Just finished reading this quote over at a comments site: "...what our Savior and the writers of the New Testament left mysterious or undefined...Reason should never lead faith, for faith is the substance of what we do not know." There it is again, theological Jellyfishism: amorphous vapidity is more spiritual than certainty.
Now, as the foul fruits of the so-called Higher Criticism have demonstarted, if Reason becomes the Magisterium (Luther), then, yes, we need to put Reason in its place. But if we apply (sanctified) reason properly, as a servant of faith, not as faith's dictator, then it fulfills the vital role of checking our natural tendency to indulge in spiritual fantasies, or as Paul put it in Colossians 2: "[avoid the blather of those] insisting on self-abasement and worship of angels, taking [their] stand on visions, puffed up without reason by [their] sensuous mind...[such practices might give] indeed an appearance of wisdom in promoting rigor of devotion and self-abasement and severity to the body, but they are of no value in checking the indulgence of the flesh." (Interestingly enough, an alternate reading is even more scathing: "are of no value, serving only to indulge the flesh.")
Flesh loves to pretend it is more-spiritual-than-thou: the more nebulous my beliefs, the more divine I am. Don't shackle me with your prosaic and Philistine propositional perorations! No, can't you see that we must bathe ourselves in oceans of pearlescent piffle, luxuriate in the foamy fluff of flimflam falderol, lest we land our guilty fannies on the obdurate granite of Fallenness?