Population ethics is the philosophical study of the ethical problems arising when our actions affect who is born and how many people are born in the future. An important area within population ethics is population axiology, which is "the study of the conditions under which one state of affairs is better than another, when the states of affairs in question may differ over the numbers and the identities of the persons who ever live."[1]
Moral philosopher Derek Parfit brought population ethics to the attention of the academic community as a modern branch of moral philosophy in his seminal work Reasons and Persons in 1984.[2] Discussions of population ethics are thus a relatively recent development in the history of philosophy. Formulating a satisfactory theory of population ethics is regarded as "notoriously difficult".[3] While scholars have proposed and debated many different population ethical theories, no consensus in the academic community has emerged.
Gustaf Arrhenius, Professor of Philosophy and Director of the Institute for Futures Studies, comments on the history and challenges within population ethics that
For the last thirty years or so, there has been a search underway for a theory that can accommodate our intuitions in regard to moral duties to future generations. The object of this search has proved surprisingly elusive. ... The main problem has been to find an adequate population theory, that is, a theory about the moral value of states of affairs where the number of people, the quality of their lives, and their identities may vary. Since, arguably, any reasonable moral theory has to take these aspects of possible states of affairs into account when determining the normative status of actions, the study of population theory is of general import for moral theory.[4]