> "General relativity is just a model." Everything in physics a model. Quantum mechanics, electromagnetism, Newton's laws... Arguably everything in science is

> "General relativity is just a model." Everything in physics a model. Quantum mechanics, electromagnetism, Newton's laws... Arguably everything in science is a model. But at some point, a model does so well at explaining observations that we take it to be a Truth. At one point, genes were 'just a model/theory,' but after the discovery of DNA, we took them to be real and physical. Seen in this way, there's nothing circular about either case. It's uncontroversial to say that gravity is special because it is non-renormalizable. This means that one can't write down a quantum theory of gravity the same way that we write a quantum theory of electromagnetism, because it predicts infinite quantities that can't be removed from the theory. However string theory does unify quantum mechanics and gravity, and gravity is only "sort of special" in string theory (it does look in some ways like the other forces; the force carrier is the graviton). But exactly how spacetime emerges from string theory is still not fully understood.