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Is the Doomsday Argument (probability) valid?
Posted on 5/28/22 at 7:39 pm
Posted on 5/28/22 at 7:39 pm
(Edit: Note, I added more descriptive quotes pulled from the Wikipedia in follow-up comments down towards the bottom of the first page that elaborate a bit more on what is going on in the calculations.)
From Wikipedia
From Wikipedia
quote:
The Doomsday argument (DA) is a probabilistic argument that claims to predict the future number of members in the human species given an estimate of the total number of humans born so far.
quote:
It was first proposed by the astrophysicist Brandon Carter in 1983,[1] from which it is sometimes called the Carter catastrophe; the argument was subsequently championed by the philosopher John A. Leslie and has since been independently discovered by J. Richard Gott[2] and Holger Bech Nielsen.[3] Similar principles of eschatology were proposed earlier by Heinz von Foerster, among others. A more general form was given earlier in the Lindy effect,[4] in which for certain phenomena the future life expectancy is proportional to (though not necessarily equal to) the current age, and is based on decreasing mortality rate over time: old things endure.
quote:
If Leslie's figure[5] is used, then 60 billion humans have been born so far, so it can be estimated that there is a 95% chance that the total number of humans N will be less than 20 × 60 billion = 1.2 trillion. Assuming that the world population stabilises at 10 billion and a life expectancy of 80 years, it can be estimated that the remaining 1140 billion humans will be born in 9120 years. Depending on the projection of world population in the forthcoming centuries, estimates may vary, but the main point of the argument is that it is unlikely that more than 1.2 trillion humans will ever live.
quote:
Robin Hanson's paper sums up these criticisms of the DA: All else is not equal; we have good reasons for thinking we are not randomly selected humans from all who will ever live.
This post was edited on 5/28/22 at 9:51 pm
8
Posted on 5/28/22 at 7:41 pm to UndercoverBryologist
Most posters here don't know the difference between loose and lose 
Posted on 5/28/22 at 7:44 pm to UndercoverBryologist
I can argue that it will be 1.4 trillion people.
Or 2.8 trillion.
What does it matter and how can you "prove" you'll be correct?
Or 2.8 trillion.
What does it matter and how can you "prove" you'll be correct?
Posted on 5/28/22 at 7:45 pm to Mason Dixon Swine
I guess I shouldn’t expand this topic to a deep dive of the Bayesian statistics at play then.
Posted on 5/28/22 at 7:48 pm to East Coast Band
quote:
What does it matter and how can you "prove" you'll be correct?
Well, East Coast Band asked for it:
A Third Route to the Doomsday Argument
Posted on 5/28/22 at 7:50 pm to Mason Dixon Swine
quote:
Most posters here don't know the difference between loose and lose
Why don't you loose the attitude
Posted on 5/28/22 at 7:51 pm to Mason Dixon Swine
quote:
Most posters here don't know the difference between loose and lose
Someone is gonna loose their mind on that one.
Posted on 5/28/22 at 7:54 pm to UndercoverBryologist
Probably a good thing philosophers are tackling this problem; leaves them less time to muck shite up.
Posted on 5/28/22 at 7:56 pm to Huey Lewis
quote:
Why don't you loose the attitude
One could say he already loosed the attitude.
Posted on 5/28/22 at 7:56 pm to UndercoverBryologist
Is this in the Bible?
Posted on 5/28/22 at 7:58 pm to UndercoverBryologist
Yeah but how does Sabes Que's unhealthy hatred of Mike Tyson factor into that?
Posted on 5/28/22 at 8:01 pm to Saintsisit
quote:
Yeah but how does Sabes Que's unhealthy hatred of Mike Tyson factor into that?
If Monty Hall says Mike Tyson is behind one of 3 doors, and you initially choose door 2, and Hall shows you a goat behind door 1 and asks if you would like to change your guess, you should switch to door 3...
...at that point you can punch Mike Tyson in the mouth for all I care because there’s a 67 percent chance he’s behind that door now.
Posted on 5/28/22 at 9:28 pm to UndercoverBryologist
quote:
60 billion humans have been born so far, so it can be estimated that there is a 95% chance that the total number of humans N will be less than 20 × 60 billion = 1.2 trillion.
Why does an estimate of 60 billion humans ever born mean that less than 20x that will ever be born?
Posted on 5/28/22 at 9:36 pm to olgoi khorkhoi
quote:
Why does an estimate of 60 billion humans ever born mean that less than 20x that will ever be born?
There’s some equations, which are little over my head (even with 2 semesters of graduate-level statistics on my transcript), but more officially describe what is going on.
But more descriptively, the Wikipedia article linked above describes the situation thusly
quote:
Assume for simplicity that the total number of humans who will ever be born is 60 billion (N1), or 6,000 billion (N2).[6] If there is no prior knowledge of the position that a currently living individual, X, has in the history of humanity, we may instead compute how many humans were born before X, and arrive at (say) 59,854,795,447, which would roughly place X amongst the first 60 billion humans who have ever lived. It is possible to sum the probabilities for each value of N and therefore to compute a statistical 'confidence limit' on N. For example, taking the numbers above, it is 99% certain that N is smaller than 6,000 billion.
Posted on 5/28/22 at 9:36 pm to olgoi khorkhoi
yeah there's an assumption here that isn't clearly stated in the OP. I havent clicked the link yet
Posted on 5/28/22 at 9:36 pm to castorinho
quote:
yeah there's an assumption here that isn't clearly stated in the OP. I havent clicked the link yet
CastorOhio, please see above.
Posted on 5/28/22 at 9:39 pm to UndercoverBryologist
More from the Wikipedia article:
quote:
Denoting by N the total number of humans who were ever or will ever be born, the Copernican principle suggests that any one human is equally likely (along with the other N - 1 humans) to find themselves at any position n of the total population N, so humans assume that our fractional position f = n/N is uniformly distributed on the interval [0, 1] prior to learning our absolute position. f is uniformly distributed on (0, 1) even after learning the absolute position n. That is, for example, there is a 95% chance that f is in the interval (0.05, 1), that is f > 0.05. In other words, we could assume that we could be 95% certain that we would be within the last 95% of all the humans ever to be born. If we know our absolute position n, this argument implies a 95% confident upper bound for N obtained by rearranging n/N > 0.05 to give N < 20n.
This post was edited on 5/28/22 at 9:47 pm
Posted on 5/28/22 at 9:39 pm to UndercoverBryologist
quote:
Depending on the projection of world population in the forthcoming centuries, estimates may vary, but the main point of the argument is that it is unlikely that more than 1.2 trillion humans will ever live.
What does Vegas say?
Posted on 5/28/22 at 9:44 pm to UndercoverBryologist
One last quote pulled from the Wikipedia article:
quote:
This is the simplest Bayesian derivation of the Doomsday Argument: The chance that the total number of humans that will ever be born (N) is greater than twenty times the total that have been is below 5%
Posted on 5/28/22 at 11:13 pm to UndercoverBryologist
quote:
guess I shouldn’t expand this topic to a deep dive of the Bayesian statistics at play then.
I am curious how they derived that 1.2 Trillion population figure...
Eta after reading it there's a couple of huge assumptions, mainly assuming just out of the blue that someone, anyone knows where they fall in the absolute placement of all humanity. In other words, every person before you could make the same argument.
This post was edited on 5/28/22 at 11:18 pm
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