Our analysis revealed that MNI researchers were generally favorable toward the notion of open science, reporting that they already engage in significant sharing. Nevertheless, almost half our interviewees noted that the concept is vague (Fecher and Friesike, 2014; Grubb and Easterbrook, 2011; OECD, 2015) and expressed uncertainty about what precisely open science would require of them (Open Research Data Task Force, 2017; Neylon, 2017; Ferguson, 2014). Based on our data, this uncertainty can discourage participation in two ways. First, the absence of clearly articulated definitions raised fears that open science practice may extend beyond comfort levels. Conversely, those who desired greater openness were cautious about taking part lest the lack of clarity prevent meaningful change.