[cap-talk] "Composite", was "Same" key

[David Hopwood]

Charles Landau wrote:
> At 4:45 AM +0000 2/16/07, David Hopwood wrote:
> 
>>At risk of repeating myself, analysing an object as a composite/abstraction
>>is useful because, for a large proportion of uses, the client neither knows
>>nor cares whether the object depends on additional hidden objects. To require
>>that there not be hidden objects would be an overspecification.
> 
> That is exactly why there should be a term for "a set of one or more 
> related atomic objects".

Yes: "abstraction". But Jonathan claims that is too general. So, unless
someone wants to propose another alternative, we have only the following
choices:

 - use "composite", and accept that the special case of a single object is
   not motivated by the everyday meaning and will have to be learnt.

 - use "abstraction", and accept that it is a more general word than we'd like.

 - use "object", and accept that this is inconsistent with the majority of
   current and historical usage in object-based systems, going back to 1965.

To me, consistency of terms within a given technical field trumps consistency
with everyday meanings, every time.

> My dictionary says a "composite" is "a thing made up of several 
> parts". I'm sorry, "composite" just doesn't work for "one or more 
> parts". You really seem to be following Lewis Carroll here: `When I 
> use a word,' Humpty Dumpty said, in rather a scornful tone, `it means 
> just what I choose it to mean -- neither more nor less.'

Carroll wasn't making such a simplistic point as to say that technical
definitions should always match everyday usage. He was a mathematician,
and knew very well that some arbitrariness in terms is unavoidable. The
knowing self-criticism of precisely the kind of formalism that he would
have practiced as a mathematician is half the joke of that story (and others
in "Through the Looking Glass" -- my favourite is the song about sitting
on a gate).

Terms should be, as far as possible, *motivated* by common usage in order
to be easier to learn; that doesn't mean that there won't be special cases
that are less well-motivated. In this particular case, as in many others,
we cannot choose a set of terms that are entirely free of flaws; we have
to pick the one with the fewest or least important flaws.

-- 
David Hopwood <david.nospam.hopwood at blueyonder.co.uk>