One way that some mythicists have gotten around the problem that this, our earliest Christian source, refers to the historical Jesus in several places is by claiming that these references to Jesus were not originally in Paul's writings but were inserted by later Christian scribes who wanted to think that he referred to the historical Jesus. This approach to Paul can be thought of as historical research based on the principle of convenience. If historical evidence proves inconsistent to one's views, then simply claim that the evidence does not exist, and suddenly you're right.Bart Ehrman, Did Jesus Exist? p.118.
I am sometimes accused of proposing interpolations of convenience when I suggest the possibility that maybe Paul did not write "I saw none of the other apostles—only James, the Lord’s brother." Gal. 1:19. Maybe he only wrote "I saw none of the other apostles—only James." Maybe some later scribe inserted "the Lord's brother" because he thought readers might be confused about which James it was that Paul met. For that matter, maybe Paul only wrote "I saw none of the other apostles." Maybe the insertion of "only James, the Lord’s brother" was the result of some theological turf war where a member of some James faction was trying to make him equal to Peter by putting him at those first meetings with Paul. Given the 150 year gap between the composition of Galatians and the earliest surviving manuscripts, there are no doubt many interpolations that didn't leave any evidence in the manuscript tradition and whose motivations we might not recognize. What if this is one of them?
In a discussion over at Exploring our Matrix, one comment seemed to sum up the the anti-interpolation viewpoint pretty well:
I also have a real problem with people reading in interpolations wherever it's convenient for their theory (rather than on textual critcal evidence), as it makes their theories unfalsifiable. And if they are unfalsifiable, are they really acceptable theories?This seems like a perfectly reasonable position, i.e., absent evidence to the contrary, why not presume that the text we have is what the author originally wrote? But like so many arguments in this field, it can be turned around:
In the absence of the original autograph, could you prove that any passage in any classical text isn't an interpolation? If you think there's a gap between Paul and our earliest extant copy of his letters, think about how big that gap is for other classical authors: it's well over 1,000 years for Herodotus, I think.
Given that we can't prove that any passage isn't an interpolation, why would we treat any text as any more than an approximation of the original, i.e., our best guess? Why would we claim any more certainty about a passage being original than is warranted by the gap between the original and the earliest manuscripts? Why would we propose any theory that was not robust enough to withstand the possibility of interpolations? If we can't prove that any passage is original even where our manuscripts agree, how can we adopt the presumption that it is, even if that presumption is rebuttable? Isn't it more logical to adjust the conclusions we draw to the appropriate level of certainty?
The objection that is raised to answering yes to any of these questions is that it puts us on a slippery slope to a place where nothing is certain, but I think that this is overblown. First off, if we can reliably date the earliest extant manuscripts to the end of the second century, then we can reliably say what the church at that time understood Paul to be saying. Admittedly, that is not nearly as satisfying as thinking we know what Paul actually said, but it's still valuable. Second off, we can develop positive reasons for thinking that a particular word or passage does go back farther. In Paul's case, we can look for ideas that are expressed consistently in several places in several letters or ideas that fit well with his overall themes and concerns. One of the reasons historians always look for corroboration from multiple sources is because any single piece of evidence could be wrong or mistaken. The more evidence you have bearing on a point, the stronger the conclusion.
Moreover, I do not think that this would necessarily open the door to just any old interpolation based argument. The probability of any argument being correct is still going to decrease as the number of proposed interpolations increases. If someone needs eight cherry picked interpolations to support a particular hypothesis, the odds are going to be pretty small that it is correct. (One of the reasons that I remain agnostic about a historical Jesus is that it does seem to me that mythicists are frequently guilty of this.) On the other hand, if positing a single interpolation would dramatically change our overall understanding of the text, then perhaps our understanding is too fragile. Perhaps we shouldn't be proposing any interpretation of the text that would be vulnerable to an interpolation or two.
I often see it claimed that allowing for more interpolation based arguments would throw all ancient texts into question, but I don't see that either. With texts like Plato and Aristotle, we don't worry as much about the autographs. What matters is what has come down to us as Plato and Aristotle and the influence those ideas have had on western thought throughout the ages. Very little depends on whether any specific word or passage came from the actual pen of the author to whom it is attributed. With texts like Herodotus, everything he writes is taken with the appropriate grain of salt anyway. Historians are always looking for corroboration from other ancient writings or from archaeology. In the reading I have done, historians of the ancient world don't seem to claim significant degrees of certainty on the kind of issues that depend on a single passage being the original writing of an ancient author.
It is only with the Bible that it becomes important to assert that we have the originals. If you believe that God inspired certain men to deliver his inerrant truths to the world, then it is very important to be able to say whether the specific words were written by those specific men. If someone unknown philosopher reworked a passage twenty-five years after Plato died in order to insert his own ideas, those ideas hold the exact same significance in the development of western thought as if Plato wrote them himself. However, if someone reworked a passage in Galatians twenty-five years after Paul died, the ideas lose any authority they had by virtue of inspiration. We cannot know that the changes were sanctioned by the Holy Spirit.
I suspect that the presumption in favor of originality is ultimately driven by concerns that are more theological than historical. To many of the scholars working with the texts of the New Testament, it is very important to have some method that enables them to determine the original words of the New Testament because the original words have theological authority. It is not enough for these scholars to determine the words of the earliest extant manuscripts. Therefore they have adopted a presumption in favor of originality based on the earliest manuscripts that is not logically justified. It seems to me that this is scholarship of convenience.
For Ehrman the agnostic, the words don't carry any extra-historical authority by virtue of being written by Paul in 50 A.D rather than inserted by some unknown scribe in 125 A.D. Nevertheless, even a secular historian can draw much stronger conclusions if he knows that he has the words of an early witness to events so it would be nice to think we can know that we do. However, as Ehrman clearly seemed to understand in his 2008 debate with Dan Wallace, wanting to know what Paul wrote and knowing what he wrote are two different things.
Can we trust that the copies of Galatians we have are the original copies. No. We don’t know. How could we possibly know? Our earliest copy of Galatians is p46 which dates from the year 200. Paul wrote this letter in the 50’s. The first copy that we have is 150 years later. Changes were made all along the line before this first copy was made. How can we possibly know that in fact it is exactly as Paul wrote it. Is it possible that somebody along the line inserted a verse? Yes. Is it possible that someone took out a verse? Yes. Is it possible that somebody changed a lot of the words? Yes. Is it possible that the later copies were made from one of the worst of the early copies? Yes. It’s possible. We don’t know.
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What I have said to my colleagues is that we are as close as we can hope to be to what we might imagine as the earliest text. What I have said in popular audiences is we don’t know if we can get back to the original text. And I stand by both statements. We don’t know what Paul originally wrote to the Galatians, and we no hope of getting any closer in the future than we are already now. We have no evidence that can get us any further back than we have already gotten and our earliest evidence is from the year 200, 150 years later. So can we know for certain? No. We can’t know for certain that the text is reliable. You might want to think it is. You might want to hope it is. You might want to say there are intelligent people who say it is so probably it is. But think about it. There are people copying these texts year after year, decade after decade.