"potuit, decuit, ergo fecit"/"God could do it, it was appropriate, therefore he did it" - St. Anselm of Canterbury doctor of the Catholic Church
Phrases like these make me weary of studying theology. I would prefer to be a physicist or chemist - something with empirical evidence. But I suck at science so I'm a History student who reads theology for personal enlightenment.
This is the phrase which John Duns Scotus used in the Middle Ages to 'prove' the immaculate conception (sinlessness of Mary). (for other terrible things about Duns Scotus see Jared's blog on why he isn't a Roman Catholic). To be honest that quote is a really bad argument and goes against several other Christian principles. The fact that a great philosopher and theologian like St. Anselm didn't notice it's flaws is simply another proof of the near infinite ineptitude of humanity.
First of all, 'God could do it'. I believe it was God himself/Jesus who said "with God all things are possible" (Mt 19:26). Now when you learn philosophy you actually discover that Jesus was wrong, he can't do 'all things'. He can't microwave a taco too hot for himself to eat, just as he cannot create a triangular circle (mutually exclusive statements). He is limited to logic and his character - therefore I guess reason is divine if even God can't escape it. But in any case this first phrase is a misnomer.
"it was appropriate" - This is more annoying to refute as I now reside in a communion which believes it is God's mouthpiece. However I would still argue that it is very difficult to determine what God thinks is appropriate. Especially regarding Mary whom divine revelation (Tradition and Scripture) tell us very little about already. How do you presume to know the mind of an infinite unknowable (see previous post) being? very carefully...
"therefore he did it" - Once again no proof whatsoever. Ironically an apparition/superstition of Mary appeared to many monks in the Reformation era which actually claim the Virgin told them that she was born with original sin. On a side note I have no idea why Mary comes back as a ghost all the time and does what the Holy Spirit is supposed to do - I guess he's been getting lazy or something. Anyway, once again we make a claim that God did something without empiracl knowledge or even revelation. I guess it comes down to Catholicism's: "some people look at illustrius titles for Mary and say why? I look at them and say why not".
Finally it's a ridiculous argument in that it's very possible for God to make me lose 90 pounds in my sleep, it would be appropriate, and therefore he must've done it. But he didn't... And so false logic stewed over for 500 years would become infallible dogma on December 8, 1854 (154 years to this week).
I've been reading "The Age of Reason" by Thomas Paine and I read a quote the other day that I liked: "Infidelity does not consist in believing, or in disbelieving; it consists in professing to believe what he does not believe."
This seems to be the foundation of the Anglican Church at least. But to me it's not so much that it is a lack of fidelty to disbelieve but that I think it should have certain consequences. It should never be a sin not to believe but one shouldn't take communion if they don't believe. So if you don't believe or at least see yourself believing in the Immaculate Conception then don't be Catholic, if you can't see yourself believing that Muslim Suicide Bombers have just as valid a path to Heaven as you do, then don't be a Unitarian or United Christian. And if you even consider choosing between the options I've just given you don't become a Presbyterian, because you believed you had a libertarian free will between those options and really you're totally depraved an therefore only able to choose the sinful unitarian option...it requires special grace to choose Catholicism.
Gah, I must start studying for this world religions exam and begin memorizing part of the Qu'ran... which is like a more boring and repetative Old Testament.