> Are you a physicist? Not trying to be snarky.
Yes, I've studied and done physics research (I have yet to finish my degree, but I've completed all of the physics topics). (My research topics were on astroseismology and non-linear optics -- not related to SR or GR, but we went through the derivations and reasoning of SR in class.)
> I think GR is at Newton's level.
I think you've misunderstood what I meant by "people over-complicate Einstein's work". My point wasn't that Einstein is somehow inferior to Newton, it was that a large part of Einstein's work is actually incredibly simple (compared to how it is pitched) which to me makes it all the more genius.
> GR came out of the blue, it wasn't strictly required to explain anything important back then.
The core idea behind GR came from thought experiments trying to understand how SR might be extended to non-inertial frames. In many ways this is the most obvious thing to consider after you've come up with SR: "what if we start accelerating?"
Also, SR similarly wasn't required to explain anything important. Einstein was thinking very deeply about what does it mean to "measure" something, and the first section of his paper was discussions of synchronized clocks and how they relate to measurements (possibly the furthest thing from a "real" problem you can have).
> then a huge, incomprehensible (to me) mental leap to manifolds and tensors, and the Einstein equation.
In Einstein's case, he had quite a bit of help with the mathematics (again, not to detract at all -- but we should separate the mathematical derivation from intuition). Intuition is the driving force in physics (with mathematics fleshing out what the logical conclusion of an intuition must be), and so I find discussing the intuition to be far more critical when talking about physical theories.
The core genius was the realisation that acceleration changes how light beams look to observers -- and the intuition that acceleration must have an equivalence to gravity. Neither of these things are complicated, and you could explain them to anyone who has seen a projectile or stood in an elevator. But the conclusion you come to is far from obvious.
And that, to me, is the beauty of physics. Obviously the intuition is just the first step, and there is plenty of brilliance in all of the manifold and tensor equations (it's definitely above my pay-grade), but I think that over-hyping the mathematics isn't quite right either.
> It's hard to compare it to Newton, bc Newton also had to invent Calculus, but it's up there.
That is effectively what I was saying. Newton had Principa Mathematica and in many ways pioneered the mathematical viewpoint that we use in physics today.
