Freixas said:
My point about geometry and coordinate systems is that they assume a God-like view.
In a hypothetical scenario, yes, that's true. But that's precisely because the scenario is
hypothetical. In a hypothetical scenario, the person making up the scenario can simply dictate by fiat what happens. That includes dictating by fiat what happens in the causal future of any event of interest. So the person making up the scenario
does have a "God-like view" of what happens
in the scenario.
In the real world, however, nobody has such a view; yet we routinely assign coordinates to hypothetical events in our causal future. For example, when the Apollo program sent astronauts to the Moon, the engineers calculated coordinates at which the spacecraft would be at future times. That doesn't mean they were assuming a "God-like view" where they knew for certain what would happen in the future--the most obvious counterexample to that claim is Apollo 13, in which the spacecraft ended up following a very different trajectory from the one that was calculated before launch. But the fact that calculations of what is expected to happen in the future are never certain does not make them useless; far from it. Apollo 13 would never have made it back to Earth if the engineers at NASA had not been able to quickly make
new calculations once they knew there was a problem aboard the spacecraft .
In other words, calculations about hypothetical future events are
predictions. They are constructions of a model that extends what is currently known based on the laws of physics and particular assumptions about the specific situation--for example, the assumption that the Apollo third stage is going to fire at a particular time at a particular point in low Earth orbit to boost the spacecraft towards an expected arrival at a particular point in the Moon's orbit at a particular time. And that constructed model gets built the same way all models in physics, or at least all models that are going to be used for numerical calculations, get built--using coordinates and spacetime geometry. (Strictly speaking, the Apollo calculations were non-relativistic, but that doesn't change the fundamental point.)
In short, building a model using coordinates and spacetime geometry that extends what is currently known based on certain assumptions is
not the same as claiming that every single event in that model, including ones in the causal future of the event where the model is built, is fixed and certain.