The dysgenics objection to longtermism

Strong longtermism maintains that how we should act morally is determined almost entirely by the expected effects on the welfare of our descendants existing thousands if not millions of years into the future, who might include both other humans and any artificial agents with a comparable or higher moral status that we end up creating. It is based on three key assumptions: (i) that our descendants will have a moral status that is at least as high as ours and therefore should not have their welfare discounted by us; (ii) that there is a good chance that these individuals will vastly outnumber us; and (iii) that we can do things here and now that can be expected to positively shape the long-term trajectory of humanity. The aim of this contribution is to suggest that authors such as Will MacAskill and Hilary Greaves have been too optimistic about all these assumptions as a result of having ignored evidence that the populations of post-industrial countries are becoming less intelligent due mostly to the negative relationship that has emerged within these societies between intelligence and fertility and to the proclivity of intelligent people to delay parenthood.