>"How can you claim this? GR is derived from first principles only. It also does not need any new physical constant to describe Mercury's apsidal precession."

>"How can you claim this? GR is derived from first principles only. It also does not need any new physical constant to describe Mercury's apsidal precession." You can derive many theories from first principles but they need to be checked against observation to be useful physics... explaining the orbit of mercury was one of the main checks of any theory. All theories that could not explain that better than Newton were filtered out. My point is only this does not count as a prediction, which needs to be on new data. >"What?! How can you possibly claim that work published in the 1930s predates GR" This is something you've made up? The source I provided quotes Henry Cavendish on this from ~1800: "To find the bending of a ray of light which passes near the surface of any body by the attraction of that body"