According to the Ontological Innocence Thesis (OIT), grounded entities are ontologically innocent relative to their full grounds. I argue that OIT entails a contradiction, and therefore must be discarded. My argument turns on the notion of “groundmates,” two or more numerically distinct entities that share at least one of their full grounds. I argue that, if OIT is true, then it is both the case that there are groundmates and that there are no groundmates. Therefore, so I conclude, OIT is false. Moreover, once we have seen why OIT is false, only three heterodox views about reality's structure remain. So this paper’s second conclusion is that, even after we have discarded OIT, we are in for an additional surprise
