  The developments of special relativity and quantum mechanics marked the
beginning of the modern physics age. The former has taught us that while space
and time are frame dependent notions, there is a quantity -- the space-time
interval -- whose value all inertial observers agree upon. This reveals, so to
speak, a genuine "fact" of the universe, a relativistic invariant. On the other
hand, since the dawn of quantum mechanics, there is no consensus on what the
theory is all about. The situation is admittedly subtler: quantum theory is
grounded on a complex vector space and the very notions of observer and
reference frame are controversial. Here we construct a theoretical framework
within which a given combination of quantum resources is shown to be a Galilean
invariant. To this end, we postulate a principle of relational symmetry between
"the observer" and "the observed" and employ the notion of quantum reference
frame. Unitary transformations then follow that allow us to perceive the
physical resources seen from the viewpoint of any quantum system.
Interestingly, we find that one needs more than quantum coherence and quantum
correlations to prove quantum resources covariance. Finally, we show that the
notion of physical reality implied by quantum mechanics is not absolute.
