  We use a new distinctly "geometrical" interpretation of non-relativistic
quantum mechanics (NRQM) to argue for the fundamentality of the 4D blockworld
ontology. Our interpretation rests on two formal results: Kaiser, Bohr &
Ulfbeck and Anandan showed independently that the Heisenberg commutation
relations of NRQM follow from the relativity of simultaneity (RoS) per the
Poincare Lie algebra, and Bohr, Ulfbeck & Mottelson showed that the density
matrix for a particular NRQM experimental outcome may be obtained from the
spacetime symmetry group of the experimental configuration. Together these
formal results imply that contrary to accepted wisdom, NRQM, the measurement
problem and so-called quantum non-locality do not provide reasons to abandon
the 4D blockworld implication of RoS. After discussing the full philosophical
implications of these formal results, we motivate and derive the Born rule in
the context of our ontology of spacetime relations via Anandan. Finally, we
apply our explanatory and descriptive methodology to a particular experimental
set-up (the so-called "quantum liar experiment") and thereby show how the
blockworld view is not only consistent with NRQM, not only an implication of
our geometrical interpretation of NRQM, but it is necessary in a non-trivial
way for explaining quantum interference and "non-locality" from the spacetime
perspective.
