Choosing conjunctive tenses in a clause subordinate to a subordinate clause

Question

I will phrase my question through an example. Consider this sentence in English:

I do not know whether you wrote where you are.

This has one governing clause ("I do not know") and two indirect questions, first subordinate to the governing clause, the second subordinate the first one. In Latin the predicate of a subordinate conjunctive clause follows consecutio temporum (sequence of tenses), and the correct tense depends on that of the governing clause.

The first question is governed by the present tense "I know" (scio) and describes an event before that of the governing clause, so I should use the perfect tense for "wrote" (scripseris). But which of the verbs scio and scripseris is considered to govern the second question? If scio, I should use the present tense for "are" (sis). If scripseris, then imperfect (esses). I am not sure, so I am left with two possible translations:

Nescio, an scripseris necne, ubi sis.
Nescio, an scripseris necne, ubi esses.

Are both of these grammatical and good style in classical Latin? If yes, is there a difference between the two? (The starting point is the meaning of the opening example sentence in English.)

In general, if a conjunctive clause is subordinate to another conjunctive clause, what determines the tense in the "lowest" clause? Does it only depends on the tense of the nearest dominant clause or that of the clause at the top of the hierarchy? I would prefer to see examples from classical literature where such nested clauses appear.

Clauses subordinate to a nominal form were treated here, but the source used there does not discuss the present question.

Answer 1

This is what Adolf V. Streng (Latinan kielioppi, 5th edition, 1936) says in §161.2:

Finnish: Toisen tahi kolmannen asteen konjunktiivinen sivulause mukautuu predikaattinsa tempuksen puolesta sitä lähinnä hallitsevan sivulauseen mukaan.

Free translation: A conjunctive subordinate clause of second or third order adapts to the closest governing clause with respect to its tense.

Examples (no citation given):

1. Nescio, quid causae fuerit, cur nullas ad me litteras dares.
2. Quid tibi placeat, pergratum erit, si ad me scripseris.
3. Gratias ago Pisoni, qui non, quid efficere posset in re publica, cogitavit, sed quid ipse facere deberet.

By higher order subordinate clauses he means clauses subordinate to a subordinate clause — exactly what the original post was about.

If Streng is to be believed, the tense of a subordinate clause depends on the immediate governing clause according to consecutio temporum. This also answers the example situation:

Wrong: Nescio, an scripseris necne, ubi sis.
Right: Nescio, an scripseris necne, ubi esses.

Answer 2

If we have a subordinate clause depending on superordinate conjunctive clause, we must consider the tense of the conjunctive:

(A) present or perfect "logic" (assimilable to a present), it should be used the tenses prescripted by the consecutio temporum of the primary times, like in Sen. ep. 32,1:

sic vive tamquam quid facias auditurus sim

(B) conjunctive imperfect, pluperfect or perfect "past" (optative or concessive), and then we should use the tenses prescripted by the consecutio temporum of the historical times, like in Cic. Att. 1,5,2:

testis erit tibi ipsa, quantae mihi curae fuerit, ut Quinti fratris animus in eam esset is, qui esse deberet

You could find information on the tenses prescripted by the consecutio temporum of the subordinate clauses in almost all latin syntax reference works, for example:

• E. Woodcock, A New Latin Syntax, Bristol 1959, pp. 98-108;
• A. Ernout - F. Thomas, Syntaxe latine, Paris 1964, pp. 547-554;
• J.B. Hofmann - A. Szantyr, Lateinische Syntax und Stilistik, München 1972, pp- 393-402;
• A. Traina - T. Bertotti, Sintassi normativa della lingua latina, Bologna 1985, pp. 345-354.

Answer 3

If yes, is there a difference between the two?

The answers here seem to imply that the difference is that one is grammatical and the other isn't, without explaining why. Instead of just saying "this is wrong, this is right", we can try and gain a better insight by taking a speaker's point of view. This will allow us to arrive at a functional explanation, which is that the two sentences in your example (with my corrections) mean two different things:

• Nesciō utrum scrīpserīs necne, (aut) ubi sīs "I don't know whether you wrote to me or not, or where you are [at the moment]" - here the two questions both depend on nesciō;
• Nesciō utrum scrīpserīs necne, ubi essēs "I don't know whether you wrote to me or not(,) where you would have been" - this is difficult to parse in either language due to the placement of necne "or not", since ubi essēs could be understood as coordination (above) or subordination (below). A better phrasing is:
• Nesciō utrum scrīpserīs ubi essēs necne "I don't know whether you wrote to me regarding your whereabouts or you didn't".

As you can see, the tense of the dependent clause serves to determine which main verb it's subordinate to - the present nesciō or the past scrīpserīs - yielding different interpretations.

I replaced an with utrum because an normally introduces the second and less immediately apparent option, thus annōn = rhetorical necne. Besides this, nesciŏ·an also functions as an adverbial meaning "perhaps, I'd say".

Notice that the often confusing distinction between an and aut serves a parallel purpose: nesciō Gāius an Jūlius "I don't know whether it was Gaius or Julius" is the disjunctive, exclusive "or", nesciō Gāius aut Jūlius "I don't know, it was Gaius or Julius" is the conjunctive, inclusive "or". In the latter case Gaius and Julius could be the same person, for which vel is the canonical choice of conjunction.