An idea by a Highlands teenager has garnered worldwide attention and is now, six years later, the basis for a fledgling start-up.
At its heart is a simple question: how do you fix the often ugly world of online debate?
Kal Turnbull can't remember what presents he got for his 17th birthday, or what type of cake he had. If someone gave him a particularly amusing birthday card, the joke has long been lost to history.
However he does have one standout moment of that day in January 2013. Kal started a discussion group, or subreddit, on the social media site Reddit.
Change My View wasn't meant to shake up the world. It was simply the pet project of a curious guitar-playing teenager growing up in the Scottish Highlands near Inverness.
"I was very aware that I might have grown up in a bit of a small-town bubble," Kal told us recently while meandering down a path along the River Ness. "It's not that we all agreed on everything, we certainly had disagreements. It's just the sense that there's much more than this place.
"Being 17, I wasn't going to start up a website or a company. Reddit provided the perfect platform to try this idea out."
In its first iteration, Change My View was - and still is - fairly simple: users post an honestly-held belief, anything from politically provocative ("The case for reparations to African-Americans is strong", "Women already have equality") to the relatively unimportant but still extremely contentious ("Avengers: Endgame did not make any sense").
The posts cover a huge range of topics and political perspectives - and once they're live, other Reddit users are urged to argue against the proposition.
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What are the rules?
There are some basic ground rules: explain your reasoning, challenge the proposition, but don't be rude or hostile. Original posters are required to engage and to truly consider counter-arguments.
Kal's subreddit took off, growing to 100,000 members within a year and more than 700,000 today.
Six years later, what started as a side project has now become Kal's main occupation - and he's convinced it might just help solve a vexing problem of online life.
Many of us agree that the quality of most online conversations is dire. Facebook and Twitter are filled with angry shouting (or mindless agreement), people talking past each other, fallacious reasoning, and lies. And that's before you even get to the trolls, the propaganda, the fake news, and the disinformation.
Users are caught in filter bubbles and echo chambers, which they leave only to yell at their opponents and wage poorly-punctuated battles against their perceived enemies. Much of what passes for political discourse is either vigorous groupthink agreement or nasty sniping.
The inventor of the world wide web, Sir Tim Berners-Lee, recently put it like this: "Humanity connected by technology on the web is functioning in a dystopian way." In an open letter he decried the "outraged and polarised tone and quality of online discourse".
What's the answer?
Into this world has arrived ChangeAView.com, Kal's attempt to build on his subreddit through a website designed to extend his original idea.
"I think most people would agree that the current state of online discourse, if you spend five minutes on Twitter or Facebook, is surely not where we end up," Kal says. "This cannot be how things should be.
"We're trying to build a solution to that problem."
Kal started Change A View along two US-based co-founders. Structurally it resembles other tech start-ups and is a for-profit business - albeit one based amid the lochs of the Highlands rather than in Silicon Valley's suburban sprawl.
It also incorporates features that go beyond the capabilities of Reddit's platform. At the heart of the site is what's called the "delta system", named after the mathematical symbol denoting change. Deltas are awarded to particularly strong or persuasive arguments - ones that are likely to make users reconsider their positions.
The site is structured to try to provoke thoughtful, well-reasoned conversation, and reward users who demonstrate both mental flexibility and the ability to back up their views with evidence.
"Another thing that Change A View is trying to do is reframe our relationship to being wrong," Kal says. "It's not necessarily a negative thing. It doesn't have to be a humiliating thing. It's a chance to lose some ignorance, and perhaps gain some insight."
Will it work?
While he was involved with the subreddit, Kal ran it along with volunteer moderators. At the time, he was also studying for a degree in civil engineering at the University of Edinburgh and later, working a full-time job.
The new ChangeAView website (the name is subtly different from the subreddit's in order to avoid confusion) has attracted attention from tech bible Wired. And the larger idea has been given a boost from devoted followers, as well as people like former US President Barack Obama and Tesla boss Elon Musk.
True, although the changemyview subreddit is least likely to be clicked on by people who really should change their view https://t.co/DlVgSc3ZJJ— Elon Musk (@elonmusk) August 6, 2017
So how does he answer the Tesla CEO's scepticism - the idea that the people least likely to use the subreddit or the Change A View site are probably the ones who need it the most?
"I take the point that some people who are just not interested in considering other perspectives might not appreciate or use this place," he says.
"I think what we're trying to do though is we're trying to introduce a bit of a cultural shift," he continues. "That might not necessarily improve everything immediately.
"But over time, by having more considered discussions, those will eventually grow in a way that influences people... without even them using the website."
There's another criticism that comes to mind: what about situations where intellectual flexibility might not be a virtue? It might not have been a good idea if, for instance, Galileo or Gandhi had been swayed from their steadfast paths. But Kal, who is scrupulous about maintaining his own neutrality on controversial subjects, doesn't think that open-mindedness and determination are mutually exclusive.
"I don't think this is always about being open to your view being wrong," he says. "Sometimes it's just about understanding the other perspectives so you can change them more effectively."
ChangeAView launched in April and, as of yet, has no investors other than Kal and his co-founders. The company is up and running in part due to money from Jigsaw, the Google-owned tech incubator.
"We really got excited about talking to them because the way that they describe their mission is really core to our mission, which is let's help people who have different points of views and different perspectives have a civil debate," says Patricia Georgiou, Jigsaw's head of partnerships and business development.
"The more people with diverse points of views and diverse opinions are able to have a civil conversation, the more we have hope in moving society forward."
Kal's waking hours are devoted to thinking about the business and the tricky tasks of building investment and potential revenue streams, with the occasional break to wander around Inverness with visiting journalists.
He points out places he's played gigs with his former band and somewhat wistfully shows us around a guitar shop - there's not much time for music these days.
After an initial publicity bump, Change A View now has a relatively modest 5,000 members. The topics discussed on the site veer towards the serious and political, with something of an American slant: "Euthanasia should be legalized in all US States", "College is a right, make it free", "Boy Scout troops should not include girls".
But there's still room for some of the lighter arguments - for instance, someone recently posited: "Season 8 of Game of Thrones was great until the last episode." And a quick scroll through the often well-expressed comments confirms that, yes, some people are definitely changing their views.
"Seeing these moments where people are having discussions ... I just want to see this at scale," Kal says. "And we hope that that impact goes well beyond this website."
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