d>

SNAP and SPAN: Prolegomenon to Geodynamic Ontology 1
SNAP and SPAN:
Prolegomenon to Geodynamic Ontology
1


Pierre Grenon
a
(pgrenon@ifomis.uni-leipzig.de)

Barry Smith
a,b
(phismith@buffalo.edu)


a
IFOMIS, University of Leipzig, Germany
b
Department of Philosophy, University at Buffalo, NY 14260, USA


Preprint version of a paper forthcoming in Spatial Cognition and Computation


Current approaches to the formal representation of geographical reality are
characterized by their static character. GIS representations are
representations of the world at a given time, reflecting the fact that
geographic information systems have their roots in printed maps. Yet,
geographical reality, like all other domains of reality, is essentially dynamic.
We here outline a theory that is designed to preserve what is of value in
current representation schemas while addressing the need for dynamics. Our
position is that a good ontology must be capable of accounting for reality
both synchronically (as it exists at a time) and diachronically (as it unfolds
through time), but that these are two quite different tasks. Our approach is
capable of accomplishing this via what might be described as a joint venture
between the so-called three-dimensionalist and four-dimensionalist
perspectives current in contemporary philosophical ontology. Briefly, we
shall propose a modular formal ontology with two components, one for
geographic objects and one for geographic processes.


1 Introduction
Reality is described in the first place by means of natural language. But natural language is
of course not without its defects as a tool for description. In order to understand and
safeguard against such defects we need a standard of correctness, some ground for speaking
about reality which means a theoretical understanding of reality as it is in itself. It is just
such a theoretical understanding which ontology in the philosophical sense is designed to
provide. Ontology in this sense concerns itself with the question of what there is. It
purports to produce an account of the token entities existing in the world, of the types or

1
This work was supported by the Alexander von Humboldt Foundation under the auspices of its Wolfgang
Paul Program and also by the National Science Foundation Grant BCS-9975557: Geographic Categories; An
Ontological Investigation. 2
categories under which these entities fall, and of the different sorts of relations which hold
between them.

This philosophical task of working out the types and relationships among entities
must of course at some point join up with the work of scientists. The full task of ontology is
then a matter of going back and forth between the formulation of philosophical theories on
the one hand and the testing of such theories against what we know about reality, above all
from the work of scientists, on the other.

Ontology produces theories about the world formalized in some logical language.
Such a theory typically includes a taxonomy of categories with accompanying axioms and
definitions. The virtue of formalization is first of all that of enforcing a certain degree of
clarity. Another virtue is that it makes theories readily accessible, evaluable, and re-usable
by other communities of researchers. Additionally, formalization makes it possible for us to
exploit some of the power of logic when using ontologies in reasoning systems.

Methodology. Our methodology, defended in (Smith, 2003) and (Grenon, 2003a), is realist,
perspectivalist, fallibilist, and adequatist. Realism asserts that reality and its constituents
exist independently of our (linguistic, conceptual, theoretical, cultural) representations
thereof. Perspectivalism maintains that there may be alternative, equally legitimate
perspectives on this reality. Perspectivalism is then constrained by realism: thus it does not
amount to the thesis that just any view of reality is legitimate. To establish which views are
legitimate we must weigh them against their ability to survive critical tests when
confronted with reality, for example via scientific experiments. Those perspectives which
survive are deemed to be transparent to reality. This is however in a way that is always
subject to further correction. It is a fact that sciences change with time, and thus everything
that is said here must be understood against the background of fallibilism, which accepts
that both theories and classifications can be subject to revision. Adequatism, finally, is the
negation of reductionism in philosophy. The reductionist affirms that, among the plurality
of alternative views of reality there is some one basic view to which all the others can be
reduced. We, in contrast, affirm that there are many views of reality, all of which are
equally veridical. These are views of entities in different domains or of entities as seen
from different perspectives or they are views of what exists on different levels of
granularity (microscopic, mesoscopic, geographic). Adequatism is the doctrine that a
plurality of such views is needed if we are to do justice to reality as a whole.

An adequatist approach to ontology with ambitions to remain consistent with
science will need to be very cautious in sorting out the needed repertoire of mutually
complementary perspectives. One perspective might accept as an unchallenged truth the
reality of this cup or that chair. Another might seek to do justice to the very same reality in
terms of aggregates of atoms or molecules. A third might talk in terms of changes and
invariants in the spatiotemporal continuum. Adequatism means that all of these views are
tenable within their respective boundaries, and that there is no privileged approach which
could justify the reduction of one to another. Adequatism allows us to embrace
simultaneously both commonsensical and scientific realism, that is: it allows us to endorse
the view that both common sense and science can grant us genuine knowledge of the world.
3
Formal and Material Ontology. It was Husserl in his Logical Investigations (1913/21) who
first drew a clear distinction between two kinds of ontological inquiry. On the one hand is
what he called formal ontology, which is a theory at the highest and most domain-neutral
level. Formal ontology deals with the categories and relationships which appear in all
domains and which are in principle applicable to reality under any perspective (with some
possible additions or subtractions in specific domains or levels). Examples of such
categories include: object, relation, group, number, part-of, identical-to. On the other hand
are what Husserl called material or regional ontologies, which are the ontologies of
specific domains. There are as many ontologies in this sense as there are subject matters or
domains of inquiry. Examples of such domains were for Husserl the domain of space, time
and physical things; the domain of organisms; the domain of mind; and the domain of
societies.

1.1 Basic Formal Ontology
Basic Formal Ontology (BFO) is a theory of the basic structures of reality currently being
developed at the Institute for Formal Ontology and Medical Information Science (IFOMIS)
in the University of Leipzig. BFO is a formal ontology in the sense of Husserl and its
construction follows the methodological maxims presented above. The enterprise of
building BFO is thus motivated on the one hand by the desire to be truthful to reality, and
on the other hand by the need to accept a multiplicity of perspectives upon reality which
may be skew to each other. IFOMIS and its associates are developing a series of material or
regional ontologies, including: MedO (for Medical Ontology), GeO (for Geographical
Ontology), and DisReO (for Disaster Relief Ontology).

As a formal ontology BFO serves
as a reusable template, which can (with some modifications) be used in constructing
material ontologies for any and all domains of entities.

Temporal Modes of Being. The central dichotomy among the perspectives represented in
BFO concerns the modes of existence in time of the entities populating the world. BFO
endorses first of all a view according to which there are entities in the world that have
continuous existen