[Ben Witherington] Q. Mythicists seems to often uses the interpolation theory to explain away NT texts that are inconvenient to their agendas. Yet it is also true that some NT scholars use interpolation theories to the very same end, even when there is apparently no textual basis for the interpolation theory. Explain how the mythicists appeal to interpolation is special pleading, whereas it is not when some NT scholars resort to such a theory (take for example the case of 1 Cor. 14.33b-36, which is displaced in some manuscripts but to my knowledge there are no manuscripts that omit it altogether).

[Bart Ehrman] A. A theory of interpolation argues that there are passages in the New Testament that were not originally there, even though they are still found in all the surviving manuscripts. When a passage (whether several verses, a single verse, or part of a verse) is not found in one or more manuscripts, then the decision whether it was originally in the NT is based on textual criticism. Scholars have to decide then which manuscript(s) more likely presents the oldest form of the text. But when all the manuscripts agree, and one wants to claim that they are all wrong with respect to the oldest form of the text, that involves arguing that at a very, very early stage of the transmission of the text (when it was being copied), someone inserted a verse (or verses, or part of a verse) that came to be found in all our surviving manuscripts. That would be what we mean by an interpolation.

In my opinion, there is no reason, in theory, to deny that there could be interpolations in the New Testament – that is, places where all our manuscripts include a passage (a verse, part of a verse, several verses) that was not originally put there by the authors. This is especially the case in light of the fact that we don’t start getting relatively complete manuscripts of the New Testament until well over a century after the books of the NT were written. At the same time, I think that if someone thinks a passage was an interpolation, there needs to be very, very, very compelling reasons for thinking so.

In almost every instance in which scholars have suggested that there are interpolations, I think the evidence is not compelling. The one instance that I think is compelling is 1 Cor. 14:34-35. I don’t need to give the evidence here. But I find it completely convincing. I should say that whether the verses are original or interpolated does not matter much to me personally. And that’s precisely the problem with many instances of alleged interpolation: it often happens that the scholar who proposes an interpolation has a vested interest in the matter, because if the verses are in fact original, then his or her particular view of things/interpretation is more or less destroyed.

That happens to be the case with the mythicists, as I repeatedly show in my book. Whenever there is a passage that contradicts their views, they invariably claim that the passage is an interpolation. This is what I have called “interpretation by convenience.” If a passage contradicts your view, then the most convenient way to deal with it is by claiming that “originally” in fact it supported your view, but someone came along and changed it. And so, for example, some mythicists “take out” the references to Jesus in Paul, claiming they were not original. And on what grounds? Because Paul doesn’t mention Jesus! That, obviously, is circular reasoning. In any event, I cite a number of instances of this kind of proceeding Did Jesus Exist.

Here let me just say that every case of alleged interpolation needs to be considered carefully and on its own merits. In principle, none should be excluded. But to be accepted, there needs to be a LOT of compelling arguments.