Can a Christian be an Existentialist & a Mystic?

A 19th century philosophy known as Existentialism teaches that the highest truth is subjective (not objective), reason is worthless, and experience, personal choice, views, and absolutes are minimized. Soren Kierkegaard is known as the father of this philosophy and today this philosophy has invaded the church. This philosophy reins in the Charismatic movement, however it has started or has leaked into the non charismatic church as so many these days do not like rigid Bible study, do not like to read theology books, and or call someone a legalist and or other names for holding to the scripture. Mysticism is an idea that spiritual truth is found inward. Again lots in the Charismatic movement hold to this view, and also some in the professing evangelical non charismatic church as well.

The chapter on reason from a certain book I was reading last night did not paint these philosophies in a very positive light and I would agree, and personally run into such types all the time on FB, and even sometimes on this board, so there may be Mystics and Existentialists on the BB! Well this board is not nearly as bad as another board I was on 3 years ago which I sadly confess was probably filled with False converts whom made a false profession of faith, but their battle against Biblical reason, which basically said the Bible is not the sole authority, but a secondary authority in their perspective on truth, told me nothing but they were probably false converts. Also many express their affirmation of these views with the statement that they do not read books nor commentaries but only the Bible, which tells me they do not want their views challenged. So what say you?

PS- Not a Cal vs. Armin thread.