Turns out that if you're alone in the wilderness and your arm is wedged under a rock, cutting it off with a dull knife isn't as easy as you'd think.
No, indeed. As we see in "127 Hours," you must first break the bone in your forearm, because there's no way the pocketknife is going to . . . hack it.
Only then can you begin stabbing away at the putrid flesh of your blood-starved arm (grow up, it was dead anyway). Then you drink your own urine for strength (you've been thoughtfully saving it), rappel down a cliff and walk out of the wilderness, into the future you've made for yourself.
And you walk out a better person, because during your 127 hours alone, confronted with your shortcomings, gripped by a starvation-induced vision of a family you might one day have, you realize what a selfish person you are.
Drink. Hallucinate. Change.
As a travelogue and spiritual journey, which it is, the fact-based "127 Hours" is the self-effacing antidote to "Eat Pray Love" (as the movie "Saw" might have been had it been made by moral beings).
It also asks us to take a second look at a character our culture has celebrated since "Walden," the nature-worshipping recluse who turns his back on civilization with an indignant huff.
And who better to defend the virtues of civilization than Danny Boyle, cinema's last great believer in humanity.
He begins with a terrific sequence - gung-ho adventure-junkie Aron Ralston (James Franco) packs his gear, loads his truck and tears off down the highway as the city, its crowds and its sprawl recede, and Ralston arrives in the purifying wild.
There, he indulges in the pleasures of total withdrawal and retreat. Well, almost total. He meets a couple of girls, they bathe in a secret Eden of cool canyon water, and again he vanishes, with his monklike determination to be by himself.
Then, abruptly, Ralston hits the downside of being utterly alone. He falls into a crevice, a rock falls on his arm, and the movie of landscapes and movement suddenly stops to contemplate Ralston's immobilized ordeal.
The first shot is a brilliant one.
Up through the crevice we see a blue strip of sky, crossed by the glinty silver trail of a passenger airplane - neatly summarizing the movie's contrasts and themes, illustrating the gaping chasm between the busy world and the solitary Ralston, now in a life-or-death struggle to rejoin it.
Staging this one-man show of wilderness survival obviously made director Boyle a bit nervous, and visually he's the nervous type already. The "Slumdog Millionaire" director reaches deep into his bag of tricks to make the ordeal cinematic - it's busier than it needs to be.
And reputedly horrific, when it gets down to arm-severing time. People, they say, are fainting. If that's true, I'd say these people lead insulated lives. Am I the only one who went to a high school where cops showed up at driver's ed with footage of teenagers mutilated in auto accidents? This is nothing compared with those.
More brutal is Ralston's self-appraisal, delivered via flashbacks and monologues that show him reflecting on his life. He realizes, for the first time, how self-indulgent his solo retreats have become. Ralston confesses as much in a video he makes for his parents, and I'd be shocked if these scenes do not earn Franco an Oscar nod.
Ralston thinks he's going to die, and he realizes the cause of death isn't the rock. It's his self-imposed exile. He didn't leave a note, and had no one to leave a note to.
We know via Ralston's infamous ordeal (and his book) that he does not die. He does walk out, and Boyle gives us the clever money shot - he reverses his opening montage, and also its meaning.
Faceless, teeming humanity and its madding crowds return, and Ralston, back from the void, is glad of it.