I am not sure I can do full justice to the questions about Roman Catholicism (from Tim and Kurt), but I will have a whack at it.
The distinction between the magisterial doctrine of sola Sciptura and the modern, individualistic solo Scriptura is, in my thinking, straightforward. Solo Scriptura maintains that the Bible is the only authority over “me,” and, fortunate for “me,” I am the only interpreter of the Bible who has any credibility and weight with “me.” In other words, solo Scriptura is “just me and my Bible.” And, human nature being what it is, it is not long before we wind up with “just me.”
By contrast, sola Scriptura does not claim that the Bible is the only religious authority in the lives of believers. Rather, the claim is that the Bible is the only religious authority in the lives of believers that has the two particular characteristics of infallibility and ultimacy. Infallibility means that Scripture, as the very word of God, does not make mistakes, does not err. It is the ultimate standard of what is right, and so I must always conform myself to it, and not go the other way around. I must not bend the Scriptures to fit what I (or others that I know) think might be more accurate, that accuracy determined elsewhere.
As an aside, one of the reasons why conservatives retreated to the word inerrancy was because liberals, bless their hearts, had begun nuancing the word “infallibility” to mean something more akin to “fallibility.” They would also do such things in the name of “honesty.” I am using the word infallibility in its older sense.
Ultimacy means that there is no court of appeals past the Bible. This is how I am using the word absolute. Biblical absolutism means biblical ultimacy. I do not bring other standards to evaluate Scripture; I am not to weigh the Bible in the balances of biology, astronomy, clinical psychology, oral legends, the book of Mormon, lexicography, or philosophical and rudderless Frenchmen.
I can (and must) bring other standards and authorities to bear to help me understand what the Scriptures are actually saying. The Bible teaches that I am as a Christian to submit myself to spiritual authorities other than the Bible. These authorities would include my parents (who taught me to love God before I could read), my church (which taught me, for example, to memorize Scripture), and Bauer’s Lexicon (which teaches me that eulogeo means to bless). But none of these genuine authorities in my life are ultimate or infallible, which is fine, because authority is not an all or nothing proposition. However, without the touchstone of an ultimate and infallible authority located at the top of the hierarchy, all lesser authorities will wither and die.
With regard to the communion of the saints, this is something that we confess every Sunday as we say the Creed. So what are we talking about? First, the context of what we are talking about. The context is a universe teeming with intelligent life, celebrating the goodness of God and riches of His grace. Contrary to the notions of Enlightenment materialism, we do not live in a universe that is mostly empty space, punctuated here and there with dead rock or flaming gas. Many educated Christians have mostly gone along with this materialism, and are now trying to defend the last ditch, which would be the reality of the soul within man. I do not think they will fare well because they long ago took spiritual man out of the only habitat where he can flourish, which is a spiritual world.
But the problem is not Protestantism vs. Catholicism here — the culprit is education in Enlightenment terms. And you will find as much accomodation on such points among educated (indoctrinated) Roman Catholics as you will among educated (domesticated and tenured) Protestants. Perhaps even more accommodation. Take the theory of evolution for example. Who has kept opposition to that particular Enlightenment folly alive? Conservative Protestants, and the holy father in Rome sees no tension between evolution and the creation account in Genesis.
Now this believing view of the universe can be simplistic and superstitious (as it has been in backwater parts of Spain and backwater parts of Tennessee), but it also has educated and erudite exponents (C.S. Lewis, for example). But it has to be insisted that the tendency to desacralize the world has nothing inherently Protestant about it. It is an inherent tendency of Enlightenment indoctrination centers, and yet when the problems start to appear, I see a lot of people suddenly becoming chary of their Protestantism — but never of their graduate degrees, which is where the problem actually arose.
Now in a world that has not been desacralized, what does this do to our devotional life, both personal and corporate? When the psalmist exhorts everything that has breath to praise the Lord, this presupposes (given the boundaries and nature of poetry) that all these things have the capacity to praise the Lord (which I believe) and not that they have the capacity to read and sing that particular psalm (which I do not believe). As a minister, if I cry out in a call to worship that the galaxies should bow down, (as a good Protestant) I am not presupposing anything about my relationship to those galaxies, and (as a pre-modernist) I am presupposing everything about those galaxies and their relationship to their Creator.
The twenty four elders in Revelation represent the Christian Church, and the Christian Church presents her requests to God. We should assume that every servant of God is directed by Him to serve and worship Him in a coherent manner. Individual saints in glory (individually and corporately) may or may not know anything about us. We are not given any information on that score. But we know that they are praying for and longing for the day of redemption just as we are, and that their prayers line up with ours. This is God’s department.
But if I single one of them out to submit my prayer requests to, then given the nature of the case, I must be doing two things. The first is what I discussed before — I must assume that he hears me. It is not enough to assume that it is possible that he hears me. If I have a choice (in a moment of danger) between praying to God in the name of Jesus, knowing that I will be heard, and praying to St. Thomas, not having any assurance that he will hear me at all, then I will pray to God every time. The only way I would ever pray to a saint is with the bedrock assumption that my chances of getting through are just as good as if I pray to God in the name of Jesus. And this leads to the second point that I did not touch on before. I also have to assume that the one to whom I am praying has a better “in” than I do. I have to assume a distance between God and me that the Bible does not encourage me to assume at all. Quite the reverse. If I pray the way the Bible instructs me to pray, then it makes no sense to afterwards turn to a lesser prayer, with a lesser mediator.
One other thing. We are taught in many places that God is a jealous God. His name is Jealousy. We should be exceedingly wary of any refined arguments (and any learned distinctions sliced lengthwise) that would bring us to the point where we could provoke that jealousy. God is jealous, and He is jealous with regard to this question of worship (of which prayer is an important part). The fact that humans can have it all worked out in their abstract theology (latria, hyperdulia, and dulia) such that they can admit to being an iconodule, but not an idolater, makes me hop in place in my impatient Protestant way.
Imagine a wife catching her husband kissing the chambermaid. “Ah, my dear,” he says. “I was meaning to talk to you about this. This is not what it appears. This is a species of what I have learned to call lesser-kissing. It doesn’t mean the same thing to me as when I am kissing you — kissing you, my love, my dear, my only sweet, is what I call special-kissing.”
“It may not mean the same thing to you,” she says, jealous and angry as she should be. “But it means the same thing to me.” And so she throws an expensive vase at his head, demonstrating an unwillingness to master some of the finer points of his theology.