A Survey of Top-level Ontologies

Summary

We have developed a list of candidate TLOs – there are currently thirty seven listed in Appendix D (with ten more waiting in a queue to be analysed) and this will be updated as new TLOs are found. This provides a reasonably comprehensive picture of what is currently available.

We have developed a framework for providing an overarching top-down picture of the TLOs. This has three parts. It starts by looking at the general choices; whether to explicitly make ontological commitments and if so, whether to focus on natural language or the real world. It then looks at the formal structure. Finally, it reviews the range of choices of universal ontological commitments typically encountered in TLOs.

The formal structure is divided into two aspects. Firstly, the vertical aspects – the different kinds of formal structures that arise from the core ontological relations. Then the horizontal aspects – the different stratification and unifying choices driven by ontological commitments. The results of this assessment are in the previous section.

• Whether or not a wide range of framework choices have been made is a good indicator of the level of ontological commitment.
  • TLOs with a heavyweight ontological commitment, understandably, tend to explicitly, or otherwise, make a majority of the framework choices.
  • TLOs with a lightweight ontological commitment, understandably, tend to explicitly, or otherwise, make a minority of the framework choices.
  • Generic TLOs that have avoided explicit ontological commitment, often have clear vertical aspects in their formal structure, perhaps indicating the importance of these choices.
• For the horizontal stratifying aspects, there is a general tendency for the heavyweight TLOs to either stratify or unify. This is a similar pattern to that found in philosophy, where stratifying (or unifying) choices tend to reinforce one another.

We have included in Appendix F a brief summary of the TLOs with, where available, a hierarchical picture of their top-most level. We have also added comments on particular details. A quick review of the hierarchical pictures reveals the vast range of top-level structures in current use. A comparison of the lightweight and heavyweight TLO hierarchies, still reveals a wide range of structures. The assessment framework helps to give some idea of where these are based on similar commitments and where they have different commitments.

The results of this survey will be used to perform a structured assessment of the TLOs identified herein, with a view to selecting one or more TLOs that will form the kernel around which the FDM will evolve. A further report – The FDM TLO Selection Paper – will be issued to describe this process in late 2020.

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Continue to next section: Appendix A - Pathway requirements for a Foundation Data Model