> 1) General relativity is just a model. Yes, but it is the currently accepted model. Whereas, for the other 3 fundamental interactions, the currently accepte

> 1) General relativity is just a model. Yes, but it is the currently accepted model. Whereas, for the other 3 fundamental interactions, the currently accepted model is in the form of a quantum field theory. For these 3 interactions, the models suggest force carrier particles, and these particles have been observed (electromagnetism: photon, weak interaction: bosons, strong interaction: gluons). People have tried to construct a quantum field theory -like model for gravity, which would include gravitons as the force carrier particles. But all these attempts have failed to produce a consistent theory, and also nobody has ever measured or observed gravitons, so this is all hypothetical. But if we get philosophical about this, gravity is not like other forces because the currently accepted model for gravity is not like the models for the other forces. Gravity is not a field with force carrier particles because we have not been successful at modelling it as such.