I saw a post asking why don’t programmers use topic maps? I replied at the time but on reflection, I think the answer is simpler than I thought at the time.
What do ontologies, classification systems and terminologies all have in common?
Ontology
SUMO and Cyc are projects that would be admitted by most to fall under the rubric of “ontology.”
Classification System
The Library of Congress Subject Headings (LCSH) is an example of a classification system.
Terminology
SNOMED-CT self-identifies as a terminology, it makes a good example.
Substitute other projects that fall under these labels. It doesn’t change the following analysis.
What do these projects have in common?
SNOMED-CT and LCSH were both produced by organs of the U.S. government but SUMO and Cyc were not.
SUMO and Cyc both claim to be universal upper ontologies while SNOMED-CT and LCSH make no such claims.
All four have organizations that have grown up around them or fostered them. Is that a clue? Perhaps.
Question: If you had a question SUMO, Cyc, SNOMED-CT or LCSH, and need an authoritative answer, who would you ask?
Answer: Ask the appropriate project. Yes? That is only the maintainers of SUMO, Cyc, SNOMED-CT or LCSH can provide authoritative answers for their projects. Only their answers have interoperability with their systems.
Topic maps offer the capability to have decentralized authority over terms. While maintaining the use of extended terms across topic map systems.
I know, that didn’t read very smoothly so let me try to explain by example.
In Semantic Integration: N-Squared to N+1 (and decentralized) I demonstrated how four (4) different authors could have four (4) different identifiers for Superman and write different things about Superman.
As a topic map author I notice they are talking about the same subject and unknown to those authors, I create a topic that merges all of their information about Superman together.
Those authors may continue to write different information about Superman using their identifier, but anyone using my topic map will see all the information gathered together.
The same reasoning applies to SNOMED-CT and LCSH, both of which have medical classifications that are different. The medical community and their patients could wait until the SNOMED-CT and LCSH organizations create a mapping between the two, but there are other options.
A medical researcher who notices a mapping between terms in SNOMED-CT and LSCH, could mark that and future researchers (assuming they accept the mapping) would find information from either source, using either identifier, together. Creating sets identifiers is just that simple. (I lie, it would take a useful interface as well but that’s doable.
Note the difference in process.
In one case, highly bureaucratic organizations who have a stake in the use of “their” ontology/classification/terminology” make all the decisions about what maps are made and what those maps include.
In the topic map case, the person with the need for the information and expertise finds a mapping between information sources and adds in a mapping on the spot. A bread crumb if you will that may help future researchers with greater information than existed at that location before.
Oh, and one other issue, interoperability.
If you construct topic maps using the Topic Maps Data Model (TMDM) and one of the standard syntaxes, no matter what new material you add to it, it will work with other standard topic map software.
Try that with your local library catalog software for example.
The question isn’t why programmers aren’t using topic maps?
Topic maps enable decentralized decision making about information, without preset limits on that information, with interoperability by default.
The question is: Why aren’t you demanding the use of topic maps? (you have to answer that one for yourself)
Alt title: Topic Maps: Priesthood of the User
PS: Quite serious about the alt title. Remember when browsers were supposed to display webpages the way users wanted them? That didn’t last very long did it. Maybe we should have another go at it with information?