Following up on yesterday's rant, which was not really meant to be a rant, and which was not directed at anyone in particular, I want to talk today about expert or scholarly consensus.
While I said in my last post that one should not disagree with experts if one is not qualified to do so, I should give the following caveat: what I was really talking about was expert or scholarly consensus. Individual experts may not be correct. A particular scholar may hold an idiosyncratic, minority, or fringe opinion. Individually, experts are often wrong on particular issues. Yet, there is something called scholarly consensus which non-experts have no ability to judge adequately.
A scholarly consensus is when the vast majority of experts in a given field, with the relevant skills and knowledge, agree that the evidence points to one conclusion. Depending on the field of study, scholarly consensuses can be quite rare. Experts within any given field disagree on plenty of issues. Scholars are not inherently prone to agree with each other. Therefore, when the vast majority in a given field do agree, non-experts ought to respect that scholarly process that led to the consensus. Why these consensuses ought to be trusted is that what is being claimed when a consensus is reached is that, of all of the people with the relevant skills and expertise, looking at the same evidence, the vast majority reach the same conclusion. Scholarly consensuses are hard-fought and contentious matters and are not reached lightly.
Another reason scholarly consensus ought to be trusted by non-experts is because, built in to the very fabric of the scholarly world is a strong motivation to overturn consensus. Most scholars, myself included, want to be respected by one's peers. Because scholars spend their lives thinking and producing ideas, we want those ideas recognized for their merit by other scholars. One of the best ways to gain notoriety and respect in one's field is to successfully challenge a scholarly consensus. If that occurs, what it means is that a particular scholar has gone against the majority opinion of experts, and has been able to convince the vast majority that his or her position is correct. He or she as caused the majority of experts to change their mind. Therefore, there is a built in motivation for scholars to challenge consensuses. And, this does happen. Long-held consensuses are often challenged. Most of these challenges are not successful because the evidence does not support them. But, sometimes they are successful, and the consensus is overturned, a new consensus is formed, and the collective knowledge of experts in the field grows.
Now, let me give a very brief (and surely oversimplified) overview of such a development in my field of synoptic gospel study. The synoptic gospels are the gospels of Matthew, Mark, and Luke, and it has been recognized almost since the birth of Christianity that these gospels bore a special literary relationship. In fact, it was clear as early as Augustine, that these gospel writers had copied portions of their gospels. I often tell my students that if Matthew, Mark, and Luke turned in their gospels to me, I would turn them in to my dean for committing plagiarism. Augustine proposed the following order of composition: Matthew, Mark, Luke (also the canonical order). He also noted that Mark copied portions of Matthew, and Luke copied portions of both Matthew and Mark. This view was held for over 1000 years without any serious contention. Then, in the 1700s a German scholar named Johan Jakob Griesbach argued for a different order of composition: Matthew, Luke, Mark. In his view, Matthew wrote first, Luke copied portions of Matthew, and then Mark condensed both Luke and Matthew into his shorter gospel. This hypothesis, called the Griesbach hypothesis, then won the assent of the majority of scholars for nearly 100 years, thus forming a consensus on what was called "Markan Posteriority" (the view that Mark was the latest gospel of the synoptics). Over the next 100 years or so, several challenges to this consensus were presented in scholarship, and the consensus began to crumble in the 1800s with the works of scholars like Christian Hermann Weiss and Heirnrich Holtzmann. Then through the late 1800s and early 1900s, a new consensus was formed that held a different order: Mark, Matthew, Luke. This is the theory of Markan Priority and this has been the consensus view in New Testament scholarship for about the last 100 years. This consensus has been challenged many times over the past century, but none have succeeded in persuading a large number of scholars. Thus, the consensus of Markan priority is still very much in place in New Testament studies.
So, this example should tell us several things about scholarly consensuses. 1) Scholarly consensuses are not always right. 2) They are often challenged. 3) Some challenges fail and are forgotten. 4) Some challenges succeed and often form a new consensus. 5) Scholarship is always progressing and learning more. 6) Rarely, if ever, do consensuses return to previously overturned majority opinions (i.e., scholarship rarely goes backwards). Once a view is discounted, it is usually not resurrected. 7) Scholarly consensuses fall because other experts with the relevant skills and knowledge challenge them. They do not fall because non-experts do not like certain scholarly conclusions.
All of this is to say that when the vast majority of experts in a field agree on certain conclusions (scholarly consensus), then non-experts ought to trust that they are right, or at least that they are more likely to be right than the non-expert.