Abstract

Populations, species, biotic communities, ecosystems, landscapes, biomes, and the biosphere are the referents of “ecological collectives.” The essence-accident moral ontology prevailing in twentieth-century moral philosophy cannot, while the theory of moral sentiments originating with Hume, biologized by Darwin, and ecologized by Leopold can, endow ecological collectives with moral considerability. The Hume-Darwin-Leopold approach to environmental ethics has been validated by twenty-first-century evolutionary moral psychology, while the twenty-first-century analysis of the human microbiome has revealed that erstwhile human “individuals” are themselves ecological collectives, thus rendering future ethical theory exclusively concerned with ecological collectives. To reconceptualize ourselves as moral beings in relational, communal, and collective terms is a matter of the greatest urgency for twenty-first century moral philosophy.