(*E.g., http://www.artsci.wustl.edu/~cwconrad/d ... 11_002.pdf; see also Michael Palmer's discussion http://greek-language.com/grammar/21.html)
Two examples:
(1) γινώσκω: Every Future Middle occurrence of γινώσκω in the NT is subject-focused (which is to be expected with a verb of cognition) or, according to the traditional model, deponent. Every Future Passive occurrence of γινώσκω in the NT is passive in meaning. The same pattern seems to hold for the LXX as well. Here is the example my friend sent me:
Mark 4:13 Καὶ λέγει αὐτοῖς• οὐκ οἴδατε τὴν παραβολὴν ταύτην, καὶ πῶς πάσας τὰς παραβολὰς γνώσεσθε;
Matthew 10:26 Μὴ οὖν φοβηθῆτε αὐτούς• * οὐδὲν γάρ ἐστιν κεκαλυμμένον ὃ οὐκ ἀποκαλυφθήσεται καὶ κρυπτὸν ὃ οὐ γνωσθήσεται.
(2) The same pattern appears with ἀκούω:
Acts 17:32 Ἀκούσαντες δὲ ἀνάστασιν νεκρῶν οἱ μὲν ἐχλεύαζον, οἱ δὲ εἶπαν• ἀκουσόμεθά σου περὶ τούτου καὶ πάλιν.
Luke 12:3 ἀνθ᾽ ὧν ὅσα ἐν τῇ σκοτίᾳ εἴπατε ἐν τῷ φωτὶ ἀκουσθήσεται, καὶ ὃ πρὸς τὸ οὖς ἐλαλήσατε ἐν τοῖς ταμείοις κηρυχθήσεται ἐπὶ τῶν δωμάτων.
My question: Even if we grant that aorist and future middle forms are subject-focused rather than deponent, is there (sometimes?) a semantic difference that maps onto the distinction between middle and passive forms when both forms occur in the same verb in the aorist or future?
I skimmed Rutger Allan's dissertation quickly and was surprised to see that he argues for a semantic distinction between sigmatic middle aorists (= 1st Aorist Middle forms) and θ(η) Aorists (Aorist Passive forms):
If Allan is correct--and I haven't noticed discussion of this aspect of his argument on this forum--the system is way more complicated than I had imagined, and I am left wondering (again) how best to explain Greek voice to 1st year Greek students. Allan is, of course, describing Classical Greek, but his argument appears to explain the two examples above. Is the answer that we must know each verb or can we generalize in the cases when both middle and passive forms appear in the aorist or future?"Sigmatic middle aorists with passive meaning do not exist in historical Greek" (111 n. 269).
(On the other hand, "root and thematic aorists" (e.g. 2nd aorist middle forms) do occur with both middle and passive meanings (128; 131 n. 309).
"[T]he passive aorist marks that the subject is, or is at least similar to, a prototypical patient. By contrast, the subject of the sigmatic middle aorist is similar to a prototypical agent." (186)
"The contrast between the middle and the passive future is to be explained differently for each individual verb." (150)