  We examine the conditions under which the thermodynamic behaviour of gravity
can be explained within an emergent gravity scenario, where the metric is
defined as a composite operator. We show that due to the availability of a
boundary of a boundary principle for the quantum effective action,
Clausius-like relations can always be constructed. Hence, any true explanation
of the thermodynamic nature of the metric tensor has to be referred to an
equilibration process, associated to the presence of an H-theorem, possibly
driven by decoherence induced by the pregeometric degrees of freedom, and their
entanglement with the geometric ones.
