Re: multisets everywhere

Dear Thomas, Dörthe, 

>>> If we write: 
>>> 
>>> :Alice :plays :Guitar .
>>> [] :occurrenceOf <<:Alice :plays :Guitar>> ;
>>> :stop 2021.
>>> 
>>> We added some triples (namely [] :occurrenceOf <<:Alice :plays :Guitar>> ; :stop 2021.) which made that our original triple is not true any more.
> 
> I don’t interpret it that way. Maybe we have a problem of the glass of water being half empty or haf full. The statement 
> 
>    :Alice :plays :Guitar
> 
> is, without a well defined vocabulary from which :plays is taken just an example to make a point. The point that I want to make is that statements can be refined without invalidating them. 

I agree. The plain triple on line 1 asserts the fact, and nothing added later can change this assertion. 

It never occurred to me that the truth of an annotated triple could be considered in doubt. If it is annotated, the plainly asserted triple is present, and therefore the triple is (expected to be understood as) true. 

> Considering all that I think that it is reasonable to interpret that
> 
>    :Alice :plays :Guitar
> 
> has a temporal aspect that is not even mentioned here and almost infinitely many other aspects that are also not mentioned, much less provided.
> 
> There are also aspects of common sense: interpreting the above statement as "Alice plays guitar NOW" runs counter the intuition that there usually is a gap between me making an observation, encoding it in RDF, sending the mail to a list that is archieved on the web, soemone else reading it that would make the 'now' claim rather questionable. Also an interpretation that "Alice ALWAYS plays guitar" is not viable in practice etc etc. I think you get my point: there is, for a human reader, all reason to believe that the above statement doesn’t describe some situation in full. But what we do know is that I stated an observation, namely that Alice plays guitar. And I did indeed observe her playing the guitar, that’s the truth (I swear!).

I agree, but I think that there are THREE, and not two, ways to assign a temporal aspect to an absolute triple: 

1) ALWAYS (or at least beyond the temporal interval of relevance of the dataset). This is my interpretation, for instance, of the triple ":Monalisa dc:creator :leonardoDaVinci", which is true for some interpretations of "always" (even though it was not true before  1513). 

2) NOW (or at least in the moment of the observation of reality by the author of the dataset). This would be my interpretation of the triple ":Alice :plays :Guitar" as well, agreeing with you. 

3) AT LEAST ONCE: there has been at least a moment in time in which the triple was true. This is the only interpretation I can give to the triple ":RichardBurton :marriedTo :LizTaylor", which is not true ALWAYS, and is not true NOW. 

This means that we have now three separate temporal interpretations of absolute triples and this makes me nervous because they are clearly but not totally incompatible with each other, and one must use common sense to decide which is which. 

Anther thing that makes me nervous is that it seems that the perception of the true temporal aspect differs depending on the triple itself rather than the predicates or the entities involves: 

> There is of course a responsibility to keep the semantic web reasonably tidy. Publishing ":Trump :presidentOf :USA" without any further detail and not removing that statement after the last election is kinda lame (well, let’s hope it’s only lame and not on purpose). 

In your example, ":Trump :presidentOf :USA" irks us, while ":Biden :presidentOf :USA" does not, because we implicitly assume that :presidentOf should have the NOW semantics (the ALWAYS is clearly incorrect for both, the AT LEAST ONCE is clearly correct for both), but at the same time it seems to me (YMMV) that the triple ":GeorgeWashington :presidentOf :USA" can be seen as less weird than the others, maybe because we (I?) have a different perception of the temporal aspects of facts and roles of historical characters. This is weird and puzzling.  

Similarly we can discuss the geographical/location/jurisdiction aspects of absolute triples, that can be EVERYWHERE, HERE, or AT LEAST SOMEWHERE. 

I really do not like absolute statements exactly for this reason. I really wish there were clear guidelines for these cases, and we did not rely on common sense or case-by-case recipes...

Ciao

Fabio


--

Fabio Vitali                            Tiger got to hunt, bird got to fly,
Dept. of Computer Science        Man got to sit and wonder "Why, why, why?'
Univ. of Bologna  ITALY               Tiger got to sleep, bird got to land,
phone:  +39 051 2094872              Man got to tell himself he understand.
e-mail: fabio@cs.unibo.it         Kurt Vonnegut (1922-2007), "Cat's cradle"
http://vitali.web.cs.unibo.it/

Received on Monday, 10 January 2022 14:00:11 UTC