Kierkegaard is sometimes understood to be a virtue ethics theorist, that is he has a view of ethics derived from Aristotle’s discussion of excellence, habits and reflection in relation to action in a community. This is a view of ethics which emphasises the learning of correct habits in a well balanced personality that interacts with others successfully. This understanding generally refers to the two very long letters of William to an unnamed Young Man which make up most of Either/Or II.
Kierkegaard himself is not, however, expressing himself through William, and he makes that very clear in the very last section of Concluding Unscientific Postscript a few years later. It should be clear enough that Kierkegaard sets up the religious perspective in the sermon that forms the very final section of Either/Or as distinct from William’s point of view. William attaches the sermon to his second letter but simply does not get that his ethics does not encompass religion at its deepest. There are a number of hints that William is a complacent character of limited understanding at abstract and common sense levels, within his letters, and in Victor Eremita’s Preface to Either/Or. There are plenty of reasons to see the aesthetic fragments of Either/Or I as encompassing insights necessary to the religious lacking in a purely ethical perspetive.
Nevertheless, the people who have seen Kierkegaard as William and as endorsing his version of virtue ethics are not just being obtuse. Kierkegaard us trying to draw his readers into a complete immersion in every perspective he explores, there is no blame in doing so. We need to see what happens when philosophers take up one voice in Kierkegaard’s text as the voice of Kierkegaard.
Even taking William as the Voice, we can see some ambiguity in what he says. He takes ethics to be what emerges from a commitment to repetition over time (not in the deepest sense of repetition for Kierkegaard, but that issue will have to wait for another time), including the commitment to marriage, in which he claims that the fist moments of love are preserved in marriage. He recognises possible contradiction of the preservation of the moment over time, but assumes its resolution. His view of life, and therefore his view of ethics, has referred to a contradiction he cannot confront. As far as virtue theory is concerned, on Kierkgaard’s account it looks like it is troubled by an unresolved tension between the moment of experience and enduring experience, habit.
William’s account is not theoretical, but does implicitly refer to views of ethics which resemble Kant, Aristotle, and Hegel. Following on from the last point, Kierkegaard is implying that Hegel does not resolve the contradictions he claims to have, he has only covered over them. We can see Hegel as attempting to resolve Aristotelian ethics with Kantian ethics, and that makes a good frame for thinking about William’s letters. In that context, we can think about Fear and Trembling where Kierkegaard suggests that ethics can be seen both as Kantian universal abstraction and Aristotelian virtue, with a very social content.
The above suggests that Kierkegaard regards virtue theory as caught between contradiction between the moment and habit (the contradiction between the aesthetic and the ethical) and the contradiction between habits and the abstraction of the rules governing those habits (virtue theory and Kantian universality).