How do we know the Church and the scriptures are infallible?

I was recently grilling a Protestant on his blog regarding the basis of the doctrine of sola scriptura (see the post titled “Sola Scriptura and Tradition” on the blog Theo-Drama). He responded by drawing a comparison between sola scriptura and the Catholic doctrine of the infallibility of the Church.

To him sola scriptura means that “scripture is the only source of authority that is both infallible and unchangeable (emphasis in original). A nice, clear definition.

My question to him was whether we can know infallibly that the scriptures are infallible; or in other words, do we have it from an infallible source? Since sola scriptura means that the scriptures are the only infallible source, then obviously the infallible source for sola scriptura can only be the scriptures themselves. But isn’t it circular to argue that we believe the scriptures are infallible because they say they’re infallible?

Even granting that that can be a valid argument for sola scriptura, there is also the question of whether any scripture passage can be said to teach the infallibility of the Bible – that is, the 66 books of the Protestant Bible in particular. I grant that verses may be found which refer to “the scriptures” as God’s word, and God’s word is, of course, infallible. But none which state which books are, in fact, scripture.

So in the end it seems clear, on the premise that no other infallible source exists, that sola scriptura does not come from an infallible source.

Note that that is my only conclusion thus far:  That we have no infallible source which defines the only infallible source. I’m not arguing that we have no way of knowing what the canon consists of. Perhaps it can be figured out in other ways. But by the terms of sola scriptura, those ways can’t be infallible.

He counter-argued that in terms of circularity, the Catholic is in the same position as the Protestant, since both believe a source to be infallible, based solely on the word of that source itself. By this he means that the Catholic believes in the infalliblity of the Church, based on the word of the Church. He stopped short of admitting outright that the Protestant is reasoning circularly, but implied that if the Protestant’s reasoning is circular, then so is the Catholic’s.

But even granting the premise that the Catholic believes in the infallibility of the Church based solely on the Church’s own word, the Catholic is not, in fact, in the same position as the Protestant. The difference is that the Church, in naming itself infallible, identifies that which is infallible. The Church leaves no doubt what the infallible Church consists of. Whereas the Protestant Bible leaves the contents of the scriptures to be assumed or guessed at, or arrived at by human reasoning, or what have you.

But in any event, I do not concede that the Catholic reasons circularly. The reasoning process is not: I assume the Church to be infallible; the Church, being an infallible source, states that it is infallible; therefore I know infallibly that the Church is infallible. Rather, it’s something along these lines:

The Gospels are reliable historical documents. Based on the accounts they contain, it is reasonable to conclude that Jesus is God: He claimed to be God, and backed up his claim with miracles. The Gospels portray Jesus founding a Church. He promised to remain with that Church until the end of time, and to send the Holy Spirit to lead it into all truth. He gave the Church authority to teach and to act in his name. The Church has existed continuously from that time until our own. If that Church has authority to teach in Jesus’ name, and his promise that the Holy Spirit would guide it into all truth, then whatever that Church teaches in his name must be infallible. It’s impossible that Jesus would authorize it to teach in his name if it could teach error; otherwise he would be authorizing the teaching of falsehood, which is impossible.

It is based on this same authority that the Church declares which books constitute the scriptures and are therefore infallible. Thus, we are informed of the infallibility of the scriptures, and of their contents, by a source which is itself infallible.

Now obviously, none of us as individuals is infallible, therefore it’s theoretically possible that Jesus is not God, or even that there is no God. In other words, we could be wrong about those things. We could be deluded or simply misinterpreting the Gospels. Nevertheless it’s a reasonable inference from the available evidence that the Gospels are true; and from there it’s a reasonable inference that the Church is the one founded by Christ and is therefore infallible. From that point it’s a matter of listening to the Church, whom we trust based on our faith in Christ.

I see no similar direct chain of reasoning from the truth of the Gospels as historical documents, to the exclusive infallibility of the 66 books contained in the Protestant canon, when the Church is omitted from the chain.