The Roman Catholic Church even having a "living Magesterium" has certainly not protected it from various schisms, factions, disagreements and battles over its history. The Franciscans disagreed with the Dominicans, they didn't agree with the Augustinians and none of them liked the Jesuits. You have liberal, conservative, traditionalist and sedevacanist factions even more so today. Look at any number of polls to see that you are far from having a majority of Catholics that agree on or accept everything your magesterium HAS decreed.
Like always, Christians MUST appeal to Scripture - and so did the early fathers of the church - as it stands alone as the OBJECTIVE and inerrant, divinely-inspired word of God. If THAT isn't authoritative, what else is better? On the major tenets of the Christian faith - those doctrines clearly taught in Scripture and spelled out in the earliest creeds - ARE what makes a person a Christian. It is far from a mere label. I know it is a common theme of FRoman Catholics to assert that they represent the church that is the same as the one begun by Christ, but an honest Catholic must acknowledge that their church cannot be shown to teach today what was used as a measuring rod for the rule of faith way back then - it's called:
"Quod semper, quod ubique, quod ab omnibus" literally means, "what always, what everywhere, what by everyone." This is the standard test for authentic catholic (i.e. universal) Christian doctrine, as proposed by the Church Father, St. Vincent of Lerins (died c. 445). It means that a Christian teaching is to be accepted as authentic and universal doctrine if it passes the test as what has been held by believers "always, everywhere, and by everyone."http://wiki.answers.com/Q/What_is_the_translation_of_quod_semper_quod_ubique_quod_abomnibus
You cannot be honest and insist this remains true in the RCC today. God's word is clear on the main doctrines that determine authentic Christianity. The early creeds were based upon it because they recognized no higher authority. It means what it says and hiding behind a "that's your own private interpretation of Scripture" is a ruse. The Apostles knew that, the Early Church Fathers knew that and faithful Christians today STILL know that.
Like always, Christians MUST appeal to Scripture - and so did the early fathers of the church - as it stands alone as the OBJECTIVE and inerrant, divinely-inspired word of God. If THAT isn't authoritative, what else is better?
Catholics are constantly appealing to Scripture and no one in the Catholic Church questions its authority. But to hold to the authority of Scripture is not the same as having it as the sole authority. From Scripture itself we know that Jesus Christ established the Church with authority and sent the Holy Spirit teach and guard it. To reject this is to reject Scripture itself.
Additionally, despite the claims of sola Scriptura, Protestants in fact do not actually act this way. Instead they bring some basic theological assumptions to the interpretation of Scripture which they inherited from the Reformers. Thus they are just as wedded to their own tradition as are Catholics.
God's word is clear on the main doctrines that determine authentic Christianity.
If this is so then why do Protestants disagree among themselves and why do they teach doctrines that were unheard of in the early church and for the next 1500 years?
It [Scripture] means what it says and hiding behind a "that's your own private interpretation of Scripture" is a ruse.
What Scripture says is not the same as what you says it says, this is only your private opinion on the matter. I, and many Catholics, find the competing Protestant interpretations of Scripture wanting. As well as having the authority of God's church behind them, the Catholic interpretation of Scripture just makes more sense.