Local and regional environments have for many centuries been seen as, or as being composed of, ''natural resources,'' which have generally been considered fully available for human use, irrespective of any use to which other species, purposefully or not, might put them. The global environment has more recently, though less routinely, been seen in this way. I examine full-human-use arguments in three widely credited philosophical traditions: the Judeo-Christian-liberal, the Aristotelian-Cartesian-rationalist, and the utilitarian or neoclassical economic. I find each tradition's full-human-use argument unsatisfactory. I then discuss, and ultimately recommend, an alternative, an all-species-use argument based on Albert Schweitzer's much admired but seldom adopted reverence-for-life ethic. I find revealed by this alternative argument a previously unnamed good, one worthy of honor, protection, and enlargement; I call this good ''the commonwealth of life.'' In conclusion, I consider important implications of accepting commonwealth-of-life reasoning, including foundational changes in ethics.