The following argument is valid:
- (Premise) If there are no haecceities, then there are no propositions de re about non-existent individuals.
- (Premise) If presentism is true, then Seabiscuit is a non-existent individual.
- (Premise) That Seabiscuit was essentially a horse is a proposition de re about Seabiscuit.
- Therefore, if presentism is true, there are haecceities.
However, I think (1) is false, because I think contingent entities are wholly individuated by the histories of their origins, where their histories are described in wholly general terms (i.e., without de re reference to any individuals). Consequently, if H is such a history of Seabiscuit, the proposition in (3) can be expressed: "Necessarily, if H is instantiated, it is instantiated by a horse."