Abstract
I present and develop the view that omissions are de re possibilities of actual events. Omissions do not literally fail to occur; rather, they possibly occur. An omission is a tripartite metaphysical entity composed of an actual event, a possible event, and a contextually specified counterpart relation between them. This view resolves ontological, causal, and semantic puzzles about omissions, and also accounts for important data about moral responsibility for outcomes resulting from omissions