For a partial answer to Kierkegaard’s nihilism in the Concept of Irony, see page 293 in Annette Baier’s Postures of the Mind;
‘I shall suggest that the secular equivalent of faith in God , which we need in morality as well as in science or knowledge acquisition, is faith in the human community and it’s evolving procedures-in the prospects for many-handed cognitive ambitions and moral hopes.’ Etc.
https://books.google.com/books?id=kS73a3FOfeatures of an action OnsC&pg=PR9&lpg=PR9&dq=postures+of+the+mind&source=bl&ots=7kir7dgrPV&sig=LSHdD4YgwiRjq7kQyAEzxLzm19g&hl=en&sa=X&ei=hNPoVKjnOMynNsCxgPAJ&ved=0CFUQ6AEwCw#v=onepage&q=postures%20of%20the%20mind&f=false
Another part of the answer can be found in D.D. Raphael’s The Impartial Spectator, Adam Smith’s Moral Philosophy:
‘The relevant features of an action include its effects on some other person or persons, and here imaginative sympathy has an important role.’ Etc.
We are a part of a human community, even though we may vigorously dissent to the felt and expressed values of that community. In a very real sense, we can never reach a state of complete nihilism, as we were born into and reached our point of self-emancipation through that existential medium. Faith was all that was left to Kierkergaard, given his nihilist self-conception of a completely desolate, alienated relation to that community. We are impelled to dissent, yet we must live within, accept the paradoxical nature of our ‘nihilism’.