 
Summary: Relativity Theory: what is Reality?
Diederik Aerts
Center Leo Apostel, Brussels Free University
Krijgskundestraat 33, 1160 Brussels
email: diraerts@vub.ac.be
Abstract
In classical Newtonian physics there was a clear understanding of 'what
reality is'. Indeed in this classical view, reality at a certain time is the
collection of all what is actual at this time, and this is contained in 'the
present'. Often it is stated that three dimensional space and one di
mensional time have been substituted by four dimensional spacetime in
relativity theory, and as a consequence the classical concept of reality, as
that what is 'present', cannot be retained. Is reality then the four dimen
sional manifold of relativity theory? And if so, what is then the meaning
of 'change in time'? This problematic confronts a geometric view (as the
Einsteinian interpretation of relativity theory) with a process view (where
reality changes constantly in time). In this paper we investigate this prob
lem, taking into account our insight in the nature of reality as it came by
analyzing the problems of quantum mechanics. We show that with an
Einsteinian interpretation of relativity theory, reality is indeed four di
