In Larry Niven’s Ringworld, the alien Puppeteers have secretly been selectively breeding humans for being lucky, which they believe (correctly) is actually a psychic probability manipulation ability. (This seems a little weird because natural selection already involves a lot of luck on the individual level, but let’s just roll with it.) They had concluded from Earth’s history that humans were already lucky, and they tried to enhance this trait by encouraging an overpopulated Earth of 18 billion people to set up a lottery for the right to have children (one of several allowed methods of qualifying).

Two hundred years later, the Puppeteer Nessus is recruiting people for a very dangerous mission to Ringworld. In order to ensure the mission’s success, he recruits an extremely lucky human named Teela Brown. Teela’s ancestors were all winners of the Birthright Lottery for the past five generations, and Nessus hopes that her good luck will help the entire mission survive.

However, the mission eventually goes badly, and Nessus decides that Teela wasn’t lucky after all because if she were, she wouldn’t have wound up on this very dangerous mission. Their pilot, Louis Wu, disagrees. He says that Teela’s luck simply doesn’t rub off on the people around her. In fact, if someone attacks them, they’re going to miss her, but that makes them more likely to hit the person standing next to her.

I’ve always thought Louis didn’t go far enough, though. He didn’t seem to recognize the full implications of the situation. Nessus was indeed wrong; Teela Brown was lucky, but she was even luckier than either of them seemed to realize. And that fact should terrify Nessus far more than if she wasn’t.

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By the end, it’s fairly obvious to the reader that Teela was lucky. Louis remarks that she looks like a klutz. She doesn’t look before she leaps, and she almost walks like a toddler and looks like she ought to be tripping over her own feet, except she doesn’t. She walks that way because she never learned to walk properly because she never trips over her own feet except in the rare cases when it helps her somehow.

The clue to what’s really going on with Teela Brown is right there in the first chapter. Any multi-generation winner would do for the Ringworld mission, but funnily enough, the Puppeteers can’t get a hold of any of them. By weird coincidences, they keep missing them, despite trying to talk to a lot of them. This is the evidence Nessus uses to determine that anyone who was really lucky would have avoided the mission, but look again at what he actually said:

“When we call, they are out. When we call back, the phone computer gives us a bad connection. When we ask for any member of the Brandt family, every phone in South America rings.”

Uh, one of these things is not like the others…

This is much bigger than the Brandt family or the other individual candidates. Here’s the thing about quantum mechanics, and if we’re talking psychic probability manipulation in fiction, there’s very likely a “quantum” in there: if one possibility is forbidden, the next most likely possibility is what will probably happen. This may seem obvious, but it’s not holding here. If the Brandt family’s luck said, “The Brandts are not going to Ringworld,” all it would have to do have them miss the Puppeteers’ calls like the rest of the candidates. I’m not sure any phone system then or now is even capable of dialing every number on the network at once. It’s certainly a much less likely malfunction, especially if it persists through presumed repair attempts. What’s going on?

The answer is simple. In fact, Nessus said it himself: humans were already lucky.

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There’s actually one more piece to the puzzle that we need to understand this. In the Known Space setting, famed pilot Beowulf Schaeffer discovered that the galactic core is “exploding”—or more precisely, a whole bunch of supernovae are exploding at once, creating a wave of deadly radiation that will wipe out all life in the galaxy. (Scientifically, this is less silly than it sounds, but still mostly wrong.) Although the danger is still 20,000 years away, humans are already concerned about what they’re going to do about it.

Well, the Puppeteers have an answer. They’re offering humans a better hyperdrive as payment for the Ringworld mission—a hyperdrive fast enough to escape the galaxy. It sounds like a good deal; except now, they’ve created a dangerous incentive.

Humans need this hyperdrive. That means they need the Ringworld mission to succeed. It’s going to take a lot of luck for that mission to succeed. And humans as a species are lucky.

One person’s or one family’s luck is never going to dial a billion phones at once because it doesn’t need to. They don’t gain anything by causing that, whether it can be traced back to them or not. But humanity as a whole does gain. It pushes the Puppeteers to work harder to recruit the one candidate they can find—the person who will give the mission the greatest chance of success.

My theory is that it wasn’t anything about the Brandt family that made every phone in South America ring. It was the collective luck of 18 billion humans on Earth, plus who knows how many more in the colonies, plus millions of winners of fewer generations of the Birthright Lottery, plus the several thousand five-generation winners—all conspiring to send the luckiest human who ever lived to Ringworld: the woman who has never suffered a financial setback, who’s never lost badly at gambling, who’s never had even a mildly bad breakup, who’s never broken a bone or suffered a serious injury, who never even learned how to avoid tripping and falling because she didn’t need to: Teela Brown.

And if Teela’s own luck is a hazard to the people around her, how much damage could an entire species’ worth of luck do?

Nessus is probably wishing he’d just stayed home right about now.