# a priori, a posteriori



## M Mira

Why do they end in -i? Does that mean

A) "ab" can take dative arguments
B) Ablative singular ending of third declension nouns (or maybe just comparatives) can be either -e or -i
C) This is an ancient formation that's preserved and fossilized, hence it doesn't necessarily follow later Classical Latin grammar.
D) This appeared in late Vulgar Latin when declension was heavily eroded, much like why we have "Deus lo vult" instead of "Deus illud vult".

Or did I miss something?


----------



## Scholiast

salue M Mira, and a hearty welcome to the Latin Forum.

Sorry not to be able to offer chapter and verse from A&G right now (I am wrestling with the idiosyncrasies of a new computer), but for mysterious reasons, 3rd-declension adjectives take the ending _-i_ in the ablative singular, except when they are participles in ablative absolute constructions.

This annoyingly perverse behaviour on the part of adjectives and participles bothered me already as a teenager when I was learning my basic Latin, and I still don't fully understand why these things have to be so recalcitrant to logic or sense.

Σ


----------



## M Mira

Scholiast said:


> salue M Mira, and a hearty welcome to the Latin Forum.
> 
> Sorry not to be able to offer chapter and verse from A&G right now (I am wrestling with the idiosyncrasies of a new computer), but for mysterious reasons, 3rd-declension adjectives take the ending _-i_ in the ablative singular, except when they are participles in ablative absolute constructions.
> 
> This annoyingly perverse behaviour on the part of adjectives and participles bothered me already as a teenager when I was learning my basic Latin, and I still don't fully understand why these things have to be so recalcitrant to logic or sense.
> 
> Σ


(Sorry for the late response, I kinda forgot about the thread as no alerts popped up.)

Why doesn't Wheelock or Wiktionary mention this if the phenomenon is rather widespread and found its way into English? Is there some reason not to?


----------



## Scholiast

Salve M Mira

I have found the appropriate sections of A&G (online through Perseus): §§114 _et seq._, especially §121. The position is rather more complicated and irrational than the rule-of-thumb I offered in my previous post (e.g. comparative adjectives usually have _-e_ in the abl. sing.), but there appears to be no consistent rule (I'll be only too glad to be corrected on this by other Foreasters more knowledgeable than I).

I confess I do not understand what you mean by "...and found its way into English", but I bet there is something somewhere in Wheelock on this. I would not trust Wiktionary, either for accuracy or completeness.

I hope this helps.

Σ


----------



## Xavier61

M Mira said:


> Why do they end in -i? Does that mean
> 
> A) "ab" can take dative arguments
> B) Ablative singular ending of third declension nouns (or maybe just comparatives) can be either -e or -i
> C) This is an ancient formation that's preserved and fossilized, hence it doesn't necessarily follow later Classical Latin grammar.
> D) This appeared in late Vulgar Latin when declension was heavily eroded, much like why we have "Deus lo vult" instead of "Deus illud vult".
> 
> Or did I miss something?


E) Medieval philosophers were not good latinists
The right usage in Classical Latin is "a posterior*e *parte versus hexametri".


----------



## Xavier61

Scholiast said:


> Salve M Mira
> 
> I have found the appropriate sections of A&G (online through Perseus): §§114 _et seq._, especially §121. The position is rather more complicated and irrational than the rule-of-thumb I offered in my previous post (e.g. comparative adjectives usually have _-e_ in the abl. sing.), but there appears to be no consistent rule (I'll be only too glad to be corrected on this by other Foreasters more knowledgeable than I).


The basic rule is that 3rd declension adjectives can be either of consonantal or -i stem. Comparatives are of consonantal stem, so they always make abl. sng. in -e. Present participles are of -i stem, so they normally take -i, but in ablativus absolutus in Classical Latin, they take -e, and also when used as nouns (if memory does not fail me).


----------



## Scholiast

salvete de novo



Xavier61 said:


> Comparatives are of consonantal stem, so they always make abl. sng. in -e



Not "always": see A&G § 120. And this does not account for consonantal-stem adjectives forming their abl. sing.s in_ -ī_, which normally they do.

But see Xavier61's explanation in the parallel discussion in the Etymology and Linguistics Forum, explaining the merger of locative and instrumental cases, which makes some sense, without explaining every variation.

Σ


----------



## Scholiast

Xavier61 said:


> Medieval philosophers were not good latinists
> The right usage in Classical Latin is "a posterior*e *parte versus hexametri".



Mediaeval philosophers and logicians were better Latinists than most of us—they were used to speaking Latin, not just reading it. But they were not academic philologists, and perhaps we may assume that by the time the terms _a priori_ and _a posteriori_ came to be coined, the general "rule" had become fixed by those who preserved and transmitted instruction in the language that 3rd-declension ablative singular adjectives end in -_ī_, irrespective of stem.

Which must give textual critics food for thought, as the majority of the MSS on which our knowledge of classical texts depends, issue from the XIth-XIVth centuries.

Σ


----------



## Xavier61

Scholiast said:


> salvete de novo
> Not "always": see A&G § 120. And this does not account for consonantal-stem adjectives forming their abl. sing.s in_ -ī_, which normally they do.
> Σ


I would like to see some instances of ab. sg. in -i for comparatives  in Classical Latin.
About consonantal-stem adjectives forming their abl. sing. in -ī, that was a consecuence of the merger, still incomplete. There is no regularity: anceps, praeceps take -i, but particeps, princeps take -e.


----------



## Xavier61

It has already been discussed here:
"In other cases, habits of the Merovingian era were so entrenched that they could not be uprooted. Endings in -i and -e of the third declension were confused and came to be no longer distinguished. Alcuin writes a dative in -e in the line vestrae pietate remisi and he is deceived by the form of the ablative when he writes cum suo abbate . . . et successori. An -i ending in ablatives of comparatives became common in the Middle Ages. Schoolmasters even formed the expressions a priori, a posteriori, which survive in the academic style of the modern languages."
A fortiori / a forteriori


----------

