Introduction

Ontology has experienced a renaissance recently. In the past, it has been used as a term for probably the most fundamental branch of metaphysics, the study of being or existence, the most fundamental study of reality, the science of ``being qua being''. In computer science it refers to the formalization of all the relevant entities, relationships and rules of a domain, usually in a hierarchical data structure. Ontologies are used in branches of artificial intelligence and knowledge representation. They can be used for inductive reasoning or classification, or the communication and sharing of information between different systems. Most ontologies in use today are limited to a single domain, like the Gene Ontology, that is limited to the domain of genes. Ontologies, that are not limited to specific domains are called Top-Level-Ontologies, Upper Ontologies or Foundation Ontologies. They try do define general entities in a general sense. This can be highly valuable for common sense reasoning or as a foundational background for domain specific ontologies. Some claim, that this leads to ``semantic and ontological warfare due to competing standards'', mostly due to different philosophical views on what exists. There are several projects that develop an Upper Ontology, one of them is the GOL group in Leipzig with their GFO, General Formal Ontologies. This work is a contribution to the General Formal GOLGeneral Ontological Language. A language to formalize ontologies. GOL uses GFO as a background ontology. GFOGeneral Formal Ontologies. A library of top-level ontologies. Ontologies. Due to different fundamental, philosophical views, probably no Top-Level-Ontology will ever become a single, widely accepted standard, and even in this work there will be decisions made that contradict some of the decisions already made by the designers of the General Formal Ontologies. Some of them will be minor, and could or could not be integrated in GFO. Some may be more important, and as we will try to defend our decisions thoroughly, we encourage the GOL researchers to use our argumentation to improve their ontology framework. This is to say, that this thesis will not be limited by the decisions already made by the GOL group. If there is enough evidence to justify this step, we will argue in favor of philosophical views different to those expressed in the General Formal Ontologies.