What is the difference in meaning/usage between "nasciturus" and "nascendus"?

Question

Both nasciturus and nascendus seem to exist. Words ending in -turus are often described as future active participles, and words ending in -ndus as future passive participles (they are also called gerundives), but as nascor is always an intransitive verb, it doesn't seem like it could have any truly passive forms. (I think this differentiates nascendus from examples like patiendus, discussed in brianpck's answer here: How do I use gerundives of obligation for deponent verbs?)

I would guess that there is a difference in meaning something like "about to be born" vs. "needing to be born", but I don't understand the Latin participle system well enough to be sure.

Research

I found a passage in Ars by (pseudo?) Palaemon that mentions the two forms, but my Latin is not strong enough to extract any information about potential differences in meaning or usage between the two forms:

futuri temporis participia a passivis vel communibus semper in dus. nam deponens numquam habet duo futura: nec enim dicimus 'luctandus est ille' aut nascendus, sed habet unum, ut luctaturus nasciturus locuturus; licet apud veteres talia quoque communis generis reperiantur.

("De Participio", Ars [sp.], in Keilor 1868, 546.9-13, accessed via PHI Latin Texts)

I also found an interesting but not very enlightening anecdote about a poor gentleman who shared my confusion and was excoriated by a bishop (The Downside Review, p. 228). Basically, all this does is confirm my understanding that both nasciturus and nascendus are valid forms. The bishop brings up the “ad homines nascendos vim hujus numeri (septenarii) pertinere ait” quote that is also mentioned in the Lewis and Short entry for nascor; L&S say that it can be translated as "to the formation of man in the womb".

Searching for the text of this passage also led me to a section of Roby (1875; A Grammar of the Latin Language from Plautus to Suetonius, Part II) that discusses this use of the gerundive. This was more helpful. Roby says that there are "very few" exceptions to the rule that the gerundive is passive, and therefore not used for intransitive verbs; he lists some examples and says "three of them are from Varro; they are all expressions of the same nature and all from verbs in -sc-" (p. lxx).

The examples seem to go against my guess that the gerundive would have a sense of obligation in this context; Roby translates them with phrases like "of the X-ing of Y". After reading Roby, I have the impression that even though nascendus isn't 'wrong' per se, there wouldn't be very many situations where I should use it. Does anybody have any further advice or information about the use of these two participial forms?

Answer 1

In his Corso elementare di lingua latina ("Elementary Latin course", 1844), Vincenzo De Angelis deals with this in Volume 1, p. 191:

Se il verbo indica azione vi sarà il passivo, come amo ed amor... e perciò amans ed amatus-amaturus ed amandus. Ma ove indicasse uno stato intransitivo, nè il verbo vi sarà con questo doppio valore, e forma; nè participi attivi e passivi potranno darsì: ma di uno stato assoluto un presente può aversi ed un futuro nascens o natus, nasciturus o nascendus. Il perché mancando qui diverso valore, ogni differenza tra nascens e natus, tra nasciturus e nascendus si risolve nel tempo, ove le due coppie fossero in uso;

"If the verb indicates an action there will be a passive form, like amo and amor... whence amans, amatus - amaturus and amandus. But for an intransitive one, neither will it have such double value and form, nor will active and passive participles be possible: however a present form and a future form of an absolute construction are possible, [e.g.] nascens or natus, nasciturus or nascendus. Since there is no difference in value, any difference between nascens and natus, nasciturus and nascendus, [and the like] resides in the time [of "action"], where the two pairs are both in use;"

Being a dated work, the original wording is a bit convoluted (in my eyes, at least) - I tried my best to make it clearer, but any improvement in the translation is welcome. Anyway, it seems De Angelis is suggesting that for pairs like nasciturus/nascendus, only one form really means "about to be born" (nascendus in this case, as your ad homines nascendos... quote would confirm) whereas the other one would be more distant in the future, "that will be born".

For what it's worth, only nasciturus made it into Italian as nascituro (though perhaps this also has to do with nascendo being the gerund present of nascere).

I think it's interesting to draw a parallel with moriturus / moriendus, quoting Leo De Lacy here:

There are some verbs which have no passive participle in -dus. Some as vapulo, and other neuter passives which, having no passive form whatever, cannot have that participle, and yet the gerund occurs with est [...]. It is very significant and conclusive on this point that, of the deponent morior, the future participle in use is moriturus, never moriendus (instead of which the verbal adjective moribundus is very frequently found).

