Misreading "mood": the subjunctive

Sībawayhi has no explicit term corresponding to our "mood" (or "modality"). Does he have the concept, even if only implicitly? I'm not sure; after all, even contemporary linguistics doesn't quite know what the concept is, precisely. He clearly had a notion that seems to correspond closely with our notion of "indicative" - but did he think of that as a mood? Usually we treat mood/modality as expressing (in some manner) speaker's attitude towards ... something. It's not at all clear (to me) that Sībawayhi thought in such terms with respect to the interpretation of grammatical form.

But I'm pretty sure he had no concept corresponding to our "subjunctive". Usually (universally?) Western authors treat the imperfect verb with "accusative" (نصب) inflection (i.e. /a/ inflection as in يَذْهَبَ yaðhaba) as the subjunctive marker. Hence أَنْ يَذْهَبَ خَيْرٌ لَهُ ˀan yaðhaba xayrun la-hu is glossed as something like "that he go [subjunctive] is better/best for him".

But that cannot be right. The most obvious problem is that the same inflection is used for the negative future indicative: لَنْ يَذْهَبَ lan yaðhaba "he will not go". So if أَنْ يَذْهَبَ ˀan yaðhaba is to be treated as the subjunctive, it cannot be solely because of the inflection. Which means that the a-inflection alone cannot function as a mood marker. If there is some modality involved, it must be due to the combination of the عَامِل ʕāmil "elaborator" that "works" the inflection in the verb - in this case, either أَنْ or لَنْ (or كَيْ see ch. 233 هٰذَا بَاْبُ إِعْرَاْبِ الْأَفْعَاْلِ الْمُضَاْرِعَةِ لِلْأَسْمَاْء) Note that unlike the subjunctive in e.g. Latin, the a-inflection (for verbs) only ever occurs when preceded by one of these three ناصِب "particles".

But even if we agree that the semantics of the verbal a-inflection is dependent on a preceding particle, the question remains: is e.g. أَنْ يَذْهَبَ properly characterized as expressing "subjunctive mood"? I don't think so. Or more precisely: I don't think that Sībawayhi thought so. And what about all the other cases he treats in chapters 233-244?

He does not treat "the meaning of نصب for the verb" as a topic worth addressing in a dedicated chapter. (That in itself is very revealing.)

He does however handle it indirectly. The topic of Chapter 237 is إِذَنْ which may be followed by a verb with either u-inflection ("indicative"?) or a-inflection. It's a fairly complex chapter. In the course of his discussion he gives a fairly clear (albeit not entirely unambiguous) account of the meaning of أَنْ and إذَنْ with a-inflected verbs:

Sorry I don't have a complete translation yet, but the key point is that he explicitly says (segs 87-88) that the verb after أَنْ and كَيْ has not occurred (غَيْرُ واقع) and is not present tense (not a فِعْل ثابت "steady/continuing action" at the time of your speaking في حال حديثك) . He then adds two examples of a-inflection after إذَنْ indicating that the action will occur (سَيقَعُ , indicative) or that the action is ongoing (the subject of the action is في حال ضربٍ لَمْ ينقطِعْ "in a state of striking that has not cut off").

I don't see any notion of "subjunctive mood" in this passage. Sībawayhi seems to be thinking entirely in terms of tense and aspect. The difference between إذنْ أظُنُّكَ and إذَنْ أظُنَّكَ is the difference between present state and future occurrence or state.

On the other hand, it would not be completely outlandish to interpret e.g. seg 90  تُرِيْدُ أَنْ تُخْبِرَهُ أَنَّ ظَنَّكَ سَيَقَعُ  turīdu ˀan tuxbira ˀanna ẓannaka sa-yaqaʕu as saying something about speaker's attitude or mood: "you intend to inform that your opining will occur" isn't all that far removed from saying that that's your mood. He uses أراد ˀarāda "he intended" frequently, in a variety of contexts, and "speaker's attitude" is arguably a kind of intentionality in the technical philosophical sense of "aboutness". Personally, I think that's a bit of a stretch. I think he was talking about what speakers want to say, not their attitudes toward what they say. Reading "mood" into أنَّ ظَنَّكَ سَيَقَعُ feels a little too procrustean.

I think the lesson we should take is just that, even if the verbal a-inflection may express something like the subjunctive mood in some circumstances, it would be a mistake to think that an invariant of constructions like أنْ يَفْعَلَ . In other words, it is a mistake to think that "subjunctive mood" was, for Sībawayhi, a basic or fundamental feature of verbs.