The Doomsday Scenario, also known as the Copernican Principle, refers to a framework for thinking about the death of humanity. One can read all about it in a recent book by science writer William Poundstone. The principle was popularized mainly by the philosopher John Leslie and the physicist J. Richard Gott in the 1990s; since then variants of it have have been cropping up with increasing frequency, a frequency which seems to be roughly proportional to how much people worry about the world and its future.
The Copernican Principle simply states that the probability of us existing at a unique time in history is small because we are nothing special. We therefore must exist roughly close to half the period of our existence. Using Bayesian statistics and the known growth of population, Gott and others then calculated lower bounds for humanity’s future existence. Referring to the lower bound, their conclusion is that there is a 95% chance that humanity will go extinct in 9120 years.
The Doomsday Argument has sparked a lively debate on the fate of humanity and on different mechanisms by which the end will finally come. As far as I can tell, the argument is little more than inspired numerology and has little to do with any rigorous mathematics. But the psychological aspects of the argument are far more interesting than the mathematical ones; the arguments are interesting because they tell us that many people are thinking about the end of mankind, and that they are doing this because they are fundamentally pessimistic. This should be clear by how many people are now talking about how some combination of nuclear war, climate change and AI will doom us in the near future. I reject such grim prognostications because they are mostly compelled by psychological impressions rather than by any semblance of certainty.
A major reason why there is so much pessimism these days is because of what the great historian Barbara Tuchman once called ‘Tuchman’s Law’; Tuchman’s Law states that the impression that an event leaves in the minds of observers is proportional to its coverage in the newspapers. Tuchman said this in 1979, and it has become a truism today because of the Internet. The media is much more interested in reporting bad things that happened rather than good things that did not happen, so it’s easy to think that the world is getting worse every day. The explosion of social media and multiple news sources have amplified this sensationalism and selection bias by gargantuan proportions. As Tuchman said, even if you may be relentlessly reading about a troubling phenomenon like child kidnapping or mass shootings, it is exceedingly rare that you will come home on any given day having faced such calamities.
In this trivial sense I agree with Bill Gates, Hans Rosling, Steven Pinker and others who have written books describing how by almost every important parameter – for instance child mortality, women and minority rights, health status, poverty, political awareness, environmental improvement – the world of today is not just vastly better than that of yesterday but has been on a steep and steady curve of improvement since medieval times. One simply needs to pick up any well-regarded book on medieval history (Tuchman’s marvelous book “The Distant Mirror” describing the calamitous 14th century will do the job) to realize how present human populations almost seem to live on a different planet as far as quality of life is concerned. This does not refute the often uneven distribution of progress, nor thus it tell us that every improvement that we have seen is guaranteed, nor this it say we should rest on our laurels, but it does give us more than enough rational cause for optimism.
Sometimes the difference between optimism and pessimism is simply related to looking at the same data point in two different ways. For instance, take as a reference date the year that the US Supreme Court legalized same-sex marriage – 2015. Now go back a hundred years, to 1915. Even in the United States the world of individual rights was stunningly different from now. Women could not vote, immigration from non-European countries was strongly discouraged and restricted, racism against non-white people (and even some white people such as Catholics) was part of the fabric of American society, black people were actively getting lynched in the south and their civil rights were almost non-existent, abortion was illegal, gay people would not dream of coming out of the closet and anti-Semitism was not only rampant but institutionalized in places like Ivy League universities.
It is downright incredible that, only a hundred years later, every single one of these barriers had fallen. Not one or two or three, but every single one. I cannot see how this extraordinary reversal of discrimination and inequality cannot lead to soaring optimism about the future. Now, two people might look at this fact in two different ways. One might say, “It took 228 years since the writing of the US Constitution for these developments to transpire”, while another person might say, “It took only a hundred years from 1915 for these developments to transpire”. Which perspective do you choose since both are equally valid? I choose the latter, not only because it points to optimism for the future but to informed optimism. There has been a tremendous raising of moral consciousness about equal treatment of all kinds of groups in the last one hundred years, and if anything, the strong, unstoppable waves of progressivism on the Internet promise that this moral elevation will continue unabated. There are effectively zero chances that women or minorities will lose the vote for instance. The price of liberty is eternal vigilance, not eternal pessimism.
What about those four horsemen of the apocalypse, now compressed into the three horsemen comprising nuclear war, AI and climate change, that seem to loom large when it comes to a dim view of the future of humanity? I believe that as real as some of the fears from climate change, nuclear war and AI are, they are exaggerated and not likely to impact us the way we think.
