Which attitudes, mindsets, and personal qualities do scholars deem crucial for inter- and transdisciplinary (ITD) research? And how has this changed over time? In this article, we answer these questions by looking at foundational texts on inter- and transdisciplinarity published between the 1970s and the early 2000s. We show that virtues such as reflexivity, responsibility, and creativity were prominent in both early and more recent ITD literature. Although additional virtues--including open-mindedness, flexibility and being a good teamworker--came into focus later, the virtues that were considered important seem surprisingly stable over time. This saturation of the discourses on virtues was indicative of ITD studies becoming an established research field in its own right. However, the basis for these claims has changed between the periods studied. Over time, the texts became less prescriptive and argumentative, and became more descriptive, relying on literature reviews and empirical studies to support claims about required qualities of ITD scholars. This shift in the way ITD and its virtues are being talked about is consistent with studies of ITD entering a stage of consolidation as a distinct research field. We argue that this also puts the field at risk of developing blind spots for collective assumptions. We therefore take our findings as a call for the continued critical examination of ITD virtues, both from within and outside the field of ITD studies. Finally, as a step forward we suggest in-depth ethnographic studies to gain insights into ITD practices grounded in theory and philosophical argumentation, and move beyond self-report based research that may feed reproduction. [Note: The page range (249-268) shown in the citation is incorrect. The correct page range is 249-267.]