Every other ontology mixes humans with fictional characters and with groups of humans and possibly fictional humans (biblical characters for instance). Wikidata has gone to a lot of trouble to try to untangle these into separate classes. Anyone trying to get an exhaustive list of humans and not using <instance of:human> deserves everything he gets.
P21 (sex or gender) is very explicitly specified as being usable for humans and for other creatures. At the request of some languages we have separate items for 'female human' and for 'female creature' (we have the same for male), 'Female human' is 'subclass of:female creature'. Relying on P21 to tell if something is or is not human is not recommended as it will probably miss out all the humans who are neither male nor female - wikidata has about a dozen other values that can be used with this property.
Father (P22) and mother (P25) can perfectly well be used for non-humans and if the current constraints on these properties flag this as a problem then the constraints will have to be updated. I expect to see extensive pedigrees for racehorses entered in Wikidata. Note that there is a proposal under consideration to replace P22 and P25 with a single 'parent' property.
Joe
On mið 26.ágú 2015 13:58, Peter F. Patel-Schneider wrote:
> I don't think that P21 (https://www.wikidata.org/wiki/Property:P21, sex or
> gender) is a subclass of P31 (https://www.wikidata.org/wiki/Property:P31,
> instance of). Properties aren't subclasses in general.
>
> Perhaps you meant to talk about https://www.wikidata.org/wiki/Property:P21
> (sex or gender) being related via (https://www.wikidata.org/wiki/Property:P31
> (instance of) to https://www.wikidata.org/wiki/Q18608871 (Wikidata property
> for items about people). This indicates that the property should only be
> used on people, even though the description of the property itself talks about
> its use on animals.
>
> It appears that Wikidata is not very consistent internally.
>
> peter
>
Sorry, I'm not used to the Wikidata lingo.
To further explain my point (to which I think you have already agreed to):
If I were to produce a code which makes assumptions based on such
relations, the code would come to the contradiction that a non-human
with a P21 relation is a human, if it were to recursively travel via in
the hierarchy of declarations. P21 is declared with a P31->Q18608871 and
Q18608871 is in turn declared P1269->Q5. Unless special precautions
would be taken, anyone trying to generate an exhaustive list of all
humans on Wikidata (without relying solely on the direct declaration on
each item), they might find themselves with non-humans on that list due
to travelling backwards via such relations.
In essence, it seems like P21 either wrongfully allows definitions of
genders of non-humans or that the property is too broad for a
declaration of P31->Q18608871.
- Svavar Kjarrval
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