Answer 2

I think that the meanings attributed by sumelic to nasciturus and nascendus ("about to be born" and "needing to be born", respectively) are more or less appropriate (NB: the modal meaning "needing" is not present in all gerundives. Rather the "conditio sine qua non" for gerundives seems to be that their argument must be a Patient/Theme). The form nasciturus is not problematic. So I guess that the question has to do with the apparently somewhat unexpected form nascendus. In this sense I consider sumelic's excerpt above from Roby's (1875) grammar quite interesting and, in fact, crucial to understand the problem (why nascendus is a possible form). So one would like to know WHY the apparently unexpected gerundive forms of the nascendus-type commented on by Roby can be found with intransitive -sc- verbs. It would seem that gerundives can only be obtained from verbs that can be passivized (cf. Roby's traditional claim that gerundives are passive forms).

Well, I think that part of the answer can have to do with the fact that the class of intransitive -sc- verbs is formed by unaccusative verbs, namely, those intransitive verbs that, semantically speaking, have a Theme/Patient argument, which, syntactically speaking, has been claimed to act as a "direct internal argument". In the linguistic literature, there are two types of direct internal arguments: direct objects of transitive verbs and subjects of unaccusative verbs. In fact, according to many formal syntacticians, the (derived) subject of unaccusatives is generated as a direct object. So perhaps the existence of this parallelism (the one between direct objects of transitives and subjects of unaccusatives) makes Roby's point on -sc- verbs less unexpected or at least not so surprising.

The previous explanation has a non-trivial problem: intransitive -sc- verbs form a very important subclass of unaccusative verbs (probably, the most productive one), but what about unaccusatives like mori? As pointed out by Vincenzo Oliva, moriendus is not a possible form. Well, perhaps a "blocking" phenomenon is relevant here (https://en.wikipedia.org/wiki/Blocking_(linguistics)): the existence of moribundus can be said to prevent the formation of moriendus.

As for sumelic's final impression that "there wouldn't be very many situations where one should use nascendus", please take a look at the examples below. I've just consulted Pinkster's (2015) Oxford Latin Syntax and he, basically, gives examples that confirm Roby's insightful point on -sc- verbs without providing any explanation of why this class of verbs is the one affected. Indeed, the topic is complex... Here is the list of examples given by Pinkster on page 296:

Cui testis aestas et hiems, quod in altera aer ardet et spica aret, in altera natura ad nascenda cum imbre et frigore luctare non volt . . . (Var. L 5.61)

Seclum spatium annorum centum vocarunt, dictum a sene, quod longissimum spatium senescendorum hominum id putarunt. (Var. L. 6.11)

Genethliaci quidam scripserunt, inquit (Varro) esse in renascendis hominibus quam appellant 'palliggenesían' Graeci. (Varro ap. August. Civ. 22.28)

AEDIS·FLORAE QUAE·REBUS FLORESCENDIS PRAEEST DEDICATA EST PROPTER STERILITATEM·FRUGUM (CIL I1, p. 236.28 (Fasti Praenestini, between 6 and 9 AD))

Semel haec mihi videnda sint, an saepe nascendum? (Sen. Ep. 65.20)

... in moribus inolescendis magnam fere partem ingenium altricis et natura lactis tenet... (Gell. 12.1.20)

...exque eo genitos vel nascendos filios [‘sons yet to be born’!] similiter paternae condicioni subiacere praecipimus. (Cod. Just. 5.27.4)

By the way, when discussing the nature of gerundive, some lines above Pinkster (2015: 295) concludes: "It seems, then, that interpretation of a gerundive as passive or (more frequently) active depends on contextual and sometimes on extralinguistic information" (bold/emphasis mine). Well, perhaps he is right or perhaps he is not... For a more grammatical perspective, see the following work by Miller:

Miller, D. Gary. (2000). "Gerund and gerundive in Latin". Diachronica 17 (2): 293–349. DOI: 10.1075/dia.17.2.03mil

Well, as you can see, this topic of Latin grammar is very complex. Perhaps some of you would like to write some work (paper, doctoral dissertation, ...) on gerundives. If so, please keep me posted (by the way, I don't know if comments like this one are allowed in this site. If they are not appropriate, please, editors, feel free to delete it. Thanks!).