How do we know the meaning of biblical texts?

Edgar Foster, a Jehovah's Witness (JW) wrote to me today, saying that another JW friend of his asked how one can possibly know what the sentence, "I never said you stole money" means. The intent of his question, he said, was to show that just as this sentence is somewhat ambiguous, so the Bible is ambiguous in certain places. How do we arrive at an understanding of what Paul, John or Luke wrote? What follows is Foster's reply to his JW friend (in blue), and my comments (in black):

Foster: One distinctive and prominent characteristic of human language is ambiguity. For example, what if we're sitting down for a meal, and I ask you: "Can you please pass the salt?" How would you interpret the utterance, whether you were right or wrong in how you interpreted it?

Most persons would probably think I was requesting that the salt be passed to me in order that I might season my food. But I could "mean" something totally different by the question. Maybe I meant, "Do you have the power or ability to pick up the salt and give it to me?" However, most will probably not interpret my question as a query about your ability to pick up and pass a salt shaker. The context or situation no doubt helps you to figure out my intent. I think understanding the Bible is similar. Besides God's holy spirit, we can also use "ordinary methods" to discern what Scripture means, including taking the context of ambiguous passages into consideration.

Blosser: I agree that context is utterly crucial to determining meaning, which is inseparably identified with authorial intent. Any number of hypothetical possibilities is possible, as your illustration suggests. The speaker could be insane, or even just trying to confuse you, or even speaking metaphorically, or otherwise cryptically, etc. If the author weren't present, but his words were just being reported to you, it would also be helpful to know somebody you trust who said they knew what the author's intention was.

Foster: The Roman Catholic Church says that the only way we can understand Scripture is by means of ascertaining the authorial intention of the Bible. The only way that we can know what the author of the Bible intended, they say, is by listening to the infallible Magisterium of the Church. However, besides other difficulties that attend this view, I wonder how the Magisterium is able to cut the Gordian knot of ambiguity. Furthermore, as I've asked Catholics before, how can I ever be certain that the Magisterium is infallible or that it is a continuation of the Primitive EKKLHSIA? In other words, how can I ever come to know beyond a peradventure of a doubt that the Church knows what John, Paul or Luke meant when they wrote thus-and-so?

Blosser: Well, here I would say that not only is the context important (which would here include all of history and lower-case "tradition"), but, a fortiori, trust. Because the context doesn't furnish enough information of itself to quite determine the meaning, as conflicting denominational readings demonstrate. Thus having an interpreter whose authority one can trust becomes all-important. Of course one can put this interpreter to the test to a certain extent. But ultimately that testing will run up against limitations, especially where the data furnished by the context is itself contradictory. The case of the underground resistance fighter (Anthony Flew?) is a case in point, because the data of the context seems to contradict his words at times, when he seems a collaborator with the enemy. Or take C.S. Lewis's examples:

"There are times when we can do all that a fellow creature needs if only he will trust us. In getting a dog out of a trap, in extracting a thorn from a child's finger, in teaching a boy to swim or rescuing one who can't, in getting a frightened beginner over a nasty place on a mountain, the one fatal obstacle may be their distrust. We are asking them to trust us in the teeth of their senses, their imagination, and their intelligence.... Wee ask them to accept apparent impossibilities: that moving the paw farther back into the trap is the way to get it out -- that hurting the finger very much more will stop the finger hurting -- that water which is obviously permeable will resist and support the body -- that holding onto the only support within reach is not the way to avoid sinking -- that to go higher and onto a more exposed ledge is the way not to fall." (C.S. Lewis, "The Obstinacy of Belief," The World's Last Night, and other essays, p. 23)

So why do I trust the Catholic Church, especially when there is all this seemingly contrary evidence of corrupt popes, sexually predatory priests, the crusades, the inquisition, the "Donation of Constantine" forgery, thousands of faithless Catholics who apparently don't know the first thing about Christianity? Did I begin by trusting her blindly? No, of course not. I began by discovering several, and then many more, reasons for finding her trustworthy. Answers to the troubling questions became apparent. Many things, even if not everything, began falling into place. The more I "tested" her, digging into Scripture and history, the more answers to such questions became apparent. Is my understanding now complete? Far from it. But I've found for myself sufficient reasons for trusting her, and this conviction is reinforced by the evidence of holiness in the lives of numerous Catholic saints
whose lives are open books, as well as inward truths and movements of God in my own life, which I take to be not only compatible with this trust, but take by faith to be supportive of it. I have no apodictic certitude of the sort Descartes sought. But I have surely as much certitude as I do in my wife's fidelity, or, at times, my own conviction that I am awake and perceive the real world around me.

Foster: Yet, John tells us: "And YOU have an anointing from the holy one; all of YOU have knowledge" (1 Jn 2:20). See also 1 Cor 2:10-12 and 1 Jn 2:26-27; 3:24.

Blosser: Here I would again caution against a reading of New Testament epistles that presupposes the immediatistic, atomistic outlook of contemporary Western individualism found in Protestantism, particularly in Evangelicalism and Fundamentalism. I would caution, in particular, against the assumption that the capitalized "YOU" in the verse you quote above is directed at the contemporary individual reading St. John's letter as part of what we today call "the Bible." In fact, the assumption is easily refutable based on the fact that we know of individuals who have read that passage who would be hard to judge as being among the "anointed" or "holy," or possessed of spiritual "knowledge," such as Joseph Stalin, who is said to have memorized the entire New Testament in his early life.

But as soon as we see this, we note a degree of ambiguity that exists in the question of whom St. John had in mind when he made this declaration. We may say it is those who love God, or those whose lives are "regenerated" by God's Spirit, or the like. But then, how do we know that what we mean by such statements corresponds with what John meant? Certainly not every person who is godly or spiritually wise in his own eyes, or even that of others, can be said to "have knowledge," if is believed by many such individuals contradicts one another.