[WikiEN-l] Types of categories

[Steve Bennett]

On 6/4/06, Roger Luethi <collector at hellgate.ch> wrote:
> > I've personally run into this when trying to automatically create, for
> > example, a list of all Wikipedia articles on people.  You can't just
> > start at [[category:people]] and work your way down, because you wind
> > up going to [[Category:Women]] (fine, all women are people) then
> > [[Category:Feminine hygene]] (bad).
>
> Okay, that's equivalent to Steve's Amelie-Paris relation. I agree that's a
> problem.

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).

Amelie should be in the category "Paris"
The article Paris should be in the category "European capitals" (say)
The article Paris should not be in the category "Paris"
The category "Paris" should not be in the category "European capitals".

Actually, even simply obeying this last rule would solve it: Paris
*the article* belongs in the taxonomic category (Paris *is a* European
capital) , but "Paris" the category is thematic, so should only belong
to thematic categories: maybe "Europe" in this case.

That actually seems to fix the problem. I saw this with The Beatles
for example. John Lennon was in category "The Beatles" (thematic), and
that category was in "British rock bands" (taxonomic), leading to the
conclusion that Lennon was a British rock band.

> But even if we maintained a complete and up-to-date system of subcats, we'd
> still make it hard for people to find articles using categories. For some
> fairly sensible reasons, the rule is to include articles only to the

I have never completely understood these "sensible reasons". It's
redundant from a taxonomic point of view, but since category
navigation works so badly (there is no way to easily see everything in
a category and all its subcats), it often seems to work well from a
practical perspective, so that the item actually shows up where you
expect it to.

It's ok if a category consists entirely of subcategories, but if there
are both articles and subcats in it, then not having an article in the
category by virtue of the fact that it's included in a subcat is
awkward and doesn't work well.

> subcategory, but not to the parent. There is no way to list articles based
> on a subset of criteria (the articles in subcategories are effectively
> hidden on separate pages which is only helpful if you know which one to
> pick).

Yep.

> The devil is in the details.
>
> For instance, how do you connect the districts of Paris to the category
> Paris? What is a subset of the parent attribute "Paris": "Districts of
> Paris", or "Quartier Latin", or neither? Does it bother you if the article
> on a French district is now in a subcategory of "Capitals in Europe"?

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".

> Or going back to [[Category:Women]]: You could declare that only articles
> on instances of women (i.e.  biographies) can ever be under that category,
> and that only sets of such articles can ever be subcategories of the
> category women. -- You could even create a separate [[Category:Woman]],

This is a perfect example of a problem aluded to in the MoS on
categories: Women is both a taxonomic category (it's a plural) and a
theme (eg, Women throughout the ages, or whatever). Disaster is
inevitable from that point onward.

The taxonomic category "Women" could be split immediately into
fictional women and real women, then into living and dead women, then
again by various means.
The thematic category "Women" could be broken into feminism, biology, etc etc.

> subcategories like "female reproductive organs" containing articles like
> uterus. -- But how would you express the undisputed relationship between
> female human beings and your example [[Category:Feminine hygiene]]? How
> about [[Category:Women's rights]]? Add an umbrella cat "Somehow related to
> women" maybe?

With a separate, thematic, category. What would you call it? I don't
know. In practice, this would probably only work through a whole
separate structure, leaving Categories only for taxonmic categories
("X is a Y"), and creating a structure called Subjects or Themes or
something.

Steve