An apparently quite specific question that was addressed by both Confucius and Socrates has attracted much attention in Sino-Hellenistic comparative philosophy. Their respective responses to the question of how a son should respond if his father commits a crime are found in Confucius' Analects 13:18 and in Plato's Euthyphro. This essay assesses three comparative analyses of these responses with particular reference to their underlying assertions of commonality, that is, the assumptions or presuppositions of commonality that serve to justify the comparative exercise in the first instance. The authors suggest that two of the analyses assert commonality between their two responses from a Confucian standpoint, while the third constructs commonality from a Socratic standpoint. The authors argue that the response of Confucius focuses specifically on the issue of xiao (filial piety) in the concrete situation presented to him, whereas Socrates uses the issue to investigate the different question known as the "Euthyphro dilemma." Some brief conclusions are drawn regarding comparative philosophical analysis in general and about comparing the responses of Confucius and Socrates in these passages in particular.