Does longtermism depend on questionable forms of aggregation?

Abstract

We are constantly making choices about how to invest our time and resources. From a moral perspective, we must ask which moral concerns are most deserving of our attention. Longtermism, as e.g. defined by Greaves and MacAskill, holds that our moral focus should be on the long-term future, and that current and medium-term moral problems are comparatively insignificant. This theory is centrally based on the assumption that the moral importance of individuals can be aggregated. Since the number of individuals of future generations far exceeds the number of current individuals and those closer in time, future generations are to be morally prioritised, according to longtermism. This paper explores the implications of rejecting the premise of moral aggregation of individuals and adopting a strongly non-aggregationist position instead. It is argued that, according to strong non-aggregationism, the magnitude of the probability with which our intervention actually make a difference, as well as whether we look at the available interventions from an ex ante or ex post perspective, are relevant factors in their moral assessment. Ultimately, the conclusion is reached that strong non-aggregationism does likely not support strongly longtermist conclusions.