Hume proposes the idea that moral principles are rooted in their utility, or usefulness, rather than in God’s will. His version of this theory is unique. Unlike his Utilitarian successors, such as John Stuart Mill, Hume did not think that moral truths could be arrived at scientifically, as if we could add together units of utility and compare the relative utility of various actions. Instead, Hume was a moral sentimentalist who believed that moral principles cannot be intellectually justified as scientific solutions to social problems.
Hume argues that some principles simply appeal to us and others do not. Moral principles appeal to us because they promote our interests and those of our fellow human beings, with whom we naturally sympathize. In other words, humans are biologically inclined to approve and support whatever helps society, since we all live in a community and stand to benefit. Hume used this simple but controversial insight to explain how we evaluate a wide array of phenomena, from social institutions and government policies to character traits and individual behavior.