Jean Piaget’s research program—which involved the study of child development as a central feature (viz. "stages"), but which can be understood more broadly as advancing a constructive theory of knowledge (i.e., "genetic epistemology")—is thought by many contemporary developmentalists to have been guided by a coherent, complete, and unchanging meta-theoretical framework: "equilibration." While this is correct philosophically, it is incorrect historically. Briefly put: the formal meaning of equilibration changed over time, and thus so too did the entirety of the theory that relied upon it. To focus in on one specific change of particular importance, this article examines how Piaget appealed to the changing ideas of Kurt Gödel and their interpretations by French-speaking logicians. This historical analysis (a Foucauldian archaeology) thereby excavates a "neo-Gödelian turn" in Piaget’s research program. The resulting framework is then sketched in outline: the updated formal meta-theory that made possible "Piaget’s new theory."