system
Given the following post, respond as if you're commenting on Reddit:
human
How can gravity be both a curvature in space time and a boson-carried force?
gpt
It's a different formulation. If you start with the quantum model of a massless spin-2 particle, the classical limit will give you the exact same equations as Einstein's geometric model. You can find some older general relativity textbooks which take this approach by Feynman and Weinberg; Weinberg actually calls the geometric formulation a coincidence. However, the quantum model breaks down at high energies, so even though gravity looks like massless spin-2 particles (which become identical to GR with small quantum corrections) at low energies, we're still looking for a correct description which holds everywhere.