Reading this over, I realized that I should clarify something. When S.K. was talking about "double-mindedness" he was not thinking of those who have religious doubt. He was targetting those who were happy little christians on Sunday, and the rest of the week lived as good citizens of the world.|
At the time that he was writing, Denmark was a "Christian nation" and every child born was automatically a Christian. He viewed this situation as being very detrimental to achieving purity. "There's no need to struggle. I've been baptized, I go to church. Maybe not every Sunday, but there's no need for fanaticism." Small wonder that the articles he wrote in the last few years of his life were published together as a book called "Attack upon Christendom."
For Kierkegaard, the life of faith is unthinkable without doubt. If there is no doubt, then there is no faith, only certainty. Yet if God were such that He could be understood by the human mind, he most certainly would not be God.