In the 'Concluding Unscientific Postscript' Kierkegaard radically confronts what was the mainstream theological accent, i.e. to prove God and the authenticity of religious scriptures objectively with reasoning. It is crucial to differentiate his standpoint with who believe that faith and reason, subjectivity and objectivity, are two wings of the same bird and an individual can use either to find God.
Instead, he expresses that faith does not in need of any proof; furthermore, scientific proof is the enemy of faith. He rejects that faith can be derived by rational contemplations: “Faith does not result simply from a scientific inquiry; it does not come directly at all.” Furthermore, he names science as what can demoralise individuals. (pp. 377-80)
Furthermore, I may read Kierkegaard’s assertion that “because I cannot know God objectively” as his belief in an epistemological impossibility of approaching a subjective matter, here God, objectively. His remarks in another section of the text like saying that “God is a subject, and therefore exists only for subjectivity in inwardness” may support this view. It means that, in Kierkegaard’s view, the need for faith and the risk accompanied with it is not something that arisen because of the lack of scientific certainty an individual may have now but can be answered in future. Instead, he means that grasping God, as a subjective matter, epistemologically merely is possible by inwardness. (p. 379)
In Kierkegaard’s view, the more objective reality is acquired through scientific inquiry, the less the infinite passion of faith. In other words, certainty and faith are fundamentally mutually exclusive, as the former leaves no room for the latter. However, an individual grasps the objective certainty in a gradual manner, and even it is revocable. So faith is a risk of leaping the gap of uncertainty that never can be compensated with objective certainty. (p. 381)