[WikiEN-l] Types of categories

Sun Jun 4 21:01:26 UTC 2006

Steve Bennett wrote:
> 
> The problem there, now that I think about it, is that Paris should not
> be in the category "Paris" (as was pointed out by someone else).

Actually, if we consider "Paris" a thematic category, then it makes 
sense for Paris to be in it, since it certainly fits the theme.

But I do agree that the category "Paris" should not be a subcategory of 
"European capitals", since the things in the "Paris" category (with one 
possible exception) are not European capitals.

> Hmm, the difficulty is deciding what "subcategory" really means. I
> assume you're getting at the fact that a taxonomic subcategory should
> simply be getting more specific, and leading to more specialised
> subjects (so "Capitals of Europe" might have subcat "Capitals of
> Western Europe" or "Capitals of the European Union"), maintaining the
> "X is a Capital of Europe" mantra.
> 
> In this case, it would seem best that "Districts of Paris" was a
> category of the thematic category "Paris".

...which could, however, be a subcategory of "France", which in turn 
could be a subcategory of "Europe" -- all of these being thematic 
categories, and each theme being a subset of its parent theme.

In fact, we _could_ have a parallel taxonomic category tree that focused 
  solely on geography, with "Districts of Paris" being a subset of 
"Places in Paris", which in turn is a subset of "Places in France" (but 
_not_ "Cities in France") and "Places in Europe" and ultimately 
"Places".  So we'd have a tree of taxonomic "Places in [Region]" 
categories, each one having subcategories named either "[Divisions] in 
[Region]" or "Places in [Subregion]", with the root of the tree being 
"Places".  (I'm torn on whether we'd need a second-level category 
"Places on Earth", though.)

So, to summarize what I believe has been proposed:

Taxonomic categories (plural):
  * Subcategories are subsets (and always taxonomic).
  * Members are instances.

Thematic categories (singular):
  * Subcategories are subthemes (thematic) or sets of related things 
(taxonomic).
  * Members are related things.

The plural/singular distinction may not be ideal, but does feel very 
natural in many cases.  It's not without problems, though: what about, 
for example, the category "Sheep"?

-- 
Ilmari Karonen