When there is full parity of the opposites, attested by the ego's absolute participation in both, this necessarily leads to a suspension of the will, for the will can no longer operate when every motive has an equally strong countermotive. Since life cannot tolerate a standstill, a damming up of vital energy results, and this would lead to an insupportable condition did not the tension of opposites produce a new, uniting function that transcends them. This function arises quite naturally from the regression of libido caused by the blockage.[Ibid., par. 824.]
Although Jung doesn't explain the transcendent function in this exact way elsewhere, I take issue with the notion that the ego "participates absolutely in both of the Opposites" (or attitudes). I think that these depressions and break downs that lead to confrontations with the unconscious tend to be entirely the result of dysfunctional egoism (not of tension or conflict between ego and unconscious, per se). That is, the ego, one's sense of identity and conscious will, insists on living in a way that is not conducive to psychic balance or adaptation. Usually, this is a fractured or dissociated state in which instinctual libido cannot flow into conscious living. I see it as a state of decoherence or impaired interconnectivity. The psychic system is not efficiently organized, so libido bottlenecks and bogs down, cannot flow.
One doesn't have to consciously valuate the unconscious Opposite attitude to become depressed. Depression form many (probably even most) people is at first mysterious. Many depressed people feel that their bodies and personalities have let them down. But the bottlenecking of libido can lead to dangerous build-ups . . . and these tend to result in rash, sometimes self-destructive behavior. Jung would call the emotions that drive these rash behaviors and attitudes "affect".
What I suspect we are dealing with in these situations is a natural flowing source of energy like a river. The ego (as culture often dictates) dams up the river in certain ways (or smaller tributaries of the main river) by compartmentalizing/dissociating or insisting on rigid beliefs that are not actually conducive to functional humanness. The "antithesis" that rises up from the unconscious is the pressure of the flow of libido that has not been given enough channels to flow through.
At some point, this antithetical pressure might begin to seem appealing. The depressive ego approaches the "just kill me already!" phase, because the feeling of loss and anxiety and confusion is too much to bear. The individual loses a healthy sense of value for his or her life. But the antithetical impulse from the unconscious is merely the result of the damming of libido . . . which was probably an unconscious egoic choice (although in the case of trauma, there may be more going on . . . perhaps as Kalsched suggests). That is, the libido of the psyche is not truly aligned against the ego. It only seems this way to the ego that clings to its old paradigms so rigidly (and terribly) that any threat to those paradigms is seen as an attack or violation.
Of course, there are also times in which we have split conscious attitudes and the unconscious appears to back on more than another. We see this frequently in our dreams in which the dream ego feels some sense of conflict with another character. Sometimes these conflicts are fairly cordial and the other is an intimate or family member or friend. Sometimes it's a battle with a dangerous shadow figure (such as when we are consciously still completely opposed to the alternate attitude). In these situations, what Jung called the transcendent function may produce the beginning of a synthesis.
The ball I'd like to run with here (and the beginning of my redefinition) can be found in this beginning of synthesis. The so-called transcendent function is better called (in my opinion), the syzygy . . . as it is composed of two forces. The first force is the attractiveness of the Other, the Opposite attitude or orientation. As soon as that attitude stops becoming terrifying (the shadow) and begins to seem attractive, compelling, fascinating (even just a little), the transcendent function has begun. Out of the shadowy Other, the animi are born . . . and they tend to emerge gradually.
You should have seen all the poetry I wrote about the Dark Woman in the years before I started my anima work proper. She went from a seductress and betrayer to a Fallen woman who could be redeemed to a goddess misunderstood.
The other half of the syzygy is the hero, and there is (I feel) an exact accordance of the degree of attractiveness of the animi-Other with the degree of identification in the ego with the hero archetype. This is why I frequently call this archetype the "heroic ego" . . . it is meant to be identified with. Of course, there is instinctual libido and Otherness behind this heroic strength and drive . . . but we could see this as somehow conducted or inspired by a larger source of personality (larger than the ego). This larger personality, the Self, is pushing to broken parts together, one with each hand.
