From Reddit: Parents Of Children Who Claim To Have Had Past Lives, What Did They Tell You?. Some sample comments:

When he was 6 years old my son described in great detail my grandmother’s house he never been to. This was in 1986 or so, pre-internet. There are no pics of the place that I’m aware and no one owned a camcorder in our family, so video is out of question either. It’s a small house with red roof and a purple door (grandma painted the door every couple of years). He described all of it – that it had one big room with a fireplace across from the window, he explained where the doors are located, how there always were some boxes under the stairs, that there always was a faint smell of apples in the house (grandma ran a small time apple sauce business). That there was this cat almost completely white with a black spot around his right eye (that’s mr. Whiskers, my grandma’s cat!). My grandma and Whiskers both died in 1977, 3 years before my son was born. To this day I can’t fathom it and can’t even get a remotely sane explanation on how does he know all this. I never told him about it, my wife has never met my grandma and never been to her house and in 1986 we were stationed in Germany, so none of my old friends could have reached my son, so this is definitely not someone’s prank. Best part of this is my son says he doesn’t remember telling me that, but my wife heard him saying that too, so if definitely happened!

And from Reddit, What Is The Creepiest “Glitch In The Matrix” You’ve Encountered?:

When I was in school I had this hippie teacher who would always tell us that the universe can help if you just ask it. She told us one time her daughter had lost something very important and when she asked the universe to help she suddenly had a massive pulling feeling towards the sink. She walks over and immediately stuck her hand down into the garbage disposal and pulled the item out in perfect condition. So I think it’s total bullshit of course, but later that day I was searching for a thin little booklet that I really, really needed for school. I spent 3 hours looking for it and had no luck. Finally out of frustration I almost sarcastically said, “I need your help universe.” I immediately walked over to this bookcase filled with books from my step dad. I had never once used this shelf or any book on it. I grab a random book I’ve never seen from the middle of a huge pile. I open it to somewhere around page 200 and right there is my booklet smashed in between the pages. It was incredibly thin so you couldn’t even tell there was anything in there if you looked at it from another angle. I’m sure there’s a good explanation, but it’s been well over a decade and I still remember the incredibly freaky vibe I got the moment I saw the book.

I don’t believe in reincarnation or paranormal forces. When I read stories like this, my first impulse is to try to think of reasonable explanations or ways they could be a coincidence. Maybe some kids have instinctive talent at that sort of cold-reading thing TV psychics do sometimes. Maybe your unconscious can remember where you put a booklet and then repress it from the conscious mind for some reason.

But these kinds of claims are often themselves far-fetched. If I told you in normal conversation, unrelated to compelling reincarnation theories, that kids have a natural talent at cold reaading, you’d scoff and demand proof. And it’s not just reincarnation and booklet-finding. If you read Reddit enough, you’ll find hundreds of equally compelling stories of telepathic contact, cryptid sightings, UFOs, et cetera.

So. Alternate hypothesis. About one million people view Reddit every day. Let’s assume 10% of those see threads like the above – which were pretty popular and which I think both made it to the front page. That’s 100,000 people. Now let’s assume that even 1/10,000 people on the Internet are annoying trolls, which is maybe the easiest assumption we’re ever going to have to make. If each of those annoying trolls posts one fake story to a thread like that for the lulz, that’s enough for ten really convincing stories per thread – which is really all there are, the other fifty or sixty are just the usual friend-of-a-friend-had-a-vague-feeling stuff.

(it’s true that in a site read by a million people, there will also be far more people who have experienced a genuine one-in-a-million coincidence, but that shouldn’t scale nearly as quickly; after all, liars can invent coincidences way more far-fetched than the sheer numbers would allow)

This hypothesis seems obviously right. If I ask “what’s the chance that at least one in ten thousand Internet users is an annoying troll?” you laugh hysterically and tell me that nobody has even invented numbers that high. It perfectly explains mysterious events that would otherwise require impossible coincidences or weird theories about hidden brain functions. So why is it so hard to make myself believe?

I think part of it is a failure of scale. Reddit looks a lot like a normal forum or blog comment section, the sort of BBS I used to go on as a kid with twenty or thirty regulars who would dominate all the discussions. If indeed 1/10,000 people is the sort of jerk who would make up a story like this just to troll people (or even 1/1,000 or 1/100 people), the chance that I’d run into them on my little BBS/comment section/Dunbar-number-group is pretty low, and I can safely ignore the possibility that five different crazy paranormal comments are all by pathological liars. It’s only when you get a place like Reddit, which manages to feel like a community while also having a million readers a day, that you have to start thinking about these things.

This suggests a more general principle: interesting things should usually be lies. Let me give three examples.

I wrote in Toxoplasma of Rage about how even when people crusade against real evils, the particular stories they focus on tend to be false disproportionately often. Why? Because the thousands of true stories all have some subtleties or complicating factors, whereas liars are free to make up things which exactly perfectly fit the narrative. Given thousands of stories to choose from, the ones that bubble to the top will probably be the lies, just like on Reddit.

Every time I do a links post, even when I am very careful to double- and triple- check everything, and to only link to trustworthy sources in the mainstream media, a couple of my links end up being wrong. I’m selecting for surprising-if-true stories, but there’s only one way to get surprising-if-true stories that isn’t surprising, and given an entire Internet to choose from, many of the stories involved will be false.

And then there’s bad science. I can’t remember where I first saw this, so I can’t give credit, but somebody argued that the problem with non-replicable science isn’t just publication bias or p-hacking. It’s that some people will be sloppy, biased, or just stumble through bad luck upon a seemingly-good methodology that actually produces lots of false positives, and that almost all interesting results will come from these people. They’re the equivalent of Reddit liars – if there are enough of them, then all of the top comments will be theirs, since they’re able to come up with much more interesting stuff than the truth-tellers. In fields where sloppiness is easy, the truth-tellers will be gradually driven out, appearing to be incompetent since they can’t even replicate the most basic findings of the field, let alone advance it in any way. The sloppy people will survive to train the next generation of PhD students, and you’ll end up with a stable equilibrium.

The weird thing is, I know all of this. I know that if a community is big enough to include even a few liars, then absent a strong mechanism to stop them those lies should rise to the top. I know that pretty much all of our modern communities are super-Dunbar sized and ought to follow that principle.

And yet my System 1 still refuses to believe that the people in those Reddit threads are liars. It’s actually kind of horrified at the thought, imagining them as their shoulders slump and they glumly say “Well, I guess I didn’t really expect anyone to believe me”. I want to say “No! I believe you! I know you had a weird experience and it must be hard for you, but these things happen, I’m sure you’re a good person!”

If you’re like me, and you want to respond to this post with “but how do you know that person didn’t just experience a certain coincidence or weird psychological trick?”, then before you comment take a second to ask why the “they’re lying” theory is so hard to believe. And when you figure it out, tell me, because I really want to know.