It should be obvious to all, but unfortunately, it isn't. The doctrine of inerrancy, as formulated by the Princetonians, and as it is understood throughout Church History, has to do with what the Bible is actually teaching versus what it merely uses to teach it.
Unfortunately, in the Enlightenment, we developed a mindset that extracts every detail out from a text and examines it as whether it, all by itself, standing on its own, is true or false, accurate or inaccurate.
Hence, if someone says, "I will search the four corners of the world to find you," one may note that the intent of this statement is to convey the subjects dedication toward finding the object, but he will also extract the phrase "the four corners of the earth" as an individual proposition "there are four corners of the earth," and by doing so reject the statement above as laden with error.
This, of course, is nonsensical. No one believes that the statements of the devil or liars recorded in Scripture are meant to be affirmed, but they are statements that support the linguistic means through which the intended truths are affirmed. As I've argued before here, language is filled with all sorts of imagery, mythology, phenomenology, and inaccuracies. That's because language is not omniscient (because the humans who speak language are not omniscient). That's also why you can never really know what an author really believes apart from his making statements like "there are four corners of the earth" as the intended affirmation in his writings (since he may be constructing that language from his own cosmological thinking or simply borrowing it from others).
No doubt, however, the ancient author may have believed that there were four corners of the earth, but that still does not justify the extraction and conclusion that his statement is erroneous, since it was not his purpose to convey a cosmology here, but only to express his dedication to the object of the sentence.
In other words, if I can use this same language without assuming its literal accuracy, and the ancient author can use it while assuming its literal accuracy, then it is clear that the assumption that functions as a linguistic support to another proposition does not have to be assumed as true or false in order to use it as such.
When we approach something like the Bible, we have something rather unusual as well. We have two authors of every text, not one. We have both a divine and human author. Because of this, the human author may assume all of the linguistic expressions, known to us to be inaccurate, as true if he were to be asked if he believes them as separate propositions. But the same cannot be said of God, who is omniscient. Hence, it must be that God is using the human author's assumptions as language, not as individual statements of truth to be believed.
In fact, this helps us understand that the idea of "what the Bible affirms" is the only logical conclusion one who believes in biblical inspiration can make, since it is only in the affirmation where both God and man could be in agreement. God cannot agree that there are literally four corners of the earth, since He knows that such is not true. The human author can use that language, whether he assumes it to be true or not, in order to convey another truth. Hence, we see that assuming that one does not need to believe that these, what I will call "propositional supports," are literally true or accurate if dissected from the context and made to stand on their own, in order to convey the actual intended proposition of a text itself.
Now, of course, it's a common claim to say, "Well, you have to determine what the affirmation is, and that is dependent upon interpretation." Well, of course, it is. Who ever said it wasn't? But that has nothing to do with inerrancy.
For instance, if we just remove the Bible as a medium for a moment. If we believe that God will not lie to us and knows all things, and that we are about to receive a message from Him, I can say to myself, "Whatever God is going to say is going to be true." That's an a priori statement derived from other a priori beliefs. But I don't even know what He's said yet. That's going to come when I actually hear what He says.
Errancy functions on a priori's as well, but it does not assume that whatever the Bible says is true, since it is the Word of God. It assumes that whatever I believe is true and I have to investigate what is said first in order to determine whether it matches up with what I already believe. The trustworthy part in this case is me, not the Bible. The Bible must be judged to be trustworthy in so far as I have investigated it and considered it such.
So this isn't a matter of one view holding to an a priori (e.g., looking at the box top and trying to figure out the puzzle) and another view holding to a posteriori investigation (e.g., putting the pieces together first and then concluding what to make of it). Instead, it is a difference between a priori belief systems held by the opposing positions.
So investigation, i.e., interpreting the individual passages has nothing to do with the a priori assumptions that each group makes. Both have these assumptions.
Hence, there is nothing off the mark about saying that the Bible is inerrant in all that it affirms before knowing what it affirms. It only seems off the mark for those who use themselves and the zeitgeist (theirs of course, not the zeitgeist of other groups with which they disagree--but that's for another time) as the standard to judge whether all other statements are true.
But as I said, if language can and does use subordinate statements as linguistic clothing in order to express a proposition that is largely independent of that clothing, and can be conveyed in numerous ways with or without it, then the only logical thing to conclude is that truth and error cannot be assigned to the linguistic clothing, since it does not function as separate propositional statements that the author(s) intends to convey on its own.
To give an example of this, I mentioned a few weeks ago Matthew's intertwining in Jesus' words of two Zechariahs found in the Old Testament. Let's say that it was actually a mistake that Matthew made, and he fully believed that the details of the one Zechariah were associated with the other. What the Enlightenment has done to us is to cause us to ask, "Is it true that this Zechariah was killed as the earlier Zechariah, or is this an error?" But we fail to ask the question, "Whether the detail is accurate or inaccurate if extracted from the context, is this Matthew's point?" In other words, regardless of whether these details can stand as separate propositions, they are not the proposition being made. The proposition being made in that text is that the Jewish leaders who are in agreement, in word or deed, with those who committed murder are one with all of the murderers and will be guilty together with them as one group. From that, we might get a more general principle if we see that this is a common proposition attributed to more than just this specific group. And from that generic principle, we might draw an application that if we agree with, rather than condemn, the evil actions of others, we are one with them and guilty together with them of these crimes as a group.
What in the world does that have to do with which Zechariah Matthew is talking about or whether the two are confused? Answer: It doesn't. It has nothing to do with what is affirmed as true. Hence, inerrancy has nothing to do with these details that are not meant to be propositional statements unto themselves.
Now, am I arguing to reject detailed inerrancy? No. I'm saying there is no such thing to begin with. There is no such thing as detailed inerrancy and there is no such thing as detailed errancy. They don't exist, because the speaker/author isn't attempting to investigate or make a conclusion about the details for his audience. He may or may not believe them to be true, but he is not asking his audience to believe them as true in the text, so the text cannot be in error or not in error based upon those details. That is the Enlightenment fallacy committed by errantists and inerrantists alike. This erroneous practice seeks to ask whether something is true of every assumption and subordinate detail found within a text by transforming it from a subordinate detail to a main proposition. In the long history of linguistic and communicative fallacies, that has got to be one of the doozies. It assumes language to be omniscient and if it isn't, rejects what is said. That disrupts communication with finite beings. It does not enhance it. That's why I say to detailed errantists that they are committing a category error and ought to correct themselves and call themselves inerrantists instead.
The only true errantists who exist are those who reject the actual proposition being made as true. They are the ones who deny that everything a given biblical text affirms is true and without error.
Again, this should be obvious to all, but unfortunately, it isn't.