When I first encountered the simple medieval procedure for testing the truth of revealed religion, I was thrilled. It only works negatively, though; so, it has its limits. The basic argument is that there is divinely revealed truth that is inaccessible to human reason on its own and there is divinely revealed truth that is accessible to human reason on its own. A revelatory tradition that teaches doctrines that conflict with what human reason is able to know is not trustworthy, and a revelatory tradition that teaches doctrines that accord with what human reason is able to know has not disqualified itself. This process does not assure the truthfulness of a revelatory tradition, but it does winnow out falsehood.
Yet, there are many problems with this procedure, including the frailty of human reason as manifested in most men. It is pleasant to think that human beings can easily overcome controversy through rational dialogue, but such dialectical ascent evades the bulk of mankind. Even the wisest find answers to the truly important questions difficult or indiscernible. Hence, the schoolmen argue for authority and divine revelation as assistance to the weak human mind. However, one must choose his authorities wisely; for we know that the world is full of liars and sowers of confusion. Therein, one sees the circular problem. How does the ignorant man wisely choose an authority to follow in order to spare him from his ignorance? In the end, each individual must make that choice, though the beneficial consequence of that choice is really required to make it.
The issue is quite practical. If we wish to serve God, how do we know whom to serve when, in our ignorance, we do not know who is telling the truth about ultimate matters? In the book of Genesis, we read the striking story of Abraham’s planned sacrifice of Isaac. The account serves to demonstrate Abraham’s faith and devotion, but a skeptical reader might think that Abraham was a naive dupe who happened, fortunately, to follow the true Lord (that hypothetical reader must not be too skeptical). For God’s command should have been repugnant to Abraham. Were he to have followed the aforementioned scholastic advice, he would have asked God to leave him. The pious man replies that Abraham trusted God more than he trusted his own sense of right and wrong, but that is precisely the problem. How does one discern messages from God from those of other sources without relying on one’s own wisdom?
Perhaps, Abraham developed enough trust in the Lord, gained from the many years during which he served God before he was asked to sacrifice his son, that he would obey despite the ostensibly heinous request. One might ask what the value of trust is if it is to be continuously questioned. Nonetheless, would not Abraham have good reason to suspect that the Adversary was attempting to lead him to evil under the guise of God? However, maybe one cannot mistake evil for God once one knows God.
These sorts of questions lead me to think that we have been blessed with more spiritual faculties than simply discursive or analytic reason. As I have written before, I think that we might have something like a faculty of faith. If the peasant can commune with God as well as the philosopher, perhaps our principal organ for dealing with the divine is not our mind. Abraham’s fidelity and righteousness might have resulted from his superior employment of this faculty.