Balashov on special relativity, coexistence, and temporal parts

Yuri Balashov has argued that endurantism is untenable in the context of Minkowski spacetime. Balashov's argument runs through two main these concerning the relation of coexistence, or temporal co-location. (1) Coexistence must turn out to be an absolute or objective matter; and in Minkowski spacetime coexistence must be grounded in the relation of spacelike separation. (2) If endurantism is true, then (1) leads to absurd conclusions; but it perdurantism is true, then (1) is harmless. I object to both these. Against (1), I argue that coexistence is better construed as being relative to a hyperplane of simultaneity. Against (2), I argue that the consequences of (1) given endurantism are no worse than the consequences of (1) given perdurantism.