In this paper, I address the Special Omission Question (SOQ): under what conditions does a disjunction count as an omission? If omissions are events essentially specified as non-occurrences, then their conditions of occurrence can be formulated as disjunctions of overly varied disjuncts. This suggests that omissions are disjunctive events. For example, one might say that the universe omits to contain events that violate the laws of nature (see Lewis 1986a: 190). I suggest that this kind of case still counts as an omission, and I further discuss some additional difficult cases that have largely been ignored in the literature. I consider three possible answers to the SOQ: always, never, and sometimes. Rather than decisively rejecting the first two options, I develop the ‘sometimes’ view: some disjunctions count as omissions, while others do not. This view provides a way to distinguish genuine omissions from arbitrary disjunctions. Compared with my theory, I suggest that Silver’s (2018) theory is not adequate to account for omissions.
