  According to many researchers, conceptual model (CM) development is a hard
task, and system requirements are difficult to collect, causing many
miscommunication problems. CMs require more than modeling ability alone - they
first require an understanding of the targeted domain that the model attempts
to represent. Accordingly, a preconceptual modeling (pre-CM) stage is intended
to address ontological issues before typical CM development is initiated. It
involves defining a portion of reality when entities and processes are
differentiated and integrated as unified wholes. This pre-CM phase forms the
focus of research in this paper. The purpose is not show how to model; rather,
it is to demonstrate how to establish a metaphysical basis of the involved
portion of reality. To demonstrate such a venture, we employ the so-called
thinging machine (TM) modeling that has been proposed as a high-level CM. A TM
model integrates staticity and dynamism grounded in a fundamental construct
called a thimac (things/machine). It involves two modes of reality, existence
(events) and subsistence (regions - roughly, specifications of things and
processes). Currently, the dominant approach in CM has evolved to limit its
scope of application to develop ontological categorization (types of things).
In the TM approach, pre-CM metaphysics is viewed as a part and parcel of CM
itself. The general research problem is how to map TM constructs to what is out
there in the targeted domain. Discussions involve the nature of thimacs (things
and processes) and subsistence and existence as they are superimposed over each
other in reality. Specifically, we make two claims, (a) the perceptibility of
regions as a phenomenon and (b) the distinctiveness of existence as a construct
for events. The results contribute to further the understanding of TM modeling
in addition to introducing some metaphysical insights.
