Cycorp welcomes you to its first major public release: approximately 3,000 terms capturing the most general concepts of human consensus reality. We refer to this as the "upper Cyc® ontology." The full Cyc® knowledge base (KB) includes a vast structure of more specific concepts descending below this upper level. Over the past dozen years, we have also entered into Cyc® literally millions of logical axioms -- rules and other assertions -- which specify constraints on the individual objects and classes found in the real world. Further specializations have been developed for our customers, especially in recent years, driven by their application needs. Thus, only a few percent of Cyc's terms appears in this release (and with only a small portion of their content). Later on, on the next page, we give a more detailed list of the parts of Cyc® omitted from this public release.
But we believe these 3,000 terms to be of great importance, interest, and use. Why? Because it is the core of an ontology that satisfies these two important criteria:
We do not make this claim lightly. Our conviction is based on person-centuries of effort expended over the past dozen years in constructing the Cyc® KB and applications using it. Our selection of Cyc's upper-level concepts has been tested in the crucible of extensive logical deduction on tens of millions of examples. In that process, many categories and functions that initially seemed useful proved not to be (like #$CompletelyTangibleObject and #$transfersThrough), while other "uglier" categories and functions (like #$SiblingDisjointCollection and #$SkolemFunction) emerged as surprisingly powerful and cost-effective and long-lived. Thousands of our most important discoveries are here and now made available to others.
The Upper Cyc® Ontology provides a sufficient common grounding for applications of the following types:
Every new concept will have some related concepts somewhere in the upper Cyc® ontology. One does not just add a new term to the ontology, one states assertions about it that serve to "situate" that new concept properly in the existing ontology. This does not, however, mean fully defining the new term; indeed, most of the terms worth having will never be precisely defined (e.g., "white collar worker.")
It is assumed that other systems will share the same upper ontology with Cyc® but diverge somewhat at lower levels, where more specialized terms are introduced and organized. That is neither a fundamental problem nor an obstacle to future integration of ontologies. Cf. our comments above, about Cyc® being universal and articulate. When concepts in other systems have been correctly mapped to their related concepts in the upper Cyc® ontology, differences should be confined to small, subject-related areas in which there may be some divergence in definitions.
And, most importantly, Cyc® permits (and even expects) its knowledge to be structured into lattices of reified, formalized, "first class" contexts. Such Cyc® "microtheories" can represent different points of view, levels of granularity, cultural differences, age differences, time periods, corporate cultures, etc.
For example, ten idiosyncratic and mutually inconsistent "models" for the US economy could be accommodated within Cyc® as ten separate microtheories, whose local collections and relations would all link upwards to appropriate generalizations in the upper Cyc® ontology. In each of those microtheories, terms would have different (partial) definitions, different rules which were stated about them, different assumptions that were presumed to hold true, etc.
We provide several tools to assist readers in becoming familiar with the upper Cyc® ontology, as the next page explains:
Please let us know if you are trying to include some concept that doesn't seem to be readily accommodated in the upper Cyc® ontology, or if you find one of the existing terms' comments unintelligible. For more information about Cycorp, and the Cyc® technology, click here.
We're excited about publishing the Upper Cyc® Ontology, and hope that you find it useful.
--- the Cycorp technical staff
We have prepared this document as a set of HTML pages. The first page, after this cover letter, is "The Cyc® Ontology Guide: Introduction". We will shortly be making even more of the Upper Cyc® Ontology available, publicly, along with downloadable cgi code for browsing through the hierarchies on your local machine. For now, such things are available to Cycorp customers and strategic partners. We wish to thank IBM in particular for sponsoring the preparation of Release 1.0 and 2.0.