Contemporary theological and philosophical ethicists posit the ability of human beings to achieve solidarity with one another on a large social scale. However, many people, including politicians and key decision-makers, have argued that this kind of solidarity is not possible. Several current anthropological theories, such as those undergirding neoclassical economic theory and the realist school of international relations, maintain that individuals and nations essentially act in their own interest. “Selfish” human nature discounts the possibility of broad and sustained solidarity. This paper addresses the question of whether or not human nature contains the potential and impulse to practice solidarity to ever greater degrees. First, it brie...