Position of 'aber' in sentence

Question

There are related questions: Aber, position in a sentence, Position of “aber” after first element of sentence, Position der Konjuktion "aber". I've read these, the Wiktionary entries (English and German), and the DWDS entry, but I'm still a bit confused. In particular I'm puzzled by this Usage note in Wiktionary:

"Unlike most other conjunctions, aber doesn't need to be the first word of a clause and can thereby emphasize the preceding word(s): Ich bin dafür, er aber lehnt es ab. — “I’m in favour, but he has rejected it.” In such a construction, aber can be considered an adverb, though the usual interpretation is that it is still a conjunction."

This confirms some of the information given in the SE posts, but it doesn't explain a sentence I recently came across:

"Kein Grund sich zu entschuldigen, aber es ist wirklich schön, dass du es getan hast."
"Das war aber deine Schuld!"

Context: The two people have just collided in a hallway; the first person thinks she's owed an apology and sarcastically thanks the second person for it even though he didn't offer one. The second person is annoyed by this and says it was her fault in the first place. (My transcription probably isn't completely accurate. The emphasis is mine.)

To summarize what I think is happening:

1. When "aber" begins a clause it functions as a conjunction and can be translated as "but".
2. When following another word it functions as an adverb as described in the usage note. I think a more natural translation of the Wikipedia example would be "I’m in favour; he, however, has rejected it." For some reason this meaning is still listed under "conjuntion" in dictionaries.
3. When following the verb, it functions as a modal particle and conveys "to the contrary". So "It was (to the contrary) your fault!" There are other meanings of "aber" as a modal particle, but they don't seem to fit here.

So my problem with the usage note is that it covers 2 but not 3. The speaker was not trying to single out "war", so at best the note is incomplete. I think 3 is confirmed by many of these DWDS search results. Is my summary correct and should the note be amended? Or have I misunderstood something?

Answer 1

I think the reason for your puzzlement is the Derman sentence structure, which offers more freedom than English.

Emphasis in a German sentence can be conveyed by putting something in front (or at the end) of it. From your examples:

Ich bin dafür, aber er lehnt es ab.
Ich bin dafür, er aber lehnt es ab.

It is possible to do the same with other parts of the sentence, here a Verb:

Viele können gehen, aber nur wenige schreiten.
Viele können gehen, schreiten aber nur wenige.

In both cases the basic meaning is the same: a contrast is described (between the "normal" case and an "extraordinary" one). In the first sentence the contrast is between what "I" and "he" does/thinks, in the second it is the (ability for an) activity, which sets apart a majority and a minority.

In both cases the only reason why the specific word is moved up front is to emphasize what this contrast actually is - in the first sentence the person, in the second the activity.

The "Adverb" theory IMHO doesn't really explain anything. In German Adverb is everything we are not sure where else it should go. I suppose if you really really want you could call "aber" in these cases a "mood particle" and in fact it can sometimes be replaced by "jedoch", "im Gegensatz dazu" and similar constructions, but I think it still serves the function of a conjunction, even though it is not in first place in the relative sentence.

Kein Grund sich zu entschuldigen, aber es ist wirklich schön, dass du es getan hast.

Now, first off, this is not a sentence, it misses some parts. It could be:

Es gibt keinen Grund sich [...]

but spoken language often uses such (colloquial) phrases to accelerate exchanges. Still, this means the part-sentence is not grammatical anyway and hence (further) grammatical analysis is futile.

The second sentence:

Das war aber deine Schuld!

is grammatical, but it could also be written:

Aber das war deine Schuld!

Most would call this an Adverb, but I still think "mood particle" fits better. It contrasts one fact (it was ones, As, fault) with a (hypothetical) fact (it was the others, Bs, fault), which B distilled out of the first sentence. The hidden message of course - B got that right - was that A indeed was the one at fault and by - sarcastically - thanking him for the not-happening apology was a way to express that. So, it describes rather a stance B takes to what he says (about: "I think you are wrong, but I'll answer anyway") than transporting a meaning of its own.