Since its inception ten years ago, the International Conference on Formal Ontology in Information Systems (FOIS) has explored the multiple perspectives on the notion of ontology that have arisen from such diverse research communities as philosophy, logic, computer science, cognitive science, linguistics, and various scientific domains.

As ontologies have been applied in new and exciting domains such as the World Wide Web, bioinformatics, and geographical information systems, it has become evident that there is a need for ontologies that have been developed with solid theoretical foundations based on philosophical, linguistic, and logical analysis. Similarly, there is also a need for theoretical research that is driven by the issues that have been raised by recent work in the more applied domains. FOIS is intended to be a forum in which to explore this interplay between the theoretical insights of formal ontology and their application to information systems and emerging semantic technologies. The papers appearing in this year's conference exemplify this interaction in very interesting ways, with papers covering the range from foundational issues and generic ontologies to methodologies for ontological engineering, reasoning, and ontology integration.

Themes emerging from the papers give us a snapshot of current issues within the fields of formal ontology and ontological engineering, as well providing us with a glimpse of future research directions.

Although ontologies were originally motivated by the need for sharable and reusable knowledge bases, the reuse and sharing of ontologies themselves is still limited because the ontology users (and other designers) do not always share the same assumptions as the original designers. It is difficult for users to identify implicit assumptions and to understand the key distinctions within the ontology and whether or not disagreements reflect fundamentally different ontological commitments. The challenge therefore still stands to propose ontological engineering methodologies that emphasize ontology reuse and that identify the characteristics of an ontology that enhance its reusability.

The interaction between ontology and science has emerged as an interesting new theme. First, ontologies can be treated as scientific theories, rather than as engineering artefacts. Second, there are ontologies for scientific theories, such as biology and chemistry, which play a role in integrating multiple data sets. Finally, there is work on developing ontologies of scientific theories; such ontologies play a supporting role in scientific research by providing explicit representations for alternative theories. This is also interesting insofar as one can consider ontologies for scientific domains to be a proposed solution for the sixth of twenty-three challenge problems posed by David Hilbert in an address to the International Congress on Mathematicians in 1900:

Mathematical treatment of the axioms of physics:

The investigations on the foundations of geometry suggest the problem: To treat in the same manner, by means of axioms, those physical sciences in which mathematics plays an important part.

The identification and logical formalization of fundamental ontological distinctions continues to be an impetus for current research. Fundamental distinctions, such as universals vs. particulars, features vs. substrates, and artefacts vs. roles are still a source of many challenging problems. Many of these issues converge in unexpected ways, particularly in the treatment of collective objects. Linguistic expressions have also motivated several areas in formal ontology, particularly in the areas of vague predicates and geographic terminology.

Ontology evaluation, both from a logical and empirical perspective, has also been recognized as a critical phase in ontological engineering. On the one hand, this leads to a deeper understanding of the relationships between ontologies. As ontologies are increasingly being deployed on the web, users are faced with the dilemma of selecting amongst multiple possible ontologies for similar domains. On the other hand, ontology evaluation is based on the relationship between the ontology and its initial conceptualization and intended application. We can rigorously characterize the relationship between the intended models of the ontology and the models of the axiomatization of the ontology, but it is more difficult to evaluate the correspondence between the intended models and their adequacy for the intended application of the ontology.

Finally, the widespread deployment of ontologies also raises the challenge of managing discrepancies that arise between ontologies. Although this is most evident in applications that require the integration of multiple domain (and possibly upper) ontologies, the problem must also be addressed by end users who want to merge concepts from multiple ontologies to create new ontologies that meet the specific needs of some domain. Integrating sets of independently designed ontologies also has ramifications for supporting automated reasoning with the ontologies.

The success of FOIS-08 has been the result of a truly collaborative effort. We would like to thank the members of the Programme Committee for their diligent work and constructive feedback, which have contributed to an excellent conference programme. We would like to thank the three invited speakers, Johanna Seibt, York Sure, and Mike Uschold, for providing their interesting perspectives on formal ontology in information systems. Finally, we would like to thank the Conference Chair, Nicola Guarino, and the Local Chairs, for managing all of the details that have made the conference a productive interaction of researchers from the diverse disciplines that contribute to formal ontology.

Carola Eschenbach

Michael Grüninger