One day in my Ecumenism class an insight stood out to me. We were discussing how the role of the Papacy makes Christian unity difficult. The East upholds primacy, but rejects universality. Protestants generally reject both claims, and that is even if we can get them to agree on Catholics being Christians at all! We read a line in some famous document that said, to the effect that the Papacy is the chief stumbling block to reunion. We were all talking about reimaging a Papacy that surrendered no essentials, but still fostered unity, when it hit me.

I raised my hand and offered this comment to my professor. I don't think he liked it. In fact, I think he was a little offended, because his ecumenical endevours deal mostly with Protestant Christians.

If you were to ask me, the chief stumbling block to Christian union is not the Papacy, but the Protestant doctrine of Sola Scriptura. If every man is his own final authority on Scripture, then it means he is also his own final authority on the nature and mission of the Church and the Person of Jesus Christ, of the doctrine of the Trinity, of the role of the sacraments, and of a million other things.

There can be no unity without a final, visible and common source of union. That is the Papacy. But Sola Scriptura, not the Papacy, has led to 30,000 Protestant denominations. Sure, Luther, Calvin and the rest rejected the Papacy, but they all rejected each other as well, and they did so precisely because of Sola Scriptura. They rejected the Pope because of their private interpretation of Scripture.

Don't believe me? Here is the historically accurate quote of Luther's famous Diet of Worms speech: 

Unless I am convinced by the testimony of the Holy Scriptures or by evident reason-for I can believe neither pope nor councils alone, as it is clear that they have erred repeatedly and contradicted themselves-I consider myself convicted by the testimony of Holy Scripture, which is my basis; my conscience is captive to the Word of God. Thus I cannot and will not recant, because acting against one's conscience is neither safe nor sound. God help me. Amen.

When everyone is a Pope, no one is Pope.