Faith is not a replacement for Truth. It is a hazard of the activity of Faith, we might say, that it is antithetical to having a descriptive representation of causality (reason) as a desideratum; however, even this view, that Faith is the negative opposite of Reason, is a narrow one. In the first place, we must understand the character of Reason, which is seen in the development of languages which are suitable to prescribed referents. This means that, ultimately, the origin and whatever meaning we attach to the devices of Reason are, in principle, beyond the scope of Reason itself, although language can and does become self-referent (leading to issues with mind-recursiveness, which many attempts at "language philosophy" have tried to settle). Thus, in a natural sense, we cannot expect Truth to take a propositional form, or even a propositional correspondence, which we might eke out from Reason alone, though Reason clearly has some kind of bearing on other forms of perception.
In the second place, to understand Faith, we must see that Reason, being essentially descriptive, does not engender action
of its own accord. This problem was recognized significantly during the Enlightenment, but reaches back further to ancient understanding which is manifest in the arts of so-called "divination". We may ask, What is the point at which we have enough data to make a decision? If we were to pursue a perfect fallibilism, such as that espoused by Mill (who was a devout Humean), we should say never
. If we went into an ice cream shop with ten-thousand flavors, or even just two, and we had to pick, we would never get a scoop. The "immediate action" (that is, action lacking medium
) represented by choosing a flavor is what Faith is really like. It may be doctrinal and highly structured--we might say operating within a larger scope of totality--because there is a reciprocal relationship between Reason and Faith; but one is not closer, nor further to Truth than the other.