I mean, the answer is kind of simple. You edit and reprint them. If you’re the author.

I’ve had occasion this week to consult what Mounce, that most widely used Greek textbook, says about aspect.

Similarly, I also dipped into Duff. Now Duff is unfortunately a revision of Wenham which is a revision of Nunn. I’m sure some places out there are still using Wenham. I hope no one is still using Nunn! Duff’s 3rd edition from 2005 discusses Greek verbs on p66. It begins with tenses, and at least discusses aspect, saying that verbs encode both time and aspect. It lists the aspects like this:

• Present tense: process or undefined
• Future: undefined
• Imperfect: process
• Aorist: undefined

It also says that undefined is either ‘undefined’ or punctiliar in contrast to process.

I won’t hammer Duff on other issues (deponency, for one), at least today.

The perfect doesn’t appear in Duff until 16.1 (p179), he says the aspect is “completion”, which isn’t too far off, really. And he says the time is past and present, which is a little confusing I would think.

My problem with Duff is that the terminology is inconsistent, and that the presentation of aspect is muddled. Although I think Campbell is wrong about the perfect, one very helpful thing he achieved was to disentangle aspect from Aktionsart and to help people think of these separately. Punctiliar is a type of action, aktionsart, it doesn’t help us to use it for an aspect. “Undefined” is not a helpful label for an aspect, because it actually doesn’t tell you anything. The aorist tense-form is aoristic, i.e. undefined, but only in the language of Greek grammarians. In our language ‘undefined’ could be perfective or imperfective!

There are things we might disagree about, and there are things we just need to get clear. For instance, I think Duff is just wrong about the Present being ‘either’ “process or undefined”. But I think there are a number of things that have become reasonably clear in the last few years, and NT textbooks could serve us all well by revising themselves for their next reprint.

Adopt a clear terminology of, say, perfective vs. imperfective, divorce time from aspect, get rid of deponency language, and then use a clear terminology to state points of ‘position’.

Decker does this pretty well in his work, I don’t see why a revised Mounce or Duff couldn’t do likewise. If you want to say that time is encoded in verbs tense-forms, fine, just state it clearly. If you want to say that the perfect is imperfective in aspect, fine, just make it clear that that’s what your textbook is doing. Conflating categories and muddling terminology is not helping students in this field and isn’t going to set them up well for later on.