[sc34wg3] The Newcomb "howl" was: Re: New TMCL slides

[Patrick Durusau]

Greetings!

I will try to briefly answer what I think is at the core of Steve's "howl."

And for the record, Steve is right that I thought he was going to howl 
about something entirely different.

The clearest part of the "howl" reads:

> It has to do with whether it can ever be true that two different 
> association types can have a role type (reified as a single topic) in 
> common. For me, it's obvious that that situation cannot occur, at 
> least not without violating the one-subject-per-topic rule. When the 
> syntax of a topic map claims that it is happening, something is 
> seriously wrong. 
Steve concedes that due to granularity of subject resolution I could 
have a subject that encompasses what others see as two role types, which 
may cause difficulties for some uses of a topic map but after all, that 
is an author's choice.

What Steve contends is that once having chosen a subject for a role in 
an association (which reflects the author's choice in terms of subject 
resolution/granularity), that another association in the same topic map 
cannot have that same role.

What I think Steve is missing is that his position *assumes* the very 
condition that it seeks to require. That is to say that when Steve says 
"role," it has already been assumed that such a role can only appear in 
one association. It may be true that some roles cannot sensibly appear 
in multiple associations, such as Steve's rather clever example of the 
Romeo/Juliet and Tristan/Isolde.

But, that does not mean that it would be a sensible rule to say that a 
role can *never* appear in more than one association.

For example, in Louisiana law, not so terribly long ago (I don't know if 
this is still valid law), the husband of the mother of a child was 
presumed to be the father. Think about that for a moment. Note that 
biological fatherhood isn't at issue but legal fatherhood is.  This was 
not a rebuttable presumption in all but a few cases.  But, it was 
possible to obtain support from the *actual* father of the child, 
without making the child a "bastard" (a legal term in Louisiana law).

So, we could have husband role (legal) - mother role - child role, and 
father role (biological) - mother role - child role, where the mother 
and child roles participate in two different associations.

I don't think that many people would say that the mother and child roles 
in those two associations are different. That is to say, they meet the 
test of "one subject per proxy" and yet as roles they appear in more 
than one association. (Note that this isn't an analytical issue. The law 
of Louisiana defines the subjects in these associations. That we might 
model the subjects differently, for what seem to us to be good reasons, 
isn't controlling. For topic maps in legal systems, the subjects as 
defined by others are what topics represent.)

My conclusion is that roles *can* appear in more than one association 
and still meet the "one subject per proxy" test. That not *all* roles 
can do so is interesting but should not lead to the rule Steve advocates.

Hope everyone is having a great weekend!

Patrick

-- 
Patrick Durusau
patrick at durusau.net
Chair, V1 - US TAG to JTC 1/SC 34
Convener, JTC 1/SC 34/WG 3 (Topic Maps)
Editor, OpenDocument Format TC (OASIS), Project Editor ISO/IEC 26300
Co-Editor, ISO/IEC 13250-1, 13250-5 (Topic Maps)