We claim that impersonal passive constructions are a type of existential that assert the novel existence (or occurrence) of an event. We claim that the well-known restriction against telic predicates in impersonal passive constructions follows naturally from this characterization. Telic predicates are made up of two events; a process and an endpoint. We show, using standard tests for presuppositionality, that presupposition of the process component of the bipartite event structure in telics is forced by the assertion of the endpoint component. Presupposed elements are not pragmatically consistent with existentials, hence telic predicates are ruled out in these constructions. The approach presented here is contrasted with other analyses in the literature, particularly that of Goldberg 1995.