TECHNOLOGY REVIEW: The Doomsday Argument is the idea that we can estimate the total number of humans that will ever exist, given the number that have lived so far. This in turn tells us how likely it is that human civilisation will survive far into the future.
The numbers are not optimistic. Anthropologists think some 70 billion humans have so far lived on Earth. If we assume that we have no special status in human history, then simple probabilistic arguments suggest that there is a 95 per cent chance that we are among the last 95 per cent of humans that will ever be born. And this means there is a 95 per cent chance that the total number of humans that will ever exist will be less than 20 x 70 billion or 1.4 trillion.
These guys look at the scenario in which many civilisations have evolved throughout the universe, the so-called “universal doomsday” argument. “In that case, we should consider ourselves to be randomly chosen from all individuals in that universe or multiverse,” they say.
Now suppose that the world population stabilises at 10 billion and our life expectancy is 80 years, then the remaining humans will be born in the next 10,000 years. That’s not a long future for humanity. Today, Austin Gerig at the University of Oxford and a couple of pals put forward a new argument with a (slightly) happier ending.
These guys look at the scenario in which many civilisations have evolved throughout the universe, the so-called “universal doomsday” argument. “In that case, we should consider ourselves to be randomly chosen from all individuals in that universe or multiverse,” they say.
In the past, these universal arguments have been no more optimistic than the ordinary ones. They generally state that long-lived civilizations must be rare because if they were not, we would be living in one. What’s more, because long-lived civilizations are rare, the prospects for our civilisation ever becoming long-lived are poor.
This new approach approach allows Gerig and co to take a more fine-grained look at the odds that humanity will survive for much longer in future than it has existed in the past.
The results are complex but their main conclusion gives some reason for hope. “If [the number of existential threats] is not too large, the probability of long-term survival is about a few percent,” they say.
The numbers are not optimistic. Anthropologists think some 70 billion humans have so far lived on Earth. If we assume that we have no special status in human history, then simple probabilistic arguments suggest that there is a 95 per cent chance that we are among the last 95 per cent of humans that will ever be born. And this means there is a 95 per cent chance that the total number of humans that will ever exist will be less than 20 x 70 billion or 1.4 trillion.
These guys look at the scenario in which many civilisations have evolved throughout the universe, the so-called “universal doomsday” argument. “In that case, we should consider ourselves to be randomly chosen from all individuals in that universe or multiverse,” they say.
Now suppose that the world population stabilises at 10 billion and our life expectancy is 80 years, then the remaining humans will be born in the next 10,000 years. That’s not a long future for humanity. Today, Austin Gerig at the University of Oxford and a couple of pals put forward a new argument with a (slightly) happier ending.
These guys look at the scenario in which many civilisations have evolved throughout the universe, the so-called “universal doomsday” argument. “In that case, we should consider ourselves to be randomly chosen from all individuals in that universe or multiverse,” they say.
In the past, these universal arguments have been no more optimistic than the ordinary ones. They generally state that long-lived civilizations must be rare because if they were not, we would be living in one. What’s more, because long-lived civilizations are rare, the prospects for our civilisation ever becoming long-lived are poor.
This new approach approach allows Gerig and co to take a more fine-grained look at the odds that humanity will survive for much longer in future than it has existed in the past.
The results are complex but their main conclusion gives some reason for hope. “If [the number of existential threats] is not too large, the probability of long-term survival is about a few percent,” they say.
It's comforting to muse that we can actually know the future, and the likelihood of a predicted outcome. We guffaw when the weather anchor "gets it wrong," and somehow think that global warming means if the entire planet isn't becoming the Sahara Desert (and it snows somewhere), there's nothing to it. In the need for accuracy and truth, science revises itself through a rigorous process of peer review, and adherence to The Scientific Method. Modeling and probability always have a margin for error, so in reading the link, think of that.
One of the ways to "increase our odds" is addressing "existential threats" (meteors, nuclear war, pandemics, poverty), and becoming a space faring species. On "a few percent": Growing up under the "duck and cover" drills of the 60s during the Cold War (during which I never thought we had a snowball's chance), I'll TAKE that!
My Pascha post...
Physics arXiv: Universal Doomsday: Analyzing Our Prospects for Survival
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