I once ran a 10K for charity while living in Amman, Jordan. I’ll always remember the surreal, final stretch of the race: the sidewalk was crowded with people watching, but no one was cheering or clapping. Mostly, the locals just looked confused. Running for running’s sake, it seemed, didn’t register strongly there. And while Jordanians obviously value charity, running for charity didn’t seem to make much sense to them either. When I thought about it, I had to admit, raising money by doing a race is kind of a non sequitur: People should donate money to some cause because I’m going to push myself physically for a few miles? In these events, do we run so we can selflessly raise money, or do we raise money as an excuse to run for our own sake?

That’s the question that kept bothering me while watching Elevation Change, a new documentary that will start streaming on Amazon, iTunes, and Vimeo today. The film follows 24-year-old ultrarunner Sam Fox, who ambitiously—but ultimately unsuccessfully—attempts to break the Pacific Crest Trail speed record in 2011. At the same, he raises money for the Michael J. Fox Foundation in honor of his mom, who has Parkinson’s disease. It has all the makings of a boring film about physical accomplishment for a good cause, but first-time filmmaker Marion Mauran instead takes an unusually honest and thought-provoking look at the story’s protagonist and his motives.

The film begins by introducing Fox, a Thor-haired, former Yale high jumper who thinks he can hike the Pacific Crest Trail faster than anyone ever has before—and raise a quarter of a million dollars for charity while he’s at it. But Fox’s over-the-top confidence starts to break down when injuries and exhaustion stop him from meeting the daily mileage he needs to break the record. Visibly frustrated, Fox appears to rationalize his failure by claiming that setting a record was always a secondary objective. The true purpose of his thru-hike was always to raise money, Fox insists, somewhat unconvincingly. In the end, he hikes 2,257 of the trail’s 2,650 miles in 62 days, which is slower than the record pace, and does not reach the Sierra Nevada before winter sets in, forcing him to skip a section of the trail. But he does surpass his fundraising goal, earning $300,000 dollars.

Throughout the film, Mauran puts Fox’s irritable arrogance front and center. His less than charitable attitude and early obsession with setting a speed record force you to question the depth of his altruism. Did this guy hike the trail because of his mom or because he wants to be the best? It feels like Fox is indulging in motivational double-dipping in order to claim the title of both hero and conqueror. “There is a level of overconfidence and cockiness that comes with any kind of success,” Fox tells the camera before his hike. “I’ve been accused of being cocky my entire life, being overconfident, being a dick. That’s fine, I have no problem with it. I’ve accepted that.”

Elevation Change handles the messy line between Fox’s large ego and his altruism with a deft touch. The film makes no attempt at handing its viewers a satisfying answer to his ambiguous motivations. You have to sort through the moral complexities yourself. It’s actually the best part about the documentary, and I’m not sure the film could have worked any other way.

Speaking with me over the phone eight years after his attempt, Fox was much more thoughtful and humble than he seems in the footage of him during his quest. He told me that, in hindsight, his motivation was probably partly charity and partly personal achievement, swinging from one to the other depending on his mood. “Let’s call it 50/50,” says Fox. But it was the naked ambition of his goal, he says, that allowed him to bring attention to his fundraiser and successfully generate a significant amount of money for charity. Otherwise, nobody would have cared.

So maybe it’s misguided to care what his, or anybody else’s, motivations are. If people keep wanting to run for charity and others keep donating because of it, why question if it’s a good thing? I’ve raised squat for Parkinson’s disease. In 2015, Fox biked to and climbed the highest peak in each of the lower 48 states, helping raise $2.5 million more for the Michael J. Fox Foundation. Runners around the world have, in the recent past, raised more than a billion dollars a year for good causes. Maybe I should stop thinking so much and start running for charity a little more.