The traditional view of the augment as a past tense marker is also more plausible from a historical point of view. An attractive etymology of the augment is that it goes back to a PIE distal deictic (first spatial and then temporal?) adverb or proclitic particles *h1e(-) “there, then,” of which relics can be also found in ἐ-κεῖνος and ἐ-χθές.And on the next page or so:
It should be noted that the augment already had lost much of its original function by Homer’s time: the fuzziness of the distributional rules shows that the occurrence of the augment is also determined by metrical factors. The distributional tendencies can therefore only be regarded as traces of the augment’s older distribution. The semantic change from Homeric to Classical Greek can be seen as a form of generalization and bleaching. The augment becomes obligatory on all secondary indicative forms and it develops semantically from a marker highlighting past time reference to a neutral past tense marker. The introduction of the augment brings Ancient Greek into alignment with the typological tendency for past tenses to be the morphologically marked category with respect to the (often morphologically unmarked) present tense (see, e.g., Östen Dahl, Tense and Aspect Systems [Oxford: Blackwell, 1985], 117). (emphasis original)<idle musing>
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