  The notions of time in the theories of Newton and Einstein are reviewed so
that the difficulty which impedes the unification of quantum mechanics (QM) and
general relativity (GR) is clarified. It is seen that GR by itself contains an
intrinsic difficulty relating to the definition of local clocks, as well as
that GR still requires a kind of absolute that can serve as an objective
reference standard. We present a new understanding of time, which gives a
consistent definition of a local time associated with each local system in a
quantum mechanical way, so that it serves the requirements of both GR as well
as QM. As a consequence, QM and GR are reconciled while preserving the current
mathematical formulations of both theories.
