Bostrom, Nick

Nick is a philosopher and Director of the Future of Humanity Institute at the University of Oxford. He is also Chairman of the World Transhumanist Association and the Institute for Ethics and Emerging Technologies. Nick is known for his work on the anthropic principle (selection effect), the simulation argument (the possibility that we are living in a simulation), and various transhumant-related issues such as artificial intelligence, cloning, and mind uploading. Consider what he writes about the Doomsday Argument, which, briefly, is a probabilistic argument that claims to predict the total future lifetime of the human race given only our current estimate of the total number of humans born so far. According to the Copernican principle, we should always expect to find ourselves in rather mediocre positions, never at any extremes. Simply put, the Doomsday Argument says that supposing the humans alive today are in a random place in the whole human history timeline, chances are we are about halfway through it. That allows one to predict within statistical confidence levels, say 95%, the number of years within which humans will disappear. Estimates of past and future population vary, of course, but the primary point of the argument is that the human species may become extinct within several thousand years. Following is Nick’s analysis. “Rarely does philosophy produce empirical predictions. The Doomsday argument is an important exception. From seemingly trivial premises it seeks to show that the risk that humankind will go extinct soon has been systematically underestimated. Nearly everybody's first reaction is that there must be something wrong with such an argument. Yet despite being subjected to intense scrutiny by a growing number of philosophers, no simple flaw in the argument has been identified. It started some fifteen years ago when astrophysicist Brandon Carter discovered a previously unnoticed consequence of a version of the weak anthropic principle. Carter didn't publish his finding, but the idea was taken up by philosopher John Leslie who has been a prolific author on the subject, culminating in his monograph The End of the World (Routledge, 1996). Versions of the Doomsday argument have also been independently discovered by other authors. In recent years, there have been numerous papers trying to refute the argument, and an approximately equal number of papers refuting these refutations…. After hearing about it, many people think they know what is wrong with it. But these objections tend to be mutually incompatible, and often they hinge on some simple misunderstanding. Be sure to read the literature before feeling too confident that you have a refutation. If the Doomsday argument is correct, what precisely does it show? It doesn’t show that there is no point trying to reduce threats to human survival ‘because we’re doomed anyway’. On the contrary, the Doomsday argument could make such efforts seem even more urgent. Working to reduce the risk that nanotechnology will be abused to destroy intelligent life, for example, would decrease the prior probability of Doom Soon, and this would reduce its posterior probability after taking the Doomsday argument into account; humankind’s life expectancy would go up. So although the Doomsday argument contains an interesting idea, it needs to be combined with additional assumptions and principles (some of which remain to be worked out) before it can be applied to the real world. In all likelihood, even when all details are filled in, there will be scope for differing opinions about our future. Nonetheless, a better understanding of observational selection effects will rule out certain kinds of hypotheses and impose surprising constraints on any coherent theorizing about the future of our species and about the distribution of observers in the universe.”