Followers of Zeus claimed that it was with him that Themis produced the Moirai, three Fates. A fragment of Pindar, however, tells that the Moirai were already present at the nuptials of Zeus and Themis; that in fact the Moirai rose with Themis from the springs of Okeanos the encircling world-ocean and accompanied her up the bright sun-path to meet Zeus at Mount Olympus.-- Wikipedia entry on Themis.
I have to assume that the academics I've quoted on the subject of Moira's co-existence with Themis were influenced by something like the Pindar fragment cited above. In 2010's LURKERS ON THE THRESHOLDS, I wrote:
Just as [F.M.] Cornford had shown that Moira, a sanctity older than the gods, was identical with the origin of social order, so Miss [Jane Ellen] Harrison pointed to the ensuing process of social evolution, where Themis represents the behavior dictated by social conscience... Above all, Themis was "Justice in the realm of Zeus," which checked the primitive law of sacrifice and atonement, symbolized in a Mother Goddess who suffered a yearly death and rebirth through her son.-- Henderson, THRESHOLDS OF INITIATION, PP. 10-11.
I haven't read Harrison's THEMIS and so can't be sure if Henderson has correctly represented her views. Still, I also pointed out in LURKERS that Ernst Cassirer entertained similar views, so to some extent the opposition of Moira and Themis has become independent of Harrison's specific views. For Cassirer, Moira represents human governance by a god-centered, "mythical" mode while Themis represents a man-centered "ethical" mode.
I've devoted considerable space to the difference between the Frye-derived concepts of "the overthought" and "the underthought," which I've aligned with the literary modes of "realism" and "escapism" respectively. Further, I would add that the "overthought," the more logical and discursive function of literature has displaced the function of the symbolically associative "underthought" in the world of criticism much as the ideal of Themis supposedly replaced that of Moira.
And yet, even though there's a place for works dominated by rational overthought or by "irrational" underthought, my concept of pluralistic tolerance doesn't keep me from finding superior those works in which overthought and underthought are balanced. In such works, the artist has access to what Jung called "the collective unconscious" and the many archetypes found therein, rather than his simply using discrete symbols for the sake of allegorical illustration.
Perhaps the best illustration of the difference might be the various iterations of the STAR TREK franchise. Though there are certainly some inferior episodes within the three seasons of "Classic Trek," Roddenberry in his capacity as head producer (for the first two seasons, at least) infused the show with a substructure of mythical ideas that balanced the show's apparent enshrinement of sweet reason.
Years ago I engaged in a mammoth re-watch of most of the TREK epigoni, all except for NEXT GENERATION. I searched in vain for any sustained use of an archetype with the mythic power I've associated with "Moira." But even though a lot of these episodes were entertaining, the writers of the epigoni had next to no understanding as to how to invoke the deep level of the underthought. Rational overthought dominates almost everything, and for the most part there's no sense that any other mode of thought can even exist.
Vulcans were not very popular with the executive producers of the epigoni up until the last series, ENTERPRISE. Even in that series, the series-makers were not able to grasp the dramatic contrast of Vulcan culture's conflict between impulse and rationality. But if there was any episode that best shows the producers' incompetence in the realm of Moira, it would be the 1997 VOYAGER episode, "Blood Fever."
Here the purely rational drama dwells upon regular character B'Eleanna Torres and her interaction with a minor crewperson, a Vulcan male named Vorik. Because the starship Voyager is far from the parent Federation and its planets, Vorik experienced a "pon farr" just as Spock did in "Amok Time." Like Spock, Vorik desires to get back to his homeworld to marry and spawn a designated fiancee. However, when circumstances seem to frustrate Spock in this goal, he at least contemplates having sex with a female crewperson to defuse his sexual torment. Captain Kirk makes it possible for Spock to carry out his ancient rituals of "marriage or challenge," but no one aboard Voyager can do this for Vorik. He works a Vulcan whammy on Torres, almost causing her to desire to mate with him. However, because such forced nuptials would be condemned as immortal by the show's audience, Torres is able to resist the Vulcan mind-magic. Finally Vorik initiates the "marriage or challenge" ritual, but this time, "the bone gets to fight." Torres roundly defeats Vorik in unarmed combat and defuses both his sexual desire and her own.
Now, the basic idea of a female character standing against a male aggressor CAN be archetypal. But here the writer of "Blood Fever," one Lisa Klink, merely uses both Vorik and Torres as flat representations of male desire and female resistance respectively. "Blood Fever" is by no means the worst example of a latter-day TREK-tale that has "too much Themis on its mind." Nowhere in the episode is there the sense that the "pon farr" is rooted in a centuries-old ritual designed to organize the interactions of males and females. Instead, it's just an inconvenient alien quirk that has to be defused so that Vorik can go back to being a useful member of the crew. (Not surprisingly, he never has a major plot devoted to him afterward.)
This suggests to me that the author's ability to make free associations with symbols has to be to some extent independent of moral considerations. Authors who are too concerned with framing moral messages cut themselves off from the depths of their own creativity. Thus the concept of Moira underlying Themis gives literary support to the philosophical opinion of Friedrich Nietzsche:
“Almost everything we call "higher culture" is based on the spiritualization of cruelty.”