Abstract
Many philosophers have become familiar with Leopold’s land ethic through the writings of J. Baird Callicott, who claims that Leopold bases his land ethic on a ‘protosociobiological’ argument that Darwin gives in the Descent of Man. On this view, which has become the canonical interpretation, Leopold’s land ethic is based on extending our moral sentiments to ecosystems. I argue that the evidence weighs in favor of an alternative interpretation of Leopold; his reference to Darwin does not refer to the Descent, but rather to the Origin of Species, where Darwin discusses the interdependencies between organisms in the struggle for existence.