First, climate change. There are many deleterious impacts of human beings on the environment, of which global warming is an important one and likely the most complicated to predict in its details. It is harder to predict phenomena like the absorption of carbon dioxide by the biosphere and the melting of glaciers based on computer models than it is to understand and act on phenomena like ocean acidification, deforestation, air pollution and strip mining. Sadly, discussions of these topics are often lost in the political din surrounding global warming. There is also insufficient enthusiasm for solutions such as nuclear energy and solar power that can make a real impact on energy usage and fossil fuel emissions. On the bright side, support for fighting climate change and environmental degradation is more vociferous than ever, and social media thankfully has played an important role in generating it. This support is similar to the support that early 20th century environmentalists lent to preventing creatures like the American buffalo and whales from going extinct. There are good reasons to think that whatever the real or perceived effects of climate change, it will not cease to be a publicly important issue in the future. But my optimism regarding climate change does not just come from the level of public engagement I see but from the ability of humans to cope; I am not saying that climate change will pose no problem, but that one way or another humans will find solutions to contain or even eliminate those problems. Humans survived the last ice age at dangerously low levels of population and technological capability compared to today, so there is little reason to think that we won’t be able to cope. Some people worry whether it is worth bequeathing the uncertain world of tomorrow to our children and grandchildren. My belief is that, considering the travails that humanity successfully faced in the last thousand years or so, our children and grandchildren will be more than competent to handle whatever problem they are handed by their predecessors and the planet.
Second, nuclear war. The world’s nuclear arsenals have posed a clear and present danger for years. However, deterrence – as fragile and fraught with near misses as it is – has ensured that no nuclear weapon has been exploded in anger for almost 75 years. This is an almost miraculous track record. Moreover, while the acquisition of dirty bombs or nuclear material by non state actors is a real concern, the global nuclear stockpile has been generally quite secure, and there are enough concerned experts who continue to monitor this situation. Since the end of the Cold War, both the United States and Russia have significantly reduced their stockpiles, although both countries should go to still lower numbers. The detonation of even a low yield nuclear weapon in a major city will be a great tragedy, but it will not have the same effects as the global thermonuclear war whose threat the world labored under for more than fifty years. In 1960, Herman Kahn wrote “On Thermonuclear War”, a controversial book that argued that even a major thermonuclear war would not mean the end of humanity as most people feared. Part of Kahn’s analysis included calculations on the number of deaths and part included historical evidence of human renewal and hope after major wars. While the book was morbid in many details, it did make the point that humanity is far more resilient than we think. Fortunately the scenarios that Kahn described never came to pass, and the risk of them happening even on a small scale are now far lower than they ever were.
Finally, AI seems to be perhaps the prime reason for the extinction of humanity that many world and business leaders and laymen fear. Early fears centered on the kind of killer robots that dotted the landscape of science fiction movies, but recent concerns have centered on machines gradually developing intelligence and humans gradually ceding authority to them. But most AI doomsday scenarios are speculative at best and contain a core of deep uncertainty. For instance, a famous argument made by Nick Bostrom described a scenario called the AI paperclip maximizer. The idea is that humanity creates an AI whose purpose is to create paperclips. The AI will gradually single-mindedly start making paperclips out of everything, consuming all natural resources and rendering the human race extinct. This kind of doomsday scenario has some important assumptions built into it, among which is the assumption that such an AI can actually exist and wouldn’t have a failsafe built into it. But the bigger question is regarding the AI’s intelligence: any kind of truly intelligent AI won’t spend its entire time making paperclips, while any kind of insufficiently intelligent AI will be easily controlled by human beings or at least live with them in some kind of harmony. I worry much less about a paperclip AI than I do about humans gradually ceding thinking to fleeting sources of entertainment like social media.
But the real problem with any kind of doomsday scenario involving AGI (artificial general intelligence) is that it simply underestimates what it would take for a machine to acquire true human-like cognitive capabilities. One of the best guides to thinking about exactly what it would take for AGI to somehow take over the world is the technologist Kevin Kelly. He gives three principal reasons for the unlikelihood of this happening: one, that intelligence is along many axes, and even very intelligent human beings are usually intelligent along a few; second, that intelligence is not just gained through thinking alone but through experimentation, and that experimentation slows down any impact that a super-intelligence might have; and three, that any kind of AGI scenario assumes that the relationship between humans and their creations would be intrinsically hostile and fixed. Almost all such assumptions about AGI are subject to doubt, and at least a few of the conditions that seem to be necessary for AGI to truly dominate humanity seem to be both rate-limiting and unlikely.
Ultimately, most doomsday scenarios are based on predicting the future, and prediction, as Niels Bohr famously said, is very difficult, especially concerning the future. The most important prediction about the future of humanity will probably be the one that we are not capable of making. But in the absence of accurate prediction about the future, we have the past. And while the past is never a certain guide to the future, the human past in particular shows a young species that is almost infinitely capable of adaptation, empathy, creativity and optimism. I see no reason to believe this will not continue to be the case.