Abstract
Environmental ethics consists of a set of competing theories about whether human actions and attitudes to nature are morally right or wrong. Ecocentrists are holists whose theory locates the primary site of value in biological communities or ecosystems and who tend to regard actions interfering with the progress of an ecosystem toward its mature equilibrium state as prima facie wrong. I suggest that this form of ecocentrism may be built on a questionable scientific foundation, organismic ecology, and that a better scientific foundation for environmental ethics may be found in individualistic neo-Darwinian population biology. However, the latter approach probably requires a corresponding shift away from ethical holism and toward approaches locating value primarily in individuals. I call such environmental ethicists ‘extensionists’ and briefly outline an extensionist environmental ethic.