SO MAYBE “SAVING THE WORLD” starts with a black screen. Or a phone call. Or a question. The story goes like this: In 2004, a girl in New Orleans needs help. Nadia, currently in fifth grade, has done poorly on her math placement test, and been placed on the remedial track. Her incomplete understanding of math, with “swiss-cheese-like” holes, familiar to any of us who have been ushered hurriedly through public education, has now caught up to her. Frustrated, she decides to dial her older cousin. He holds two degrees from MIT and a hedge fund job to his name—surely he’ll be able to help.

His name is Salman Khan. 1,525 miles away on the east coast, he is newly married and scrambling to jumpstart his finance career. Still, he finds time after work to patiently work through problems with Nadia, using Yahoo! Doodle and phone calls.

This is how it begins. As Nadia improves in math class, her family notices. Over time, Khan picks up her brothers Arman and then Ali as clients, then other cousins and family members. In 2006, to ease the burden of scheduling with his many family members, he takes to Youtube. From there the growth is easy and obvious—Youtube hasn’t seen an online tutor like this before. After work, he hunches in his closet at home, his “toddler’s red Elmo underfoot,” scribbling on a tablet and recording videos into a headset. In a few years, his channel, Khan Academy, gains over 458 million views. Three years later, in 2009, he quits his job to pursue his channel full time.

Eleven years after he first hit Youtube, it is my turn to be on the phone with him, and he sounds nothing like he does in his videos, videos that have since grown to service over 62 million users in dozens of languages, that are now a standard pillar of the American high school experience, that I have fallen asleep to and risen to and eaten lunch to, as he’s counseled me through grueling physics classes, every type of calculus, and American history. Online, he’s like a friendly butler: paternal, polished. Over the phone, although it’s early in the morning, he’s warmer and more effusive. His voice rises and falls freely, like I’m a friend at a bar, or he’s delivering a funny anecdote. He keeps breaking into these hearty chuckles.

The way he tells it, “saving the world” started with a book. “I read a lot of science fiction,” he explains. “Have you read The Foundation Series by Isaac Asimov?” I say I haven’t. “Actually, it was my Christmas gift for a lot of folks this year. It happens around ten or thirty thousand years into the future. The Galactic Empire is about to enter the dark ages. This guy, Hari Seldon, starts the Foundation in order to shorten the coming dark ages. It takes all of humanity’s knowledge. I was like, what if Khan Academy could be like The Foundation? What if?”

Since then, some version of Khan’s dream has come true. If not spanning all of humanity’s knowledge, his organization certainly makes a dent in it. Covering basic addition to string theory to financial literacy, it seems possible to eke an entire education from his service, and people have. One high-profile case Khan likes to mention in his talks is Sultana, the Afghan refugee. Banned from learning by the Taliban, she’d wake up at 5 A.M. to illicitly watch Khan Academy videos. She used that knowledge to pass an SAT she smuggled herself out of the country to take, and ultimately earned a spot at Arizona State University. Today she researches under one of the most prominent string theorists in the U.S. Another example is Zaya, an impoverished Mongolian orphan who taught herself enough to become a contributor to Khan Academy herself. There are thousands more testimonials online, a few of which Khan himself can proudly recite from memory.

Khan Academy’s most salient feature is its total lack of ads or subscription fees.  Over the years, its education-first ethos hasn’t changed. “I came from a for-profit world,” Khan explains, referencing his hedge-fund past. “I don’t like organizations that are a little bit like, we’re just trying to help the world, but by the way, we’ll give you a return too. We said, look. This is first and foremost about….reaching people and helping them reach their potential.”

This is nothing short of revolutionary. It’s common practice nowadays for makeup gurus, high-trafficking Twitter accounts and even six-second Vine stars to monetize their views. And as the internet evolves, Khan Academy’s not-for-profit stance becomes more and more radical. To exist in such a commodified landscape—with a physical office in Silicon Valley, no less—and still choose, daily, to flout convention, feels a bit like flipping the bird to the rulebook. Offering high-quality schooling to the world’s poorest at the same time the rich pay up to $1250 an hour for tutoring is no less than a political statement.

His motivation stems back to adolescence. “If you go way back to high school, I’d always wonder why I’d have friends—we’ve all experienced this—who were doing just fine in seventh or eighth grade, and they’d get to high school and then all of a sudden, in an algebra class or physics class or something, they’d start hitting a wall. These are peers who can beat you at chess or solve a brainteaser better than you—why is this happening?” Simply put, he wants the world to reach its full potential. “There were some people in Silicon Valley who wanted to fund [Khan Academy] and start an EdTech company. That was tempting, but by the second or third conversation, it became a little bit… not what I wanted. I was getting a lot of psychic reward and enjoyment from seeing people around the world getting value, and I didn’t want to put any barriers on any of the content.”  Khan Academy ads read You Can Learn Anything. And that’s really all he wants to see.

But he’s not ready to start burning down the private sector. “For the most part, I think markets work. But there’s parts of society where markets fail. And that’s where nonprofits should step in. Education is a place that’s not well-suited for markets. The people who are the consumers are different from the people who are payers who are different from people who are decision makers.”

Khan knows he occupies a strange space in the American arena. At the start of his venture, all his peers—hedge fund managers and Silicon Valley entrepreneurs—were initially utterly confounded by his goal. “My hedge fund manager said, hey, guys, you’re gonna have a hard time,” he laughs. “Starting a nonprofit that is around free content—frankly, a lot of donors and philanthropists didn’t really understand it. I for sure had moments where I was wondering what I was doing. You can take comfort if you can at least point to other people who have gone down similar roads, but this was a very non-trodden path.”

The future of Khan’s little Foundation? More teaching, in more places. And always free. “The big vision here is… world class education for anyone, anywhere. If you don’t have access to a school, Khan Academy can be a place where you can self-educate yourself, if you still have access to a low-cost device. If you do have access to a school, we can hopefully supercharge that. Students can learn content at their own time and pace, [and] class time is freed up so that we have more human to human interactions.”

Over the phone, voice crackly and muffled, he dreams without inhibition. “Over the next three, four, five years, you’re going to see the number of subjects on Khan Academy increase by a factor of 10. We’re gonna have the humanities and the sciences. You’re gonna see exercises, and projects, and ways to write papers. You’re also going to see that being connected to real-life outcomes.”

And along the way, the trademark Khan Academy feel will not be lost—that genial patter that charmed young Nadia, then the Internet, so long ago. Warm, chattery, like an older cousin sitting across from you at the kitchen table. “This is something we’re working on as we speak. Tone is really important. We even have a little rubric that’s made up. Then we have some stuff about—are you really getting into the heart of the intuition for what’s going on? I definitely push our team. I say, look. If you can’t connect those dots, take some time researching.”

Maybe saving the world starts like this—with a cousin hunched over in their closet, muttering trigonometric functions into a cheap Lenovo microphone. Or the simple desire to do good, with no payback. Or a leap of faith. Sal Khan has bucked the zeitgeist of Silicon Valley, Wall Street, and the internet as a whole. Reflecting back on the moment Seldon’s Foundation emboldened him to make his own attempt towards educating humanity, he says, “[This] was such a grand idea, but at the same time, there was nothing about it that said it couldn’t happen.

And so I said, you only live once! Let’s go for that.”