A teenage boy at one end of a lifeboat, a Bengal tiger at the other, and nothing but Pacific in every direction. That is the picture on the poster and the reason most people buy a ticket for Ang Lee‘s Life of Pi. A premise this good could have rushed to the water. Lee holds it back behind a long first act instead. By the end the film has asked what it means to believe a story, and it answers with a gamble that few adaptations of a beloved novel would risk.

The source is Yann Martel’s novel, published in 2001, which won the Man Booker Prize the following year and has sold more than ten million copies, even though at least five London publishers turned it down first. David Magee wrote the screenplay. Piscine Molitor Patel grows up in Pondicherry, the son of a man who runs a zoo, in the French enclave that India did not receive until 1954, as The Guardian reminds us. The structure nests one narrator inside another. An unnamed Canadian writer, played by Rafe Spall and whom The Guardian takes to be Martel himself, is told that a man in Montreal has a tale that will make him believe in God. That man is the adult Pi, Irrfan Khan, a philosophy teacher who starts from the beginning.

The beginning is a joke about names. Pi was christened after the Piscine Molitor, a Paris swimming pool an uncle adored, and after schoolmates made jokes about pissing he reinvented himself as the Greek letter. Three actors carry him from childhood to the lifeboat: Gautam Belur at five, Ayush Tandon at twelve and Suraj Sharma at sixteen. In the novel the tiger gets a comic name of his own, Richard Parker, the product of a clerical error that swapped the animal’s name with that of the man who captured him. The film is at its best when it plays with these small absurdities. They tell you early that its solemnity comes with a sense of humour, and that the director will not ask you to take every grand idea on trust.

Then there is the look of it. The Guardian praises the film’s sense of the mysterious and the magical, from the opening shots of animals strutting and preening in a sunlit zoo to the closing credits of fish and nautical objects shimmering under the sea, and credits the hallucinatory 3D for compounding the effect. Film Comment, a far more guarded voice, describes the opening as a pop-up-book display of giraffes, monkeys, pink flamingos and a sloth dangling from a tree. It still concedes that this is the most visually splendid film of Lee’s career. I side with the admirers. The zoo sequence is unabashedly pretty, but it also plants the idea that every creature in this story will be looked at twice, once as an animal and once as a symbol. The Movie Elite reviewer distrusts Lee’s artier tendencies and cites The Ice Storm as one of the most boring films he has seen. Even so, he calls the sinking of the ship incredible and says he could not tell the tiger from a real one, despite looking for any sign of fakery. That is the right test for a film that depends on a digital cat to carry half its scenes.

Pi’s spiritual education gives the first act its purpose. He is raised a Hindu and a vegetarian, and at fourteen he investigates Christianity and Islam and decides to belong to all three faiths, to the dismay of his parents and his religious mentors, because he just wants to love God. His father, Santosh Patel, played by Adil Hussain, is the rationalist who wants none of it. The Guardian notes that the film treats this spiritual journey with a respectful wit as the boy rejects his father’s rationalism, and that tone is the picture’s best quality. It does not mock the boy’s faith, and it does not let that faith harden into a sermon. Tabu plays his mother Gita, and the brother Ravi is played at three ages by Ayaan Khan, Mohd Abbas Khaleeli and Vibish Sivakumar. Together they sketch a family in a few strokes, and the sketch is enough to make the later loss register.

The cost of all this patience is pacing. The Movie Elite reviewer says that for the first forty minutes his doubts were all but confirmed: it was amusing and well acted but did not go anywhere for him. He wonders why the film spends so long introducing a character before stranding him. The complaint is fair, and a viewer in a hurry will feel it. My answer is that the setup is not wasted. When the ship goes down and Pi is left with a hyena, a zebra, an orangutan and the tiger, the faith established in the first act is the only thing he has left to hold on to. The same reviewer admits that once Pi is stranded the film picks up and keeps moving, and that the scenes between Pi and Richard Parker, with nothing around them but water, were worth the slow burn.

The lifeboat is where Lee earns his reputation. Simbasible singles out the relationship between Pi and the tiger, calling it fascinating, and praises the film for showing animals as animalistic and never too humanized. I agree, and it is the decision that keeps the middle stretch tense. Richard Parker is not a pet or a cartoon sidekick, and the boy’s survival depends on respecting that. The same reviewer is less convinced by the lead. He finds Sharma good but not mind-blowing, and says he expected more depth from the character. I think that criticism is partly right. The script gives Pi a great deal to endure and comparatively little to say aloud about it. Khan, in the framing scenes, supplies some of the reflection that the boy cannot yet voice, and that division of labour is the film’s way of covering the gap.

Then comes the turn the whole structure has been preparing. The film offers two versions of the story, one with animals and one without, and asks the audience which it prefers. Simbasible found that double ending deep, thought-provoking and emotionally rewarding. The same review admits the film risks becoming too schmaltzy at times before Lee finds the balance between heart and realism. Film Comment is harder on him. It accuses Lee of blatant Oscar-hunger and of a perpetual tactfulness toward quality source material, and it says the film is so innocuous that it is hard to see why it leaves a bad taste. I see the point about tact. A film this eager to please keeps its sharpest edges out of reach, and the second version of the story never quite hurts as much as it might. But the finale still works, because it makes the audience complicit in the choice. We want the tiger, and the film knows it.

The numbers back up the critics who liked it. Roger Ebert called it a miraculous achievement of storytelling and a landmark of visual mastery. Rotten Tomatoes lists it at 86% on the Tomatometer, with a running time of two hours and five minutes. Simbasible reports more than 600 million at the box office and eleven Academy Award nominations, a haul that brought Lee his second directing Oscar, after Brokeback Mountain. Few directors could pivot from a gay western in Wyoming to a castaway fable in the Pacific without losing their footing. The Guardian traces Lee’s career from Jane Austen‘s England to Nixon’s America, and from medieval China to wartime Shanghai, with the style changing every time the subject does. Life of Pi extends that run rather than repeating any of it.

The first act drags, the hero is less layered than his ordeal, and the tact can read as caution. What the film gets right is harder to find. It commits to a difficult idea, that the story we choose to tell about suffering is itself an act of faith. It stages that idea with a boy, a tiger and an ocean, and it never lets the spectacle drown the argument. The Guardian likens the tone to Robinson Crusoe rewritten by Laurence Sterne, which is generous but close. The question of which version of the truth you would rather live in is still open when the credits finish, and the film is content to leave it that way.