Either/Or

One of Kierkegaard's more well-known books and his first major publication, Either/Or, is where Kierkegaard's use of pseudonyms first comes into major play. One of the biggest reasons Kierkegaard tends to be so misunderstood is that most of his well-known works, particularly the early ones, were written under different fictional names or "characters" that embodied particular worldviews, some of them radically different than Kierkegaard. His purpose was to present a first-person account of a particular way of life and allow the reader to reflect on their own life in response to it. 

In other words, instead of just telling someone directly what to believe, e.g. that pursuing pleasure above all else leads to despair, Kierkegaard would write a first-person narrative of a person pursuing pleasure and falling into despair, allowing the readers to judge for themselves and reflect on how much their own life might be similar.  This is where he is typically misunderstood, because people will quote passages from these books and attribute it to him, but that's exactly what he hoping wouldn't happen.  To provide a religious balance to the pseudonymous work, he would also publish uplifting Christian Discourses at the same time under his own name, but, of course, these tend to be neglected by a lot of modern readers.

Either/Or is the perfect example of this literary approach. The book is edited by a man named Victor Eremita, who claims to have found a collection of papers in an old desk he bought, and has decided to arrange and publish the papers, though he doesn't know exactly who wrote them. The first collection of papers is the personal diary of a nameless man Victor calls 'A', and the second is a number of letters by a judge named William written to 'A' in response to the life 'A' is living.

This is one of the reasons for the title of the book: 'A' and Judge William have two completely different approaches to life. 'A' is concerned only with possibility, while Judge William is interested in morality and actuality. Kierkegaard believed there were three main stages in a person's development: the aesthetic, the ethical, and the religious. In Either/Or, he is presenting two characters, 'A' and Judge William, who embody the first two stages, the aesthetic and the ethical. In other words, two different ways to live life: either aesthetically or ethically. [Kierkegaard would later bring the religious stage into this either/or more directly]

The collection of passages here will be from 'A', the aesthetic, someone whose interest in immediate wordly things was slowly leading to despair. Again, these are not Kierkegaard's personal beliefs.  This is instead a first-person depiction of one who is concerned only with worldly possibility (and the despair such a life leads to):

"I have, I believe, the courage to doubt everything; I have, I believe, the courage to fight against everything; but I do not have the courage to acknowledge anything, the courage to possess, to own, anything."

"What is going to happen? What will the future bring? I do not know...before me is continually an empty space, and I am propelled by a consequence that lies behind me. This life is turned around and dreadful, not to be endured."

"No one comes back from the dead; no one has come into the world without weeping. No one asks when one wants to come in; no one asks when one wants to go out."

"I don't feel like doing anything. I don't feel like riding - the motion is too powerful; I don't feel like walking - it is too tiring; I don't feel like lying down, for either I would have to stay down, and I don't feel like doing that, or I would have to get up again, and I don't feel like doing that, either."

"What is a poet? An unhappy person who conceals profound anguish in his heart but whose lips are so formed that as sighs and cries pass over them they sound like beautiful music...and people crowd around the poet and say to him, 'Sing again soon'- in other words, may new sufferings torture your soul, and may your lips continue to be formed as before, because your screams would only alarm us, but the music is charming."

"It takes a lot of naivete to believe that it helps to shout and scream in the world, as if one's fate would thereby be altered. Take what comes and avoid all complications."

"Marry, and you will regret it. Do not marry, and you will also regret it...laugh at the stupidities of the world, and you will regret it; weep over them, and you will also regret it...trust a girl, and you will regret it; do not trust her, and you will also regret it...hang yourself, and you will regret it; do not hang yourself, and you will also regret it...this, gentlemen, is the quintessence of all the wisdom of life."

"My soul has lost possibility. If I were to wish for something, I would wish not for wealth or power but for the passion of possibility, for the eye, eternally young, eternally ardent, that sees possibility everywhere. Pleasure disappoints; possibility does not."

Kierkegaard believed that many of the people in Copenhagen who claimed to be Christian were simply living aesthetic lives under a false guise of Christianity.  His hope was that they would identify with this character, relate to the despair that 'A' was experiencing, and, through this despair, be in a place where they could respond to the message of true Christianity.