Reflections on Arabic and Semitic: Can proto-Semitic case be justified?

From a comparative linguistic perspective the question whether or not proto-Semitic had a functioning case system similar to that in Classical Arabic does not readily yield an unequivocal answer. It is generally agreed that there are Semitic languages or sub-language families for which a proto-case system is plausible, but equally, there are others where such a system did not exist. The issue is, arguably, more interesting for Arabic than for any other Semitic language, since Arabic is a language whose contemporary varieties totally lack morphological case, but whose classical variety had a case system. In this paper I reiterate arguments I have made before for the indeterminacy of knowing whether proto-Arabic had a case system, embedding it in an expanded comparative look at two Semitic languages, Amorite and Epigraphic (Old) South Arabian. As a spinoff of this comparative discussion one can contemplate ways in which the case system such as described by Sibawaih was instrumentalized out of a system which was not necessarily the system he himself described. Giving greater due to comparative linguistic arguments than is customary practice in Semitic studies opens the door to a consideration of a number of important aspects of Arabic linguistic history which have hitherto been neglected.