  Most of the approaches to the construction of a theory of quantum gravity
share some principles which do not have specific experimental support up to
date. Two of these principles are relevant for our discussion: (i) the
gravitational field should have a quantum description in certain regime, and
(ii) any theory of gravity containing general relativity should be relational.
We study in general terms the possible implications of assuming deviations from
these principles, their compatibility with current experimental knowledge, and
how can they affect future experiments.
