[sandgiant]

There are no such things as absolute static things in relativity theory. "Before" and "After" depend entirely on the observer. Energy/matter and spacetime are deeply connected through the Einstein equations, so much so that they may indeed be "the same underlying thing".

Approximate static time and space are convenient illusions/approximations, that happen to be very useful for us as a species when it comes to surviving and replicating, but the Universe has no obligation to cater to our feeble minds or senses when it comes to reality.

[tsimionescu]

> "Before" and "After" depend entirely on the observer.

This is only true for space-like separated events. But the earth gets wet After the rain started, for any observer in any frame of reference whatsoever. The eggs have to break Before you can make the omelette.

[raattgift]

Lorentzian manifolds come with a definition of causality. The spacetime of Special Relativity is a Lorentzian manifold. An additional condition of time-orientability obliterates the free choice of an observer on a "comes-before"/"comes-after" relation between observable events.

A further condition of global hyperbolicity also determines the "comes-before"/"comes-after" relation between unobservable events. This condition can be fixed by (i) a non-Minkowski metric, or (ii) by constraints on the pattern of events in the gravitation-free metric of Special Relativity (an example of such constraints is thermodynamics). Sloganizing this: "states of matter tells you what configuration came before/came after" in the second case, and also in the first case if the non-Minkowski metric's source is only matter; otherwise you need to do a causality analysis, e.g. by fixing causal cones on curves (paths, trajectories - they don't have to be geodesics) of interest or solving the relevant wave equations).

https://en.wikipedia.org/wiki/Causal_structure

https://en.wikipedia.org/wiki/Causality_conditions

As a practical matter, the initial value formulation of General Relativity <https://en.wikipedia.org/wiki/Initial_value_formulation_(gen...> (and numerical relativity built on that) is popular and of practical use because so far there is no reason to describe a natural system (where gravity isn't just ignored) in a way that breaks global hyperbolicity.

[psychoslave]

>There are no such things as absolute static things in relativity theory.

Well there is light-speed, which is an "absolute universal constant" - though of course light-speed is directly related to time. Also general relativity as a bit more to say on the topic.

>Approximate static time and space are convenient illusions/approximations, that happen to be very useful for us as a species when it comes to surviving and replicating, but the Universe has no obligation to cater to our feeble minds or senses when it comes to reality.

Sure. Even theories that don’t rely on time to be a fundamental dimension fall in the same category of "universe doesn’t need our small minds to be able to grab its actual complexity".