Kangas writes that by contrast with Plato, for Vigilius Haufniensis, Kierkegaard's pseudonymous author of The Concept of Anxiety, "the instant of eternity has to be thought of as the 'extreme opposite' of eternity" (p. 189). He continues:
The instant, in other words, is not allowed to be reduced to mere evanescence or illusion; rather, it is precisely the real. The event is not a passage to reality, but reality itself. Or more simply: passage as such is real, identity is illusion. This evaluation of what remains between being and nonbeing is conditioned on defining eternity with a forward direction. Eternity is not what remains eternally self-present, or what can be reduced to that, but what never ceases to beckon and threaten from the future. The eternal cannot as such be integrated into the present but remains essentially futural: the present and the eternal are thus extreme opposites. This essential gap, the excessive futurity of the eternal, awakens precisely anxiety. And anxiety imposes the most strenuous demand upon the subject.
(ibid., Kangas' emphases, my bold)
Why would the recognition of a reality of passage be conditioned upon any sort of eternity, or indeed, an extreme dialectics? Is the real being reified surreptitiously for the sake of dialectic, in contradiction to any professed relaxation within the anarchy of the instant? Well, we are speaking of passage as such, passage considered apophantically. In what sense aren't we speaking of the real from within an idealism?
I harbor serious doubts about excesses of futurity. Are these doubts consistent with a practice of ataraxia? How does the skeptic deal with the sudden, existentially? Is there any existential import to skepticism—would it be arrogant to deny any such importance, as arrogant as the denial of edifying discourses, perhaps?
Possibly there is no merely about the evanescent.