by watcher » September 18th, 2006, 8:20 pm
David: you're right. The argument supplied by your friend cannot be one of necessity - at most, there is an argument from fittingness. The doctrine is certainly not "optional" for Catholics, although it's difficult to digest. There isn't really evident and strong support for it in Scripture, and there doesn't appear to be a strong body of historical evidence. Most disturbing is the fact that St. Thomas explicitly argued against the doctrine of the Immaculate Conception.
I've attached a link that I think provides a good overview of the issues. I hope you find it helpful. It's important to note that the Church doesn't teach that, in virtue of her Immaculate Conception, Mary did not need the merit of Christ's grace - just that she received it "in anticipation," and thus had that much more reason to hold Christ as her Savior. I think this is the only real point of debate, to be honest - could the grace of Christ's blood be bestowed prior to the shedding of His blood? People will try to turn the argument in a lot of different directions, but this is the main point.
The reason it seems so fitting that Mary was conceived without sin is that Christs inherits her humanity fully, without alteration or intervention to repair or prevent the inherited corruption of Original Sin. In this way, He receives his human nature from His mother in exactly the same fashion that we do. It's the "cleanest" way to do it. Like I said, that's not an argument from necessity - I don't think anyone has ever proved that there would have been anything unreasonable in an act of Divine intervention to prevent the transmission of Original Sin.
Lastly, and I'm not sure how people take miraculous apparitions, Our Lady of Lourdes appeared to Bernadette Soubirous in 1858, and told her "I am the Immaculate Conception," on March 25th of that year. My parents always taught me that a gentleman doesn't contradict a lady.
Cheers.