Therefore, the inclination of the hero is to fight against the dissociation or blockage in the psychic system, and equally, to love and move toward the animi. As I wrote in detail in the thread about the hero, this is why I feel that the characterization of the hero archetype as the dragon slayer or conqueror is psychically misguided. The archetypal hero's job is to oppose decoherence to the psychic system (often embodied by the Demon of the complex), love the animi-Self unconditionally, and eventually sacrifice her or himself for the "cause" of this love. I.e., the hero's libido and sense of power is not hers/his, it belongs and always belonged to the Self. And when it is no longer needed, because the ego has accepted the love of the animi-Self, the hero must die. To try to hold onto the hero after this time is to usurp the Self's libido. It is done not for the Self or the whole psyche, but for the empowerment and protection of the ego position.
This is why, at this turning point, if the heroic ego refuses to relinquish his or her power, the Demon possesses the hero . . . and what is believed to be heroic is actually Demonic (i.e., self-defensive, dissociated, static). Of course, no one succeeds in short-circuiting the Demon without first failing many times and falling into Demon-possessed inflation. But the instinctual libido trying to self-regulate the psychic system doesn't give up, so we will keep getting more chances. Eventually, if we are honorable and lucky, we will figure out that we must accept the loss of the heroic libido.
Some of this is a bit abstract or mythological, but I think it is a much better way to talk about the transcendent function than the more conventional Jungian approach. It puts a lot more flesh on the bone, in my opinion, and it leaves the theory a little less mystical and airy. Also, the original concept of the transcendent function that Jung offered tends to make too rigid an intellectual paradigm for my tastes. I.e., thesis, antithesis, synthesis . . . war of the Opposites, the mysterious rise of the Third Thing. I know what he was on about, but that language is too arcane, too occult.
It's also not entirely accurate, even as metaphor. For instance, Jung's notion gives way too much respect to the ego position in this paradigm. The Third Thing, the result of undertaking individuation and doing the animi work is not in any way a 50/50 blend of old ego position and new/unconscious position. I think we much more commonly experience these transformations as radical and not as even compromises. Yes, there is plenty of the old ego in the new ego, but the result of individuation Work is not a bargain, no a business transaction in which each party makes the best profit they can. More often, the ego is shatter, dissolved, and radically rebuilt. The orientation we end up with bears more resemblance to the antithetical attitude than to the thesis or original egoic attitude.
That this happens is perhaps confusing if we stick to Jung's terminology, but seen in the terms I presented it above, it make much more sense and becomes logical and easy to anticipate. Why then did Jung make this synthesis seem like such an even-handed compromise? My guess is that this is due to his own struggles with inflation (both archetypal/heroic and egoic/Demonic). Jung fought against his temptations of archetypal inflation mightily and frequently prescribed a "strong ego" and sense of groundedness with which to fend off these "anima temptations".
Sometimes we can buy a little time with this approach, but I think it is impractical. We can't have our cake and eat it to. If we are to learn, we must Fall, and to Fall is to suffer enormously. We cannot sit down smartly at the table with the Self and broker a reasonable deal. That is a transaction, not a myth, no a quest. If we do not end up in the belly of the beast, we cannot learn how to be individuants.
What is regrettable about this is that Jung seems to have followed this more mythic (as opposed to business transactional) path . . . and yet he was disinclined (perhaps for obvious reasons) to prescribe it in his psychological theories . My feeling is that he made too big a bogeyman out of inflation, probably because he was so ashamed of what it did to him. Jung was constantly recommending to others that they allow the psychic contents to be non-literalized, to be mythologized so that it's narrative could play out. Why then is inflation not treated this way in the Jungian method? Instead, it is a very literalized bogeyman and massive moral failing against which the only defense is willful resistance and a strong ego. Bullocks!
Jung deviated from his general approach on the issue of inflation and that (as he and all Jungians should know) is an indication of a complex getting tweaked. I won't go into this more here, because I've written about it elsewhere and it would also require too much digression, but it should be kept on the table as we examine Jung's notion of the transcendent function.