman’s own. Like Zafar’s, Rahman’s parents migrated to Britain when he was a child. Like Zafar’s father, Rahman’s worked as a bus conductor and a waiter in London. Both got a seat at Oxford to study mathematics, and both studied law afterwards (Rahman at Yale, Zafar at Harvard). Both worked as investment bankers and human rights lawyers. Rahman has admitted that he has suffered from the same inability to communicate with his parents as Zafar did. Zafar has the same enthusiasm for carpentry that Rahman has. In The Light, thus, is intensely autobiographical, a work of almost heroic honesty.

That honesty is enriched by the gift of mathematically precise and precisely mathematical analysis. Rahman’s is surely the most intelligent and philosophical voice to come out from subcontinental roots since Salman Rushdie (who is an extremely different writer, so there is no basis at all to compare the two, except on the parameter of numinous talent).

Yet, this breathtaking debut novel is not really about Bangladesh or Pakistan or Afghanistan or South Asia. Its themes are absolutely universal, and the several story lines are metaphors—yes, the metaphors that keep us from understanding the true nature of reality—for the biggest questions that have haunted the human mind for ever. Zafar’s journey an allegory of an eternal quest. That quest will never end, and the two friends who talk their through the book—one scarred repeatedly and nearly broken by life, and the other less of a man because he has never been scarred—come to realize the one unimpeachable truth that we have been allowed in this world. That the quest will be never-ending.

But, as Godel proved beyond doubt, even that truth cannot be proven. We progress only in the light of what we know. Or think we know.