  The paper has heuristic character. The conceptual frame, based on the
assumption of quantum uncertainty only, has been formerly introduced in two
papers [S. Tosto, Il Nuovo Cimento B, vol. 111, n.2, 1996 and S. Tosto, Il
Nuovo Cimento D, vol. 18, n.12, 1996]. Instead of attempting to increase the
accuracy of some existing computational model through a new kind of
approximation, these papers acknowledge since the beginning the lack of
deterministic information about the local properties of the constituent
particles, considered random, unknown and unpredictable and thus ignored in
principle. The leading idea is that the physical properties of quantum systems
could be inferred merely considering the delocalization ranges of dynamical
variables, rather than their local values. In effect, despite the agnostic
character of the approach proposed, both papers show that the kind of physical
information reachable reproduces exactly in all cases examined that obtained
solving the pertinent wave equations. The concept of quantum uncertainty is
further extended in the present paper to both space and time coordinates,
considering thus a unique spacetime delocalization range and still discarding
since the beginning the local values of the conjugate dynamical variables. The
paper shows an unexpected wealth of information obtainable simply extending the
concept of space uncertainty to that of spacetime uncertainty: the results are
inherently consistent with that of the operator formalism of wave mechanics and
with the basic postulates of special relativity, both inferred as corollaries.
Moreover, even the gravity appears to be essentially a quantum phenomenon. The
most relevant outcomes of special and general relativity are achieved as
straightforward consequence of the space-time delocalization of particles using
the simple quantum formalism first introduced in the early papers.
