  Since the advent of quantum mechanics we have mainly been concerned with its
predictions from the perspective of an external observer. This is in strong
contrast to the theory of general relativity, where the physics is governed by
the intrinsic properties of space-time. At the same time, the precise relation
between space-time and quantum mechanics is still one of the greatest problems
of theoretical physics. This immediately raises the question on the
completeness of our understanding of quantum mechanics. Here we address the
problem by making an intrinsic analysis of observables in generic quantum
systems. We show that there is an extreme fine tuning problem for the emergence
of physics from the Hilbert space dynamics. However, for any initial condition
and Hamiltonian, there exists a special set of observables. We show that these
observables are intimately linked to the natural configuration space in which
an area law for the entanglement is inevitable. We argue that this implies
emergent gravity.
