Gravitation : the most fundamental interaction

The comprehensive analysis by Niels Bohr shows that the classical world is a necessary additional independent structure not derivable from quantum mechanics. The results of measurement must be expressed classically; there must be a classical region of every experiment where physicists can set apparatus, read pointers and so on. As we will see, the events constituting spacetime of general relativity is this classical structure. Hence, gravitation is required to make the formal quantum mechanical coexistence of many mutually incompatible possibilities result in the concrete reality of the normal world, making gravitation the most fundamental interaction. It also means that “Quantum Gravity” is a pseudo-problem, a mirage, “Quantum Spacetime” an oxymoron