En réponse à Mark J. Reed :


>JC> but "wherefore?" asks for the final cause: the purpose or justification.
>
>Hm.  That could map onto the distinction implied by Okaikiar morphology.
>
>To elaborate: Okaikiar has a set of three related cases representing origin,
>point, and destination of motion: ablative, locative, allative.  In
>something of a logical stretch, I used the same morpohological
>relationship shared by those three cases for the nominative, accusative,
>and dative, mapping nominative to ablative (the subject of the action
>being where it originates), the dative to the allative (the beneficiary
>or recipient of the action being its "destination"), and the accusative
>to the locative (by default, but there's also an argument to be made
>that the action is taking place at the point of intersection with the
>object).

That's not so much of a stretch, since I had the same idea when I made 
Moten. Moten has only three cases: nominative, accusative and genitive. 
Those cases have three domains of use:
- standard: the use their names describe,
- spatial: nominative becomes locative, accusative becomes allative (Latin 
has the same), genitive because delative (what you call ablative. Also not 
too much of a stretch).
- temporal: nominative indicates moment, accusative indicates duration, and 
genitive indicates frequency.
If ambiguity can arise, Moten has two prefixes which, when used with a 
specific case, indicate that this case has the spatial or temporal meaning.

>Extending the analogy further, one can envision a three-way relationship
>between the motive behind an action (analogous to ablative/nominative),
>the goal of the action (analogous to allative/dative), and the means
>used to accomplish the action (the instrumental case, here analogous to
>locative/accusative).  But the distinction between motive and goal is
>kind of fuzzy, so I lumped them together into the "causative", using the
>"motive" ending type.
>
>Assuming I did adopt a distinction here, the next question would be what
>to call the cases.  They can't both be "causative", and it's not clear
>that that's a good name for either when the other exists.  Perhaps a "motive"
>case and an "objective" case, although the latter unfortunately
>conflicts with the term for the English accusative-and-then-some case.

In my Azak, I have a causative case for the cause of an action (answer to 
the question "why") and a case called "final" (not my invention, I saw it 
elsewhere. But it was so long ago that I don't remember where it was :(( ) 
for the goal of the action (answer to the question "what for"). I never 
found they were close enough to share a single case. On the contrary, they 
feel rather opposite to me...

Christophe Grandsire.

http://rainbow.conlang.free.fr

You need a straight mind to invent a twisted conlang.