The value of this work is that it correctly argues that faith is ultimately a choice that cannot be completely supported by logic or rational proof. It was Kierkegaard's experience of losing the chance to be with the person he loved that forced him to confront the absurd nature of faith. Although believers in many religions will argue that their faith is logical and rational, Kierkegaard fully grasped that if conviction is based fully on logic, it does not need faith to support it.
Perhaps the best metaphor can be found in the New Testament passage where Christ invites Peter to walk on water -- Peter takes a step with faith and does not sink, but then looks down, and begins to evaluate the situation using his rational mind, and begins to sink. True faith walks on water. Only true faith could be sufficient to base a life on the conviction that a dead guy in Jerusalem 2,000 years ago came back from the dead and has his own kingdom where his followers will live forever in eternal bliss. On the other hand, this conviction has become so entrenched in the popular culture of the last 2,000 years that it has just become an unremarkable backdrop to the modern world and is considered a socially acceptable belief.
The challenge for a modern christian is to find true faith when they mistakenly believe that the story of Jesus Christ is completely supported by logic and rational thinking. The mere act of mentally assenting to what has been accepted in popular culture, a broad and shallow idea that God and Jesus exist, is not faith at all; just an unexamined conclusion of a lazy mind that has not yet questioned its own surroundings. True faith is a radical departure from the status quo, a renewal of personal conviction despite all contradictions and a recognition of UNCERTAINTY. Without a recognition of uncertainty, faith has no meaning. The strength of true faith is that it acknowledges that uncertainty exists, and yet still forges on in spite of the uncertainty, willingly accepting and embracing the consequences of conviction in the face of uncertainty. There is not fear that the conviction may be misled and flinching because of the uncertainty, there is a recognition that this lack of absolute rational proof and certainty is what gives faith its supreme virtue. This is what makes faith courageous and is something that only mortal humans can do, since angels are blessed with absolute knowledge whereas humans are blessed with uncertainty, which is the only way that true freedom can exist. Without this freedom, the choice of "faith" would not be possible, would not be courageous, and would not make mortals eligible for the reward of heaven.
The believer who claims that all faith is logical has not yet come to the moment of testing, like Abraham, like Kierkegaard, where the object of the soul's deepest longing and only happiness is seen, but yet out of reach. For Kierkegaard it was the girl he loved, that he could never be with, but yet he retained hope and transformed that hope into a lifetime of faith. The personal pain of such an experience leads a person to exclaim "it doesn't make sense!" Only when one reaches the point where it just doesn't make sense can the ultimate nature of real and profound faith be experienced and put into action. Anything else is a shallow beginning, and not yet a sufficient faith to walk on water, just as Peter found when he was invited to take that step...
This book is full of such profound insight because Kierkegaard understood this and knew that faith was not a shallow, cheap or easy achievement:
"In those old days it was different. For then faith was a task for a whole lifetime, not a skill thought to be acquired in either days or weeks. When the old campaigner approached the end, had fought the good fight, and kept his faith, his heart was still young enough not to have forgotten the fear and trembling that disciplined his youth...." (p.42)
