Is an Appeal to Consensus an Argument?

Is an Appeal to Consensus an Argument? May 17, 2019

Christoph also wrote:

Perhaps I should indeed stick to writing books not blog post comments since I am apparently not able to communicate effectively in that context.
“Chris, you are surely ripping Carrier’s qualification statement out of context. You have totally disregarded the sentences either side of the one sentence you have addressed and into which you impute thoughts that are contrary to the clearly stated context. In the previous sentences Carrier makes it clear that he does not believe the James in Gal.1:19 is the brother of John — I even quoted that section in my previous comment.”
I know what he says. My point was that if someone writes the conditional clause “if he meant James the Pillar, then he did not mean he was literally the brother of Jesus—as that James appears to have been the brother of John, not Jesus,” he demonstrates that he hasn’t read or is not willing to engage with the relevant literature on the subject. I am sorry for apparently implying something about Carrier’s actual position that I never intended to do.
“If you are basing this assertion on a sentence taken out of context and impute to it a meaning that contradicts Carrier’s clear argument in the sentences either side, then your justification for your assertion is invalid.”

I wholeheartedly agree.

“I have yet to see you give a fallacious example of his estimation of likelihoods. A sentence taken out of context and made to mean the opposite of what the context makes clear he is arguing is not a valid example.”

Is it possible that this is because yourself have a mistaken view of how likelihoods work?
I appreciate the more systematic manner in which you try to apply to theorem to the data here: Still, it’s definitely not correct what you are doing.

“Again, how much have you read of OHJ? Surely it is clear that Carrier does not fall into this “sin” of focusing on numbers and overlooking the real point. He explains quite clearly how the same reasoning can be done without numbers at all.”

Oh, he does again and again. For example, he concludes on Acts that there is at best a likelihood-factor of 0.72 for historicity and it worst 0.2. He then writes: “Conversely, nothing in Acts is unexpected on minimal mythicism, as on that account anything historicizing in it is a mythical invention of Luke’s …, while the omissions and vanishing acts would be inevitable result of there being no historical Jesus.” Here, he’s using “normal” language to say that nothing of that evidence is “unexpected” within the framework of his hypothesis. That’s fine (even though I’d strongly disagree on the individual points). Then he continues: “So the same consequent probabilities on -h can be treated as all 100% across the board.” He adds a footnote, saying that even if not, that doesn’t matter, since the ratio will always be the same. Now, this is surely an absurd claim. I’ve never seen any scholar who works on historical matters using Bayes, who dared to say that P (EIH) = 1! Whether or not some evidence can be “explained” by a hypothesis and whether it is thus “expectable” doesn’t tell us anything about the likelihood. Surely, there are many different ways of writing fiction about Jesus, so even if Luke’s version is the most probable one, it’s still just one among very many possibilities. Again, using θριαμβεύειν in order to refer to the Roman triumph is not “unexpected” in light of the fact that (almost) all its occurrences are used in that way. So a reference to the Roman triumph would “explain” the word choice. But – no – it still doesn’t tell us anything about the likelihoods. Carrier gets that wrong. At almost every point. I used the James example simply because it’s very clear because we are here dealing with a tiny little piece of evidence and not so many assumptions influence the decision (such as how “reliable” Acts is anyway, etc.).

“And again, you have entirely overlooked the key point in Carrier’s argument on this particular point — that Carrier accepts that Galatians 1:19 and James the brother of the Lord must be used as SUPPORT FOR HISTORICITY! So your complaint about him botching the argument by being totally lost in numbers falls by the wayside. He concedes that his argument to the contrary may not be persuasive!”

You don’t have to yell at me. I never said anything else. My point was that even to entertain the thought that perhaps “there is at best no difference in probability and at worst a difference favouring myth” shows that Carrier has clearly not understood how Bayes’s theorem works at all., I don’t care how he incorporates it in the end into his final calculation, what he graciously “admits.” The fact alone that he is able to write such a sentence shows that he has not understood the very basics of Bayesian confirmation. I know this sounds harsh, and if I see how your reactions to my comments have evolved I can see that you are increasingly getting frustrated with me. I’m sorry for that because I see that you also are really interested in the matter – and frustrated with people who just attack Carrier ad hominem. I didn’t want to do that. I just don’t want to interact with him because I am convinced that his argument is deeply flawed beyond redemption.
Let me try to explain with reference to your blogpost, which does a really nice job in translating Bayes into terminology understandable to people not familiar with probability theory. You correctly “translate” the likelihood-factor into the following task: “The next value we need to enter is one to indicate how expected the evidence is if the explanation is true.” Now, what’s the hypothesis and what’s the evidence? You write: “So the explanation, or hypothesis, that I decide to test is: That James, whom Paul meets according to this letter, was a sibling of Jesus. That’s my initial explanation for this verse, or in particular this phrase, ‘James the brother of the Lord’, being there.”
So the situation looks like that: we might have some prior convictions concerning whether in antiquity there existed a person called James (a strange way of rendering the Greek name, by the way, we Germans are much more faithful to the original here ). That includes extra-biblical evidence (ossuary, etc.), evidence from Acts, potential writings by such a person, etc. Then we come to Paul and we encounter the phrase “James the brother of the Lord” (well, it’s a Greek phrase, but we’ll just keep the translation for a moment). So the question is, how this “new” evidence influences the value of our priors, which might differ a lot, to be sure. I don’t want to talk about how the posteriors look in the end and whether Paul’s mention of James actually settles the case. I am not interested in that at all. I just want to look at which hypothesis the evidence favours and how it is doing that – because I believe both you and Carrier are wrong on that.

