We examine non-commitment in the imagination. Across 5 studies (N > 1, 800), we find that most people are non-committal about basic aspects of their mental images, including features that would be readily apparent in real images. While previous work on the imagination has discussed the possibility of non-commitment, this paper is the first, to our knowledge, to examine this systematically and empirically. We find that people do not commit to basic properties of specified mental scenes (Studies 1 and 2), and that people report non-commitment rather than uncertainty or forgetfulness (Study 3). Such non-commitment is present even for people with generally vivid imaginations, and those who report imagining the specified scene very vividly (Studies 4a, 4b). People readily confabulate properties of their mental images when non-commitment is not offered as an explicit option (Study 5). Taken together, these results establish non-commitment as a pervasive component of mental imagery.