Given a fixed maximum speed of action, the speed of light, events in spacetime can be ordered via metric = x^2 + y^2 + z^2 - ct^2 But yes, you are sort of corr

Given a fixed maximum speed of action, the speed of light, events in spacetime can be ordered via metric = x^2 + y^2 + z^2 - ct^2 But yes, you are sort of correct, two events can have the same metric, and one would not be able to distinguish which of them is responsible, if they are both capable of becoming present at the same speed.