After having provided an answer to Draconis’ question ( Did Latin have any ergative verbs? ), I was wondering about the subtle meaning differences involved in triads like {aperit/se aperit/aperitur}, {movet/se movet/movetur}, {mutat/se mutat/mutatur}, etc. I’m basically interested in how this grammatical triad, which is mainly found with some verbs of change, was interpreted in Early & Classical Latin (comments on Late Latin are also welcome).
Beyond the particular preferences involved in different authors/registers/… and beyond the particular lexical encyclopedic-like differences (e.g., in terra movet an earthquake is involved), are there any semantic generalizations associated to the abovementioned grammatical triad {labile / reflexive / middle}? When is each of them used? Is it a case of full synonymy?
Some examples follow:
Foris aperit (Pl. Pers. 300) ‘The door is opening’.
Valvae se ipsae aperuerunt (Cic. Div. 1, 74) ‘The doors opened by themselves’.
Ecce autem commodum aperitur foris (Pl. Mil. 1198) ‘and look, at this very moment the door is opening'.
Flos numquam se aperit nisi vento spirante (Plin. Nat. 21.94.165) ‘the flower never opens unless the wind blows’).
Tum sumus incauti, studioque aperimur in ipso, / nudaque per lusus pectora nostra patent (Ov. A.A. 3 371-372) (‘…we reveal ourselves in our very zest…’).
Ubi aliud os amnis aperitur (Curt. 6,4, 7) ‘Where another mouth of the river opens’.
At first sight, there appears to be no meaningful difference between the {labile / reflexive / middle} examples above. But is this intuition correct? For example, for those all of us who speak a Romance language natively, it is not surprising that subtle differences may sometimes emerge from using the reflexive or not: e.g., cf. Spanish Juan {se murió /murió} anoche 'Juan died last night'. Apparently, the meaning of this example with or without the pronoun is the same but, on a closer look, it is not the same in all contexts: cf. ok Juan murió anoche fusilado vs. *Juan se murió anoche fusilado. Cf. also the following contrast from French: Jean (*se) rougit vs. Il vit le mouchoir se rougir soudain. NB: the star * means ungrammaticality.