[om-list] Facet based classification

[Mark Butler]

Hello everybody,

  I fundamentally agree with the idea behind "facet based" classification.  A strict hierarchical classification system (i.e. forced single inheritance) is hopelessly inflexible for any comphrensive model of knowledge.  Any real world object may be classified by an arbitrary number of dimensions, and  any normative hierarchical classification system applies a fixed number of them in a fixed order to any given object.

Tom has developed a model that is very useful.  Any given object or abstraction may be thought to occupy a point, or more generally a region, in a multi-dimensional space where each attribute of an object gives it a position or extent in one or more corresponding dimensions.

The most obvious dimensions are space and time.  Position and extent in space and time are obvious attributes of every real world object.  Most classifications are based on much more subtle dimensions, however.  For example, the plant-ness or animal-ness of a living organism.  While most existing examples fall clearly on one side or the other, I dare say there is no definition of a plant that has no ambiguity with the corresponding definition of an animal, and vice versa.

Now of course, as a matter of philosophical realism, neither plants nor animals care one way or the other. Plant-ness or animal-ness is a mental distinction we have adopted that can't be said to be *real*, i.e. to have an independent existence outside of our own minds, even though it clues us in to properties that are real, such as mobility and intelligence.

There lies the death of normative my-way-or-the-highway hierarchical classification systems - basically they are mental conveniences that often tell us more about one way of thinking about reality than about reality itself.  Now while modeling beliefs about reality is unavoidable, great care should be taken not to "hard-code" one belief system or world view into a comprehensive model of knowledge, largely because all mortal world views, or schemas, are strictly works in progress, even if most aspects are known to a high degree of certainty.

Tom and I would like to see a system with analytical capabilities as well as representational capabilities.  A very simple example would be to determine given an organism with various properties, how plant-like or animal-like it is.  That requires a logical model of the organism in question and a way to relate it to logical models of what it means to be a plant or an animal.  Dimensional analysis seems to be a good general purpose way to get started.

A classic complex example is determining to what degree one event was *caused* by another event. I.e. did the assassination of the Archduke of Austria cause World War I, or was it largely incidental to a dispute ready to boil over at any decent provocation?  Of course, that is an exceedingly complex question that requires an enormous amount of evidence to come to a reasonable conclusion about, but variations on the same theme are a topic of major academic and practical interest.

Fault detection and classification in everything from car engines to a complex industrial processes is a field of enormous practical importance where the necessary information for rational conclusions is much more readily available.

On the more theoretical side, in rigorous disciplines like mathematics, it is reasonably straightforward to construct simple theorem provers as well as proof checkers.  Most logical arguments are considerably more fuzzy than mathematical proofs, but I believe that there is a reasonable basis for analyzing well ordered bodies of knowledge according to time honored principles of logic, probability, and statistics, to the degree that such a system can help identify and demonstrate major logical flaws in (or at least the unmentioned premises behind) much of what passes for knowledge these days.  Dimensional analysis functions as an effective way to transform normal natural language definitions and statements into a model suitable for such calculations.

 - Mark