Imagine a powerful being of your choice casting this spell on Earth:

  1. Earth can hold only 8 billion people
  2. If a child is being born and this child breaks the 8 billion rule, this happens:
  3. Wait 30 minutes. If someone else dies in this time, then everything is OK
  4. If not, take every human older than 32 minutes, and randomly kill one

If step 4 happens, such a person always dies by a sudden heart attack. If they cannot have a heart attack, they simply stop breathing. If they cannot stop breathing, their brain will simply stop working.


 22:00:00.000 UTC: Earth population: people, waiting...
 22:00:00.015 UTC: Live child (A) is being born in Pakistan
 22:15:00.389 UTC: Live child (B) is being born in USA
 22:25:13.618 UTC: Someone in Mongolia dies of age. Child A is resolved, Child B still pending
 22:32:00.015 UTC: Treshold for Child A, it can be given to random pool
 22:45:00.389 UTC: Child B is still unresolved, start random search...
 22:45:00.390 UTC: A hunter in Siberia gets heart attack and dies
 22:45:00.391 UTC: Earth population: people, waiting...
 22:50:05.850 UTC: Plane crashes in China. 190 people dead. Next 190 children can be born without killing anyone extra

For the scope of this question:
Alive == Brain activity.
Dead == no brain activity.

So if someone manages to survive a heart attack AND lung failure, their brain will simply shut off. So, you can keep their body "alive", but take for granted that such a person will never wake up (and they are taken out from the Earth random pool, because they are dead).

The question: Will humanity ever find out that such a rule is in place?

It is estimated, that we will hit 8 billion people milestone by the year 2026.

I know it is safe to assume that in (say) the next 10 year, people will somewhat realise that something weird goes on. But will they be able to pick this magical link?

And what would help them to do so? Do I have to create an alternate Earth, where there is more magic than just this one?

  • 2
    $\begingroup$ How would the randomly chosen people die ? Always with an heart attack like in your example or not ? A heart attack plague could help them understand what's happening (They do in Death Note). $\endgroup$
    – Tyrabel
    Sep 3, 2015 at 18:47
  • $\begingroup$ Are people randomly chosen from different locations and age groups? $\endgroup$
    – HDE 226868
    Sep 3, 2015 at 18:53
  • $\begingroup$ People are chosen randomly all over the world. And, as stated in the question: If you cannot kill because of heart attack, try to kill because of lung failure. And if you cannot kill because of lung failure, turn off their brain $\endgroup$ Sep 3, 2015 at 18:57
  • 1
    $\begingroup$ It's interesting to think about further reactions to people realizing this is happening - I foresee draconian birth rate laws, combined with global wars to enforce them. Which will in fact solve the problem, if not in exactly the expected manner. $\endgroup$ Sep 3, 2015 at 19:07
  • 1
    $\begingroup$ There are some philosophers who would argue you can never say with complete certainty that one thing caused another. I believe Sherlock Holmes would only accept a magical cause after ruling out all other options. So people might know what's going on, but the answer to why will take a lot more work, if it can ever be found. $\endgroup$ Sep 3, 2015 at 19:12

2 Answers 2


Something will send up a flag, if the population count appears to stall at 8,000,000,000. At first I thought it will likely take a few years past the mark to notice that overall population isn't increasing and maybe one or two more to narrow down a close number. However...

Looked it up it appears that the average death per day is 7.89/1000 people, the average births/day is around 20/1000. So there are over twice as many births as deaths/1000 people on the planet. Using these numbers once we hit 8,000,000,000 people the death rate will automatically more than double. That will be a huge flag for statisticians. And when the birth rate and death rate remain steady and equal (unless a large war or other event INCREASES the death rate) it will be pretty obvious that SOMETHING is going on artificially limiting the population.

The scary thing is that once the pattern is noticed, wars and genocide might be waged in order to 'choose' who will die, not us, but THEM!

EDT: One last thing, if we discovered that being off Earth negates the 'spell', meaning it doesn't matter how many people are living on the moon, then we will start working hard at getting off this ball and colonizing the solar system.

  • 1
    $\begingroup$ Interestingly, a large war probably wouldn't affect the death rate in this scenario. Unless that war pushed the global death rate (sans deaths from magic) over the birth rate, it would merely mean that people would die from bullets instead of heart attacks. $\endgroup$
    – ckersch
    Sep 3, 2015 at 19:17
  • $\begingroup$ @ckersch right, it would have to be a BIG event. $\endgroup$
    – bowlturner
    Sep 3, 2015 at 19:18
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    $\begingroup$ Actually, I think we could go along for quite a while before this is discovered. Any statistician seeing that creepy statistical irregularity would have a heart attack, giving us a little more wiggle room on the death count! $\endgroup$
    – Cort Ammon
    Sep 3, 2015 at 19:26
  • 1
    $\begingroup$ As a more serious addition, I'd consider the famous quote "Real scientific discoveries do not sound like a philosopher jumping out of the bathtub and running down the streets naked yelling 'Eureka! Eureka!' Real scientific discoveries more often sound like, 'Hmm. That's kind of funny.'" $\endgroup$
    – Cort Ammon
    Sep 3, 2015 at 19:28
  • $\begingroup$ Does anyone know exactly how many people on Earth? I'd think the 8,000,000,000 limit would not be discovered until after several rounds of censuses are done in all the countries in the world, some of which take place several years apart, others which are not done at all. All we'd have to go on is the sudden increase in heart attacks which has brought the death rate up to be = the birth rate. And I think it would be some time before that is attributed to a Divine limit by the serious scientific community... $\endgroup$
    – komodosp
    Sep 4, 2015 at 12:21

The first sign that something fishy is going on probably will not be the stable population but rather the sudden, sharp, unexplainable increase in healthy people getting un-curable heart attacks for no apparent reason.

Since medical statistics are kept by all civilized countries, which normally also have the highest chance of saving people (especially young ones) from heart attack, you would probably notice something fishy going on really fast.

Once you compare statistics and do calculations, it should not be very hard (especially after a few months/years) to reach the conclusion that the number of random heart attacks correlates strongly with population in each country, which in turn leads to the conclusion that it's a global thing.

From there, you can count backwards to when it started to happen all of a sudden using existing statistics, and then link it pretty easily to the birthrate and come to the conclusion that it must be related to people being born vs people dying.

Personally I'll give it half a year before we figure it out, but much longer before we believe it and even longer before we can convince other people that something magical is happening.

  • $\begingroup$ I'm not sure I follow your logic on counting it back and thus linking it to birthrate. Sure, you might be able to find when it started but I would be surprised if you could link it to birthrate. There's two reasons why I think this, firstly I doubt the data is good enough to notice that there is a strong link between the two. Secondly because correlation does not equal causation. Even if people did notice that there is this correlation no sane scientist would suggest that people are dying because people are being born without a good scientific theory. $\endgroup$
    – Chris
    Sep 4, 2015 at 11:29

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