In a recently published article, I have reported on an axiomatization of the relativistic space-time theory. In light of this, we may now test the possibility of absolute time by investigating which axioms are and are not compatible with it.

One possibility for defining the synchronization of clocks, so that the same simultaneity relation holds for all systems, arises from the transportation of clocks. Two clocks that are brought into synchronization at the same place are to be called synchronized as well when one or the other is transported to a different place. This is a definition of simultaneity and is neither true nor false, but an arbitrary rule. For that reason it can be used in any case; but in order to be univocal, it must satisfy the following axiom:

Axiom A

Two clocks that are synchronized at one place are always synchronized when compared at the same place regardless of the paths of transport.

By “clock” we understand here a closed periodic system. is satisfied is a mere matter of fact and can be decided independently of the definition of simultaneity for distant places and independently of the theory of relativity. The theory maintains ‘and it has received extremely indirect confirmation’ that axiom A is false, and therefore it rejects absolute time; but to the present, no means had been found to directly test the axiom.