A colleague of mine recently asked me the question how we can know, if not all roads lead to the top of the religious mountain (to God), which ones do. The following is how I responded:
The question you raise is the one that has been the obsession of philosophers since the Enlightenment, the epistemological one: how can we know?! The only answer I know to that question is circuitous, because I don't think there's a direct answer that will satisfy a true skeptic on any question of certitude.
For example: "How do I know my mind is not a brain in a vat of formaldehyde?" "How do I know I'm not in the Matrix"? "How do I know there's an external world corres-ponding to my perceptions?" "How do I know my memory is even sometimes reliable?" "How do I know the world did not come into existence only five minutes ago with all the appearance of age?"
None of these types of questions can be answered in a way that would conclusively demonstrate an answer to it in a way that would convince a skeptic of its certainty beyond all possible doubt. And the problem is compounded when we enter the arena of personal knowledge-- about other persons, about moral quandaries, about religious questions, etc.
In some respects, I would say that there are personal dispositional prerequisites for certain types of knowledge. For example, the person who has fallen in love with another sees qualities in that person to which others are blind. It's not that love is "blind," but rather that love has opened the eyes of the lover to those qualities that an indifferent person or hateful person would be blind.
How do we know, for example, that we have come to know a person we love sufficiently to trust him or her, particularly where it counts, say, in an engagement, for example? Is there any algorithm one could follow in order to know when one could safely commit to marriage? Of course not. So how do you arrive at such a personal commitment? By an irrational leap? Not exactly. One would try to learn everything possible about the person in an ordinary rational way. But there are dimension to knowledge that surpass any scientific algorithm, such as the intuitions and insights furnished by love (no "scientific" way to measure that).
What about God? Should we expect God, if He exists, to have any interest in revealing anything about Himself to us if we are indifferent to the demands of moral integrity and intellectual honesty in our lives? There are armchair philosophers who declare, "If there is a God, why doesn't he open the sky over New York City and reveal himself and declare: 'The guessing game is over: Behold, I EXIST!'"? But that strikes me as somewhat similar to the Romeo who waltzes up to a pretty Juliet, unknown to him, and breathlessly declares through his drooling mouth: "Hey, baby! How about we get it on tonight ... y'know, the horizontal tango??" Why would a Romeo with any brains expect to acquire intimate knowledge of any good and decent woman through such a proposal? The fellow is not morally or spiritually disposed to be open to true intimate knowledge of a woman. Why should it differ with God, assuming He exists?
Blaise Pascal (pictures left) knew that he couldn't convince his gambling buddies of any religious claims in a direct way, so he offered the famous Wager of his own (as I offered the apostate student). His objective wasn't to directly change the beliefs of his buddies. He knew what we believe to be true is beyond our immediate rational control. Yet he also knew that there are other things, such as our moral behavior and dispositions, that are well within our control. By showing what is at stake in betting on the truth or falsehood of Christianity (something that most everyone is already doing, one way or the other, by the little choices they are already making in their everyday lives), he wanted to launch them into a direction of living where they began caring about things within their control. Do they really care about truth enough to honestly seek it? Are they being honest with themselves about their own moral lives, or are they excusing behavior in themselves they would condemn in others, etc. The objective, for Pascal, was to get them to cultivate a disposition of humility, because he knew that one's disposition can alter what one is able to see. Just as the lover sees in his beloved qualities to which others are blind, one who begins to humbly seek truth, live honestly and morally, begins to perceive dimensions of the world to which others (and perhaps he himself previously) have been blind.
As to that which is more unique in the Christian claims, here's what one author said about the "road" analogy (Peter Kreeft in Fundamentals of the Faith, pictured left):"Christianity is not a system of man's search for God but a story of God's search for man. True religion is not like a cloud of incense wafting up from special spirits into the nostrils of a waiting God, but like a Father's hand thrust downward to rescure the fallen. Throughout the Bible, man-made religion fails. There is no uman way up the mountain, only a divine way down. 'No man has seen God at any time. The only begotten Son who is in the bosom of the Father, he has made him known.'
"If we made the roads, it would indeed be arrogant to claim that any one road is the only valid one, for all human things are equal, at least in all being human, finite, and mixtures of good and bad. If we made the roads, it would be as stupid to absolutize one of them as to absolutize one art form, one political system, or one way of skinning a cat. But if God made the road, we must find out whether he made many or one. If he made only one, then the shoe is on the other foot: it is humility, not arrogance, to accept this one road from God, and it is arrogance, not humility, to insist that our man-made roads are as good as God's God-made one.
"But which assumption is true? Even if the pluralistic one is true, not all religions are equal, for then one religion is worse and more arrogant than all others, for it centers on one who claimed, 'I am the Way, the Truth, and the Life; no man can come to the Father but by me.'"A lot more to be said, of course, but there's how I would begin addressing the sophisticated philosophical grilling that's coming from your Socratic self over there.