I argue that theoretical developments in the study of the Universal Declaration of Human Rights (UDHR) should occur alongside progress in moral psychology, particularly moral cognition. More specifically, I argue that Universal Moral Grammar (UMG), a model positing an innate, regulative, and universal moral faculty characterizable in terms of rules and principles, fulfills the role of the foundational model needed to usefully conceptualize the UDHR. As such, I provide a detailed account of UMG against competing models in moral psychology. Furthermore, (...) I combine UMG with Talbott’s Historical-Social Process of Moral Discovery and Rawls’s reflective equilibrium to show how the UDHR represents a major development in moral exploration, one indicating a more penetrative look into the inner moral nature of humans that attempts to reach, but does not attain, one interpretation of reflective equilibrium tied to cognitive moral psychology. (shrink)