In his Concluding Unscientific Postscript, Soren Kierkegaard tells us that "truth is subjectivity". Like so many things Kierkegaardian, this lends itself easily to quoting, but not so easily to understanding. Apart from the difficulties I find in following his arguments, all of which are rooted in personal psychological insight, there is also the problem of its own subjectivity. Kierkegaard wants to be a Christian and asks how this might be possible. Unless one shares his faith, it is easy to lose sight of just how applicable to every serious commitment it is.
One might think becoming a Christian is easily accomplished; a large chunk of the world's population is Christian and at the time of his writing, in Denmark, the place of his writing, everyone was a Christian. But SK tells us in another work (Attack on Christendom) that "when everyone is a Christian, no one is a Christian". Nominal assent to objective truth, is not Christianity; only a profound subjective experience makes one a Christian, and only then does it become truth. Thus, truth is subjectivity.
This being the case, SK must necessarily speak out of his own subjectivity; it has to be specific to his own struggle to believe; no generalizations are possible. Nevertheless, we see how applicable this existential and subjective absorption is to whatever "truth" we wish to create. Create? For SK, the only truth there is, or at least the only truth that matters, is that which becomes true in us, and that is a happening.
For SK, Christianity is like one big koan. It is objectively and intellectually ungraspable. It has to be transformatively experienced to be real. If visions of tears at the altar come to mind this is not what he had in mind. For him, the realization of truth subjectively was something more along the lines of satori or that "turning about in the depths of the mind" which others call enlightenment.
There are two aspects to this koan. With reference to Paul's observation that the "gospel" is "to the Greeks (philosophers) foolishness, and to the Jews (the religious) a scandal", SK considers how he might overcome the Greek and the Jew in himself. One aspect of his answer is his (in)famous "leap of faith".
Christianity is foolishness to the philosophers because it is historical; it works from something believed to have happened, not from something thought through. It is concrete. For the religious, specifically the Jews in whose religious context it takes place, it is scandalous because it declares this man here, the one relieving himself behind the tree, is God. In either case, it is mind-bending and mind stopping, and thus requires a transformative experience to become "true".
We needn’t concern ourselves with the objective truth of Christianity, or with Christianity at all, to get a sense in which all transformative “truth” must necessarily be subjective.
You can check out Scott's other miscellaneous writings here.