Population ethics
[3] While scholars have proposed and debated many different population ethical theories, no consensus in the academic community has emerged.
[4] Hilary Greaves, Oxford Professor of Philosophy and director of the Global Priorities Institute, explains that this is no coincidence, as academics have proved a series of impossibility theorems for the field in recent decades.
In his Reasons and Persons, Derek Parfit was among the first to spell out and popularize this implication in the academic literature, coining it the "repugnant conclusion".
[6] Greaves writes that Parfit searched for a way to avoid the repugnant conclusion, but that he failed to find any alternative axiology that he himself considered satisfactory, but [Parfit] held out hope that this was merely for want of searching hard enough: That, in the future, some fully satisfactory population axiology, called "Theory X" by way of placeholder, might be found.
In light of this, several prominent academics have come to accept and even defend the repugnant conclusion, including philosophers Torbjörn Tannsjö[7] and Michael Huemer,[8] because this strategy avoids all the impossibility theorems.
[11] Taken together, these claims entail what Greaves describes as the neutrality principle: "Adding an extra person to the world, if it is done in such a way as to leave the well-being levels of others unaffected, does not make a state of affairs either better or worse.
"[1] However, person-affecting views generate many counterintuitive implications, leading Greaves to comment that "it turns out to be remarkably difficult to formulate any remotely acceptable axiology that captures this idea of neutrality".
[20][21] Population ethical problems are particularly likely to arise when making large-scale policy-decisions, but they can also affect how we should evaluate certain choices made by individuals.
Examples of practical questions that give rise to population ethical problems include the decision whether or not to have an additional child; how to allocate life-saving resources between young and old people; how many resources to dedicate to climate change mitigation; and whether or not to support family planning programs in the developing world.
[23] On this basis, Oxford philosopher Nick Bostrom argues that the prevention of existential risks to humanity is an important global priority in order to preserve the value of the many lives that could come to exist in the future.
[25][26][27] Longtermist ideas have been taken up and are put into practice by several organizations associated with the effective altruism community, such as the Open Philanthropy Project and 80,000 Hours, as well as by philanthropists like Dustin Moskovitz.
