Percy and sola scripturaWalker Percy, in The Message in the Bottle, gives what seems to me to be the best argument against sola scriptura that I've ever heard. First, he distinguishes between two types of statements, knowledge and news.
Knowledge is information that can be verified by the reader sub species aeternitatis, It that can be arrived at by anyone, anywhere, any time. For example, "lead melts at 330 degrees." Or "Man is a rational animal."
News is “A synthetic sentence expressing a contingent and nonrecurring event or state of affairs which event or state of affairs is peculiarly relevant to the concrete predicament of the hearer of the news.” For example, “There is a war party coming from a neighboring island.”
Next, Percy points out that the canon for acceptance of news are a) the relevance of the information for the predicament of the hearer and b) the credentials (trustworthiness) of the newsbearer. Then he states that:
The message in the bottle, then, is not sufficient credential in itself as a piece of news. It is sufficient credential in itself as a piece of knowledge, for the scientist has only to test it and does not care who wrote it or whether the writer was sober or in good faith. But a piece of news requires that there be a newsbearer. The sentence written on a piece of paper in the bottle is sufficient if it is a piece of knowledge, but it is hardly sufficient if it is a piece of news.
Clearly, if what the Bible presents us is good news, it not only has to be relevant to our predicament, but it has to be given to us by trustworthy newsbearers. And one cannot determine their trustworthiness from the text of the Bible itself! How do we know that the Apostles are trustworthy? Their trustworthiness is attested to by.......?
Note: In At the Origin of the Christian Claim, Luigi Giussani makes the point the the Apostles are more trustworthy, not less, because they knew Jesus personally.