There's a website called Arcane Knowledge written by a Catholic named Daniel J. Castellano that includes several articles on Special Relativity that try to argue that the theory doesn't entail eternalism (the view that all moments of time have equal existence). Now if you've read my blog at any length, you know I'm a big proponent of the view that Special Relativity does necessitate eternalism. So naturally, I disagree with much of what is written on the site.
Many of the theists I've debating eternalism with have cited this website and its arguments against the reality of a 4 dimensional spacetime block universe. (Not surprisingly, they've all been Catholics subscribing to Aristotelian-Thomistic metaphysics).
Through a year long debate with a Catholic who frequently cited Arcane Knowledge in an attempt to deny Special Relativity entails eternalism, I've constructed an argument below showing how the arguments used on Arcane Knowledge to deny eternalism forces one into a dilemma: either (a) affirm you are the only thing that exists at any given present moment for you (literally deny the existence of everything else), or (b) be forced to agree events in the past and future exist (effectively affirming eternalism).
Over on the site, Daniel argues that from any event considered present, no events in the absolute future or past will have any objective ontological status, but any events in "elsewhere" could physically exist. In Special Relativity, "elsewhere" is a term given to all the places not in an event's absolute future or past (which are its future and past light cones, respectively). In other words, elsewhere is the totality of spacelike separated events. According to Daniel, one cannot say whether any events in elsewhere exist when one is at the present moment, seen below in the spacetime diagram as a green dot (the coordinates of this dot at (0,0) on the X and Y axis). It is physically possible, according to this view, that any set of events can possibly exist in elsewhere.
This interpretation of Special Relativity is problematic in several ways, and I will show how. If an event's absolute future and past objectively doesn't exist, this would have to apply to all other events that exist, since there's nothing special about any given event we make the center of a spacetime diagram. Given this rule, no other events can exist in elsewhere that are in the absolute futures or pasts of any other events in elsewhere. For example, in the diagram below, it is possible events A and B can exist, since they're not in each other's absolute future or past.
But in this diagram below, it cannot be the case that both events A and B exist, since event A is in the absolute past of event B, and event B is in the absolute future of event A.
A quick side note of what is meant by the absolute future and past: The absolute future and past of an event are all the areas relative to that event's location where all inertial frames would agree are objectively in the future or in the past if they were all in that event's location, even if they're moving relative to each other. They are the future and past light cones.