  It will be shown in this article that an ontological approach for some
problems related to the interpretation of Quantum Mechanics could emerge from a
re-evaluation of the main paradox of early Greek thought: the paradox of Being
and non-Being, and the solutions presented to it by Plato and Aristotle.
Plato's and Aristotle's systems are argued here to do on the ontological level
essentially the same: to introduce stability in the world by introducing the
notion of a separable, stable object, for which a principle of contradiction is
valid: an object cannot be and not-be at the same place at the same time. After
leaving Aristotelian metaphysics, early modern science had to cope with these
problems: it did so by introducing ``space'' as the seat of stability, and
``time'' as the theater of motion. But the ontological structure present in
this solution remained the same. Therefore the fundamental notion `separable
system', related to the notions observation and measurement, themselves related
to the modern concepts of space and time, appears to be intrinsically
problematic, because it is inextricably connected to classical logic on the
ontological level. We see therefore the problems dealt with by quantum logic
not as merely formal, and the problem of `non-locality' as related to it,
indicating the need to re-think the notions `system', `entity', as well as the
implications of the operation `measurement', which is seen here as an
application of classical logic (including its ontological consequences) on the
material world.
