"There have been men before now who get so interested in proving the existence of God that they came to care nothing for God Himself...as if the good Lord had nothing to do but exist! There have been some who were so occupied in spreading Christianity that they never gave a thought to Christ."
C S Lewis, The Great Divorce
People who have engaged in ecumenical dialogues on a regular basis can sympathize with Professor Lewis' lament. This is true also for anyone who has watched a proselytizer (as opposed to an evangelist) at work. One unfortunate trend I have noticed in discussions of an ecumenical-turned-apologetics nature is the tendency of one or both parties latching onto a position and then forgetting why he (or they) hold to that position in the first place. I've seen this happen many times before, and it is done by Catholics, Protestants, Orthodox, non-Christians, and non-theists alike.
The most egregious example which I have yet encountered is in arguing over the Doctrine of Perpetual Virginity. Catholics assent (or at the least consent) to this doctrine--that Our Lady was a perpetual virgin--and most Protestants who care either way (generally, though not exclusively fundamentalists and certain evangelicals) insist that she bore other children after Christ, implying that she had sexual relations with St Joseph her most chaste spouse*. Said Protestants argue that the Bible refers to James (and others) as "the brothers of Christ." Catholics respond by noting that adelphos is better translated "brethren" and that in the culture of the time and place would most certainly have included cousins. Others suggest that these may have been St Joseph's children of a previous marriage--stepbrothers--hence making sense of the way in which they rebuke Him as if they were His older siblings (or other relatives).
A challenge has been posed, a reasonable explanation proposed, and at this point the argument could stand as settled. It is at the very least reasonable to state that the evidence is silent as to whether St Mary had additional children; if neither side is won over, at the very least we have a point on which it really does make sense to "agree to disagree" without further quarrel, especially in the interest of Christian unity. Unfortunately, this is seldom the case. Catholics might forget that Protestants are not bound by the teachings of the Church--even if said teachings are true--because to the extent that they have not yet converted, they are not yet Catholics.
Protestants in general and Fundamentalists in particular in turn have to answer a question of their own. Why is it so imperative that Our Lady had additional children? To say "because the Bible says so" in this case is not an adequate response: the Bible does not say so. Rather, the Bible says that Christ has "brethren," which may or may not be literally younger siblings. A possible--even quite probable--explanation has even been given for the interpretation that these were literally brothers of Christ. What little surviving evidence we have concerning the Holy Family suggests that St Joseph was a bit older than Saint Mary, he was traditionally believed to have been a widower.
For the Catholic, this doctrine of Mary's perpetual virginity is a part of the deposit of faith, and is important for a number of reasons. First, because we are bound to believe what the Church teaches as matters of faith or morality. Second, because as then Cardinal Ratzinger and his friend Cardinal Von Balthasar have pointed out, Mary is a sign of the whole Church. But the Church is the spouse of Christ, and though some of her members may stray a bit she as a whole remains faithful to Him. Saint Mary's virginity is a sign of her faithfulness to God. She is faithful to the Father, by bearing only His Divine Son; to the Son, by being His mother alone**; to the Spirit, by accepting His unique indwelling in her as the sole form by which she would conceive.
For the Catholic, then, this doctrine really is important. For the Protestant, I can see no reason for obstinate opposition, especially not where it wreaks Christian unity. I am not insisting that all Protestants must embrace this as a doctrine of their own faith. I am, however, asking that more considerate Protestant question their motives for insisting against this doctrine. What consequences does this have for Christian unity? What about for faith, for hope, for charity?
*Note that chastity in a married relationship does not imply abstinence from sexual intercourse; however, we as Catholics believe that St Mary's perpetual virginity also implies St Joseph's abstinence from sexual relations after his betrothal to her.
**Consider: Mary and Joseph, as mother and foster-father to Jesus, would have been charged first and foremost with His care and protection. Since they both knew that He was to be of great importance--indeed, that He was the Messiah--it does not make sense that they would attempt to procreate after His birth, thus providing additional younger siblings who would place demands on them for protection and care. Rather, it makes very much sense that they would be focusing their time and energy and attention on the Child Jesus to the greatest extent possible, which would preclude having additional children and thus having sexual relations.
If you enjoyed this post, here are some related ones:
Apologetics: Argument and Motivation
Chesterton on Dogma
Anti-Catholic vs Counter-Catholic
C.S. Lewis on the Importance of "Good Work" in "Good Works" (Quote of the Day)
C.S. Lewis on Art, Artists, and Good Work (Quote of the Day)
Saint Dominic and Apologetics