Wiliam Poundstone's book The Doomsday Calculation takes a look at a mathematical approach to predicting the human race could end in 760 years. Photo / Getty Images
A book titled The Doomsday Calculation is taking a new look at a mathematical approach to predicting virtually anything within a 50 per cent likelihood, including when the human race will end.
Author William Poundstone has employed the Copernican method developed by Princeton University astrophysicist J Richard Gott III to estimate a 50 per cent chance the human race will cease to exist within roughly 760 years.
The method is said to work to predict the likely length of existence of anything of an uncertain duration so long as it's being encountered at a random point in time.
"Obviously, if you have any specific information affecting the life span of, say, the human race, or a class of stars, you can estimate its life span more realistically," Gott told the New York Times in 1993.
"But this statistical method allows you to make at least a rough estimate of a life span without knowing anything more than how long something has existed."
Poundstone explained the Copernican method behind his estimation of the end of humanity as we know it in a piece published by Vox.
"Demographers have estimated the total number of people who ever lived at about 100 billion. That means that about 100 billion people were born before me," he said.
"Currently, about 130 million people are born each year. At that rate, it would take only about 760 years for another 100 billion more people to be born."
"That's the basis of the claim that there's a 50 percent chance that humans will become extinct within about 760 years. The flip side of the claim is there's also a 50 percent chance we'll survive past 760 years, possibly long past that."
The Copernican method which Poundstone used to arrive at this figure is based on the Copernican principle, which says the Earth is not the centre of the universe.
Gott took that idea first known to be asserted by Copernicus, the great Renaissance astronomer, and applied it to humanity's position in time, relative to other things.
Doing this, he came up with the notion that knowing how long something has already existed can be a guide to estimating how long it will continue to exist.
In 1969, soon after graduating from Harvard with a physics degree, Gott used this method to predict the demolition of the Berlin Wall. He estimated that there was a 50 per cent chance the wall would come down no later than 24 years from that day, but that it would stand for at least two and two-thirds years more.
The demolition of the wall officially began on June 13, 1990, roughly 21 years later.
Gott reasoned that no matter how long the Berlin Wall existed, there would be a point in time that marks the 25 per cent point in the lifeline of the wall and one that marks the 75 per cent point in the lifeline of the wall.
Poundstone wrote "now take a deep breath. Imagine that a tourist wanted to make this prediction: "The future duration of the Berlin Wall will be between one-third and three times as long as its past duration."
"Gott made that prediction, except that he also made use of the knowledge that the wall was then eight years old."
Since the wall had existed for eight years at that point, Gott reasoned the wall would exist for between two and two-thirds more years and 24 more years, and that this would be true for half of the days of the Berlin Wall's existence.
Poundstone wrote "Gott reasoned that this prediction had a 50 per cent chance of being right. You may feel that 50 percent is too wishy-washy and Gott just got lucky"
"To achieve 95 percent confidence, you'd make a diagram with the shaded region covering the middle 95 per cent of the bar. The prediction range would be wider (from 1/39 to 39 times the past duration). Had Gott used this formulation, his prediction for the wall's ceasing to exist would have been 0.21 to 312 years after his visit. This is less impressive, given the extremely wide range — but it would have been correct, too."
Using his own method in 1993, Gott estimated the end of humanity with 95 per cent probability of accuracy. He wrote about it in a scientific journal called Nature.
"Making only the assumption that you are a random intelligent observer, limits for the total longevity of our species of 0.2 million to 8 million years can be derived at the 95 [percent] confidence level," Gott said, in the abstract for the article.
"Further consideration indicates that we are unlikely to colonise the Galaxy, and that we are likely to have a higher population than the median for intelligent species."
To read more about Poundstone's analysis of the method and how he applies it, 'The Doomsday Calculation' is available for purchase now on Amazon.