This paper argues that Mencius is a eudaimonist, and that his eudaimonism plays an architectonic role in his thought. Mencius maintains that the most satisfying life for a human being is the life of benevolence, rightness, wisdom, and ritual propriety, and that such a life fulfills essential desires and capacities of the human heart. He also repeatedly appeals both to these and to morally neutral desires in his efforts to persuade others to develop and exercise the virtues. Classical Greek eudaimonists (...) similarly regarded the life of virtue as both objectively good and subjectively desirable, and appealed to the desire for eudaimonia or happiness to motivate a commitment to the virtues. Mencius offers a carefully crafted, teleological account of human nature that appears designed in part to support his eudaimonism. In contrast with proposals by other scholars, I argue that Mencius’ notion of happiness, analogous to the Greek eudaimonia, is expressed by the construction jìn xìng 盡性, “fulfilling human nature” or the nearly equivalent jìn xīn 盡心, “fulfilling one’s heart.”. (shrink)