C. S. Bartholomew wrote:A.Ag 429ff the article demonstrative and/or substantive
τὰ μὲν κατ’ οἴκους ἐφ’ ἑστίας ἄχη
τάδ’ ἐστὶ καὶ τῶνδ’ ὑπερβατώτερα.
τὸ πᾶν δ’ ἀφ’ Ἕλλανος αἴας συνορμένοις
δόμων ἑκάστου πρέπει.
Some samples of Aeschylus use of articles and demonstratives. I wonder what the difference is between τὰ ... ἄχη and τὸ πᾶν? τὰ with ἄχη indicates that ἄχη is minimally “hearer old” information. In fact it is not only hearer old but also discourse old. In other words τὰ ... ἄχη is not only presumed to be an active part of the audiences cognitive framework, it is also a recently active part of the discourse itself. This distinction is an important one. See R. A. Hoyle SIL 2008.
The meta-language used for the article in the reference grammars is somewhat confusing. In the lyric portions of Attic Tragedy the article is used in a manner also found in Homer. I think Paul was making note of this on several occasions. I’m somewhat confused on the subject of demonstrative use of the article. Smyth #1100 states that the demonstrative article can be either substantive or adjectival. Cooper (v3 p2198, 18.104.22.168) goes on and on about the substantive use of the article. He uses the expression so often that it becomes almost impossible to figure out what he means by it. The article can be used to make some constituent function as a substantive. But that is NOT what Smyth or Cooper have in mind when the refer to the substantive use of the article.
The best I can do at this point is the suggest that the substantive use of the article is realized when the article functions like a noun and does not construe with another word/constituent to form a compound substantive constituent. This appears to cause problems for the idea of a demonstrative article functioning as a substantive, a concept I can't understand. For this reason I suspect my definition of substantive use of the article is wrong.
Cooper (v3 p. 2,204, 22.214.171.124) states: "It is not a sufficient description of the substantive article ... to say that it is substantive. The article is clearly a pronoun in the earlier and poetic literature and it shows demonstrative value, i.e. it has meanings and functions which would be represented in prose by ὅδε, οὗτος, ἐκεῖνος."
I suspect but cannot immediately demonstrate that Cooper's treatment of the article suffers from referential recursion, i.e., certain terms like substantive are used to define themselves but this is hidden by being distributed across several different levels of analysis. The reason I suspect this is the term substantive is repeated over and over again in Cooper's treatment of the article, page after page, in a mind numbing manner.
Difficulty with the meta-language is a framework problem in spades. My preferred framework for discussion of the Greek article is found in previously mentioned R. A. Hoyle SIL 2008.
 Richard A. Hoyle, Scenarios, discourse and translation. SIL 2008, 6.1 The meaning of the article in Greek, page 141ff.
τὸ πᾶν seems to mean in general
or the like, i.e. this is adverbial usage. I think here the article is not to be felt "strongly", this is standard Attic and I suppose even Koine usage.
With τὰ ... ἄχη, the article is "homerically" separated from the noun. Here, I think, it has a stronger, demonstrative force, the way Cooper says in the passages you're quoting. My tentative theory is that the separation here and elsewhere in Aeschylus works as a cue for reader/spectator to take the article with the stronger meaning.
I didn't have really time to really read any of Hoyle's work (though it looks really interesting...); however, it seems to be centered on New Testament usage, and I'd be cautious about extending the conclusions there to Aeschylus, because the "Homeric" uses of the article there are obviously archaic already in Attic.