This thread has been a very enlightening discussion. I do have several questions though.
Ρανδαλ ἔγραψε·
Yes, διάθεσις is the better term for the category. It would probably help Greek students to go directly to that term and bypass English 'voice,' they won't get to collect $200 in either case.
So Greek diathesis has two formal categories in some tenses and three formal categories in other tenses. But I don't recommend calling the morpho-syntactical categories "voices". That word is already defined in English, and it is always more difficult to erase a common, errant meaning, than to create a neologism built on a zero-meaning word. It may be simplest, and better, to say that some tenses have two categories of diathesis (whose FORMS are called ἐνεργητική and μέση ) and some tenses have three categories of diathesis (whose FORMS are called ἐνεργητική, μέση, παθητική). When a student inevitably asks, "is the παθητική like 'passive voice' in English?", the teacher can say "No, the Greek uses this category for many things that are not passive in English, like πορευθῆναι 'going away'."
This discussion has been very helpful. I've recently read and re-read Carl Conrad's papers on Greek Voice, and sections in Greek grammars on Voice. I believe that students of linguistics (who study the structures and presentations of multiple languages) will have an easier time understanding the Greek verb, than students who are only taught English grammar (or that of their native language). But I still have several areas of question.
(1) How should I gloss the term παθητική? Passive? Experiencer? Patient? Given the wide range of meaning and variation between actor/experiencer/patient I don't think the gloss 'passive' is perhaps the best English gloss for παθητική. What did the Greek grammarians intended for an English gloss?
(2) Perhaps we should say each verb has several 'dispositions' or 'presentations.' What is the correct Greek term for this?
διάθεσις is the usual Greek term. But I wonder if a 'more modern' discussion of voice would choose another word.
LSJ: διάθεσις· ---3 Gramm., force, function, τοῦ ὀνόματος δ. εἰσὶ δύο, ἐνέργεια καὶ πάθος (e.g. κριτής, κριτός) D.T.637.29; esp. of the voices of the verb, δ. εἰσὶ τρεῖς, ἐνέργεια, πάθος, μεσότης Id.638.8; δ. παθητική, μέση, A.D.Synt.210.19, 226.10; also of tense, χρονικὴ δ. ib.251.1 (s.v.l.); διαβατικὴ δ. transitive force, ib.43.18.
ἔγκλισις should not be the term.
II in Gramm.,
---1 mood of a verb, D.H.Comp.6, D.T.638.7, A.D. Synt.248.14, etc.
---2 throwing back of the accent, Id.Pron.8.7, al.; change of acute to grave accent, Id.Adv.169.23.
---3 inflexion, Simp.in Cat.65.8, Dexipp.in Cat.33.8: generally, of derivative forms, Simp.in Cat.37.11.
πρόθεσις
---IV. Gramm., preposition, Chrysipp.Stoic.2.45, D.T.634.5, D.H.Comp.2, A.D.Synt.305.24, Pron.64.5.
---2. prefixing, placing first, Id.Synt.311.1, Pron.58.16.
---3. π. καὶ πτῶσις perh.stem (or root) and ending, Phld.Po.2.18.
προβολή
---1) A putting forward, esp. of a weapon for defence,
---2) putting forth, βλαστοῦ Gp.5.25.1.
---3) putting forward of a plea or case, Hermog.Stat.4, al.
πρόσωπον - I think this is too passive a term - it is more of a term of perception than presentation.
---3 Gramm., person, D.T.638.4,A.D.Pron.3.12, etc.; γυναικεῖα π. Alex.Trall.2.
I'm sure I've missed other words. But I think that the English term 'voice' should be deleted from Greek pedagogy. (Most first year students would use φωνή for the term 'voice'.) The English term 'voice' is too tied to the English active/passive dichotomy that English students of grammar want to peg to every verb. And that just does not fit Greek verbal usage. (As a curiosity, there are languages which do not have a passive voice. I think Lithuanian is one. This lack of a 'voice' has to be problematic to our 'either/or' concept of a verb.)
3) I think we really need to look at individual verbs and how each verb relates to its subject. I was reading "A Grammar of the Greek Language" by William Eduard Jelf (1862). It can be found on Google books. Even 200 years prior, students of Greek were trying to categorize the Greek verb in more modern linguistic terms as 'agent', 'patient' 'experiencer', ktl.
(4) The study of ancient Greek voice needs to look at modern studies of voice. Is the medio-passive voice still a part of the Greek language? Is it the same now as 2000 years ago? Can I argue from Modern Greek that an ancient text means the same as the modern?
I have more questions than answers. Again, this thread has really made me think/rethink my understanding of Greek 'diathesis.'