Because of emergence. Unintuitive properties that arise from the aggregate interactions of discrete entities. Temperature is an emergent property arising from t

Because of emergence. Unintuitive properties that arise from the aggregate interactions of discrete entities. Temperature is an emergent property arising from the movement of all atoms within a space. There are no hot and cold atoms. The graviton doesn't exist. Gravity emerges from the interaction of matter (energy?) with spacetime. They are literally inseparable in our version of the universe. For those still looking for the graviton, the reasoning has led to the realization that you would create a black hole if you made the device that could detect it (as I understand it).