Causality and Temporal Order in Special Relativity

David Malament tried to show that the causal theory of time leads to a unique determination of simultaneity relative to an inertial observer, namely standard simultaneity. I show that the causal relation Malament uses in his proofs, causal connectibility, should be replaced by a different causal relation, the one used by Reichenbach in his formulation of the theory. I also explain why Malament’s reliance on the assumption that the observer has an eternal inertial history modifies our conception of simultaneity, and I therefore eliminate it. Having made these changes, Malament’s uniqueness result no longer follows, although the conventionality of simultaneity is not reinstated. I contrast my approach with previous criticisms of Malament.