Tiny probabilities and the value of the far future

Petra Kosonen (Population Wellbeing Initiative, University of Texas at Austin)

GPI Working Paper No. 1-2023

Morally speaking, what matters the most is the far future - at least according to Longtermism. The reason why the far future is of utmost importance is that our acts' expected influence on the value of the world is mainly determined by their consequences in the far future. The case for Longtermism is straightforward: Given the enormous number of people who might exist in the far future, even a tiny probability of affecting how the far future goes outweighs the importance of our acts' consequences in the near term. However, there seems to be something wrong with a theory that lets very small probabilities of huge payoffs dictate one's own course of action. If, instead, we discount very small probabilities to zero, we may have a response to Longtermism provided that its truth depends on tiny probabilities of vast value. Contrary to this, I will argue that discounting small probabilities does not undermine Longtermism.

Other working papers

Should longtermists recommend hastening extinction rather than delaying it? – Richard Pettigrew (University of Bristol)

Longtermism is the view that the most urgent global priorities, and those to which we should devote the largest portion of our current resources, are those that focus on ensuring a long future for humanity, and perhaps sentient or intelligent life more generally, and improving the quality of those lives in that long future. The central argument for this conclusion is that, given a fixed amount of are source that we are able to devote to global priorities, the longtermist’s favoured interventions have…

The Conservation Multiplier – Bård Harstad (University of Oslo)

Every government that controls an exhaustible resource must decide whether to exploit it or to conserve and thereby let the subsequent government decide whether to exploit or conserve. This paper develops a positive theory of this situation and shows when a small change in parameter values has a multiplier effect on exploitation. The multiplier strengthens the influence of a lobby paying for exploitation, and of a donor compensating for conservation. …

Welfare and felt duration – Andreas Mogensen (Global Priorities Institute, University of Oxford)

How should we understand the duration of a pleasant or unpleasant sensation, insofar as its duration modulates how good or bad the experience is overall? Given that we seem able to distinguish between subjective and objective duration and that how well or badly someone’s life goes is naturally thought of as something to be assessed from her own perspective, it seems intuitive that it is subjective duration that modulates how good or bad an experience is from the perspective of an individual’s welfare. …