contradictory, and he believes that one's moral life should be coherent and self-consistent; however, he also believes that each person should be free to adopt the theory that to them is the most intellectually compelling (interpersonal pluralism). The general theory that Callicott espouses, Humean communitarianism, correlates ethics to community membership. And because each moral agent is subject to as many ethics as his or her community memberships, therefore each person is subject to a plurality of duties and obligations (normative pluralism). In sum, Callicott is a theoretical monist and an interpersonal and normative pluralist. Callicott's comparative environmental philosophy also involves a tightrope walk between pluralism and monism. In Earth’s Insights: A Multicultural Survey of Ecological Ethics from the Mediterranean Basin to the Australian Outback, he seems to embrace pluralism by exploring the conceptual resources for environmental ethics in a wide variety of religious and indigenous worldviews. This work has been criticized, however, for privileging the Leopold land ethic as a norm in reference to which such alternative environmental ethics are evaluated. As Andrew Light observes, Callicott does not insist that the Leopold land ethic is based on the uniquely true worldview of evolutionary biology and ecology. He agrees with multicultural pluralists that the evolutionary-ecological worldview is but one story among many stories. But he does argue that the worldview of evolutionary biology and ecology is more tenable than any other, that the evolutionary-ecological epic is a better story than any other grand narrative. Callicott's justification for this claim is an analysis based on the following criteria for tenability: self-consistency; comprehensiveness; self-correction; universality; and beauty. The first test of a scientific worldview is logical self-consistency and the evolutionary-ecological worldview passes that test. A tenable scientific worldview must comprehend all known facts and so far the evolutionary-ecological worldview does account for all the facts, such as the existence of the fossil remains of extinct species. When the details of that worldview are shown to be inconsistent with themselves or unable to account for all the facts, the theory is revised accordingly; the evolutionary-ecological worldview is thus self-correcting and is therefore, Callicott believes, becoming ever more refined. The evolutionary-ecological worldview has global currency and enjoys international credibility; that is, it has universal appeal. And finally, as to beauty, Darwin himself observed in the final sentence of the Origin that “There is grandeur in this view of life, with its several powers, having been