On 29/05/14 12:41, Thomas Douillard wrote:
@David:<https://www.wikidata.org/wiki/Q224821>:)
I think you should have a look to fuzzy logic
Or at probabilistic logic, possibilistic logic, epistemic logic, ... it's endless. Let's first complete the data we are sure of before we start to discuss whether Pluto is a planet with fuzzy degree 0.6 or 0.7 ;-)
(The problem with quantitative logics is that there is usually no reference for the numbers you need there, so they are not well suited for a secondary data collection like Wikidata that relies on other sources. The closest concept that still might work is probabilistic logic, since you can really get some probabilities from published data; but even there it is hard to use the probability as a raw value without specifying very clearly what the experiment looked like.)
Markus
<mailto:dacuetu@gmail.com>>:Wikidata-l@lists.wikimedia.org <mailto:Wikidata-l@lists.wikimedia.org><mailto:markus@semantic-mediawiki.org>> wrote:
This is an easy question once you have been clear about what
"human behaviour" is. According to enwiki, it is a "range of
behaviours *exhibited by* humans".
Settled :) Let's leave it at <defined as a trait of>
What would anybody do with this data? In what application could
it be of interest?
Well, our goal it to gather the whole human knowledge, not to use
it. I can think of several applications, but let's leave that open.
Never underestimate human creativity ;-)
Moreover, as a great Icelandic ontologist once said: "There is
definitely, definitely, definitely no logic, to human behaviour" ;-)
Definitely, that is why we spend so much time in front of flickering
squares making them flicker even more. It makes total sense :P
I think "constraints" are already understood in this way. The
name comes from databases, where a "constraint violation" is
indeed a rather hard error. On the other hand, ironically,
constraints (as a technical term) are often considered to be a
softer form of modelling than (onto)logical axioms: a constraint
can be violated while a logical axiom (as the name suggests) is
always true -- if it is not backed by the given data, new data
will be inferred. So as a technical term, "constraint" is quite
appropriate for the mechanism we have, although it may not be
the best term to clarify the intention.
Ok, I will not fight traditional labels nor conventions. I was
interested in pointing out to the inappropriateness of using a word
inside our community with a definition that doesn't matches its use,
when there is another word that matches perfectly and conveys its
meaning better to users.
Some important ideas like classification (instance of/subclass
of) belong completely to the analytical realm. We don't observe
classes, we define them. A planet is what we call a "planet",
and this can change even if the actual lumps in space are pretty
much the same.
Agreed. Better labels could be <defined as instance of>/<defined as
subclass of>
Now inferences are slightly different. If we know that X implies
Y, then if "A says X" we can infer that (implicitly) "A says Y".
That is a logical relationship (or rule) on the level of what is
claimed, rather than on the level of statements. Note that we
still need to have a way to find out that "X implies Y", which
is a content-level claim that should have its own reference
somewhere. We mainly use inference in this sense with "subclass
of" in reasonator or when checking constraints. In this case,
the implications are encoded as subclass-of statements ("If X is
a piano, then X is an instrument"). This allows us to have
references on the implications.
Nope, nope, nope. I was not referring to "hard" implications, but to
heuristic ones.
Consider that these properties in the item namespace:
<defined as a trait of>
<defined as having>
<defined as instance of>
Would translate as these constraints in the property namespace:
<likely to be a trait of>
<likely to have>
<likely to be an instance of>
In general, an interesting question here is what the status of
"subclass of" really is. Do we gather this information from
external sources (surely there must be a book that tells us that
pianos are instruments) or do we as a community define this for
Wikidata (surely, the overall hierarchy we get is hardly the
"universal class hierarchy of the world" but a very specific
classification that is different from other classifications that
may exist elsewhere)? Best not to think about it too much and to
gather sources whenever we have them ;-)
I think it is good to think about it and to consider options to deal
with it. Like for instance:
<defined as instance of> "corresponds with item" <Wikimedia
community concept>
We already have items that refer to concepts that only make sense
for us, so no change in that regard.
At the moment, hard constraints (from definitions) and soft
constraints (expectations) are simply mixed, and maybe this is
fine since we handle them in a similar fashion (humans need to
look how to fix the situation). Most constraints, even those
that refer to definitions, are rather soft anyway since we apply
them to statements, not to hard facts. Hard constraints can only
occur in cases where the *encoding* of a statement in Wikidata
is wrong (not the intended statement as such, but how it was
translated to data).
As explained above, expectations inferred from definitions should
not be treated as hard constraints, but as soft ones.
Micru
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