crowman

Thanks Genady, I think that’s makes it a bit more clearer for me. IOW, It’s not a leap-frog situation with one part then the other part and so on. Thank you Markus. So, that would be like ending up with the spacetime geometry around a central symmetrical mass (sphere) Schwarzschild model.

Would a roundabout way of saying that be, there is no absolute spacetime and so no frame is special? Hence, no background dependency when it comes to spacetime. That’s how I’m making sense of it. Something to do with the field equations being in two parts, the movements of mass / energy dictates the spacetime geometry and vice versa?

Yes, you're right, thanks. On Earth, a thrown stone will naturally take a path that results in maximum ageing between launch and impact. The stone didn't read a clock or use a ruler. I only say this because your "gravity affects all rulers and clocks" leaves the backdoor open to calls of "it only affects the instruments of measurement."

Would it be fair to say that 'reality' certainly acts like space-time is a non-euclidean curved manifold, and that physics can't show that it's not? I don't know if that's a catch 22 or not?

Howdy all.