Within the realm of management and the other social sciences, many scholars have used self-interest explanations to account for individual judgment, decision making, and behavior with respect to a variety of issues in the domains of ethics and justice. In this article, the authors address the descriptive claim that all human behavior can ultimately be traced to underlying self-interest. Reviewing arguments from the philosophical literatures and evidence from management, social psychology, and behavioral economics, the authors argue that exclusively relying on self-interest explanations is a bad scientific strategy that discourages researchers from considering other determinants of how people behave.