Alongside today’s respect for human life there is the increasingly popular idea that there is too much human life around, and that it is killing the planet. Since the beginning of time, one of the clearest markers of an enlightened society has been the moral status it attaches to human life. And outwardly, at least, twenty-first-century Western societies express an unprecedented degree of respect for human life. For example, cultural and political institutions continually talk about the need to uphold human rights. The human rights narrative now shapes policymaking, both domestically and internationally. Many even argue that protecting human rights...