  Referring to the 18th century idealism of George Berkeley in which an object
exists if and only if it is observed, this note shows that orthodox quantum
mechanics (OQM) entails a Berkelian idealism regarding properties (BIRP): a
quantum `has' a property X with quantitative value x if and only if the
property X has just been measured with outcome x. It is then impossible to
recontextualize GR's principle of curvature in any quantum framework that
implies this BIRP, for a quantum cannot curve space-time if it doesn't have a
definite energy - which is supposed to be the cause of curvature - in absence
of observation to begin with. Concluding, it is ruled out that a quantum theory
of gravity, in which GR's principle of curvature is built in as a fundamental
physical principle, can be developed in any framework implying this BIRP.
