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. Hope this helps
Joe
On Wed, 26 Aug 2015 18:44 Svavar Kjarrval svavar@kjarrval.is wrote:
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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