How many lives does the future hold?

Toby Newberry (Future of Humanity Institute, University of Oxford)

GPI Technical Report No. T2-2021

The total number of people who have ever lived, across the entire human past, has been estimated at around 100 billion.2 The total number of people who will ever live, across the entire human future, is unknown - but not immune to the tools of rational inquiry. This report estimates the expected size of the future, as measured in units of ‘human-life-equivalents’ (henceforth: ‘lives’). The task is a daunting one, and the aim here is not to be the final word on this subject. Instead, this report aspires to two more modest aims...

Other working papers

The long-run relationship between per capita incomes and population size – Maya Eden (University of Zurich) and Kevin Kuruc (Population Wellbeing Initiative, University of Texas at Austin)

The relationship between the human population size and per capita incomes has long been debated. Two competing forces feature prominently in these discussions. On the one hand, a larger population means that limited natural resources must be shared among more people. On the other hand, more people means more innovation and faster technological progress, other things equal. We study a model that features both of these channels. A calibration suggests that, in the long run, (marginal) increases in population would…

Moral demands and the far future – Andreas Mogensen (Global Priorities Institute, Oxford University)

I argue that moral philosophers have either misunderstood the problem of moral demandingness or at least failed to recognize important dimensions of the problem that undermine many standard assumptions. It has been assumed that utilitarianism concretely directs us to maximize welfare within a generation by transferring resources to people currently living in extreme poverty. In fact, utilitarianism seems to imply that any obligation to help people who are currently badly off is trumped by obligations to undertake actions targeted at improving the value…

Three mistakes in the moral mathematics of existential risk – David Thorstad (Global Priorities Institute, University of Oxford)

Longtermists have recently argued that it is overwhelmingly important to do what we can to mitigate existential risks to humanity. I consider three mistakes that are often made in calculating the value of existential risk mitigation: focusing on cumulative risk rather than period risk; ignoring background risk; and neglecting population dynamics. I show how correcting these mistakes pushes the value of existential risk mitigation substantially below leading estimates, potentially low enough to…