Let’s look at how you determine the two relevant likelihoods:
“Well, if our hypothesis were true, yes, we would expect someone who met James to inform readers of his letter that the James he met was indeed the brother of Jesus if that’s what “Lord” refers to. (And certainly Jesus is called “Lord” very often elsewhere. So is God, but Jesus is too.) So to that extent the evidence is just what we would expect.“

Good observation. Of course, whether it’s really expected or not will depend to some degree on whether at that point in time there actually were two persons called James in Jerusalem, i.e. it’s only then something we would expect an author to necessarily do if there is reason for confusion (and even then authors sometimes fail to clarify). So I guess you might be a little too optimistic here on behalf of the physical-brother-hypothesis.

“Against this, however, is the problem that if our hypothesis were true — that James, a leader of the church, really was a sibling of Jesus — we would expect to find supporting claims to this effect in the contemporary or near contemporary literature.”

Well, this is an aspect that influences the prior (i.e. updates an earlier prior to the posterior which becomes the new prior). So it’s a fine comment but has nothing to do with determining the likelihood in question here, to be sure. That applies to all the aspects you list in red. Now, don’t get me wrong: these are important aspects to be considered. They might have an immense effect on how the priors of the two competing hypotheses looks like. But if we turn to Gal 1:19 as evidence and what to decide, which one is the best “explanation for this verse, or in particular this phrase, ‘James the brother of the Lord’” we can’t of course take it into account at this stage.

So your conclusion that “we can assign a probability of 0.05 to the expectedness of the evidence that we do have given our hypothesis is true” now actually presupposes that the evidence in question is not what you said in the beginning, i.e. you take an earlier prior in order to show how low the likelihood is. In my opinion, it’s better to focus on tiny bits of evidence and do many rounds of confirmation. Of course it’s possible to take the whole bunch of evidence at once but then you have to be very clear about what the “new” evidence is that is taken into account and what is part of the prior. So in my opinion, if you set out to explain Gal 1:19, you should incorporate all the red evidence you mention as background knowledge into the prior under the heading “So the first value I need to enter is ‘How typical the explanation is’.” In fact, I even believe you have to do so because you use the Gospels’ talk about siblings of Jesus as background knowledge for the prior but then you re-address the same material for the likelihood. That’s confusing it best. Better to concentrate on Gal 1:19, and use the rest for the prior (or write a blog post series in which you incorporate all that background knowledge successively into an original agnostic prior). Again, I am not interested in the posterior here so I’ll just agree with your assessment of all that other evidence. So I think it might be fine to say:
“The prior of the person called ‘James’ in Gal 1:19 being intended to be understood as a physical relative of a person called ‘Jesus’ is 0.05.”
So what’s the likelihood P (“brother of Jesus” I Hypothesis physical relative)? You seem to imply that it is close to 1. From my experience with actual data analysis on similar questions, it’s more like 0.1 or so, i.e. there are just too many factors that might influence an author in not using this phrase even if he or she wanted to make such a reference. Also, there are of course other ways for saying the same thing, such as “brother of Jesus,” “brother of the Messiah,” “the other son of Mary,” etc.
Ok, so let’s assume the prior is so bad. This might mean that even a really good likelihood doesn’t change much, granted. But the likelihood of 0.2 is indeed decent and what we are interested in is which hypothesis is favoured – which has after all nothing to do with which hypothesis has the higher posterior.
Ok, so how does the likelihood compare to the likelihood of the alternative?
You write: ”How expected is the evidence [i.e., the verse Gal 1:19 and more specifically the phrase “brother of the Lord”] if our hypothesis were not true. That is, how expected is our evidence if James were not literally in real life the brother of Jesus?”
Well put. Then you continue you: “Given the considerations listed above, I would say that the evidence is just what we would expect if James were not a literal sibling of Jesus.”
But is it? Apparently you are again thinking of all the evidence that you adduce in red. Again, if you claim to analyse Gal 1:19 as evidence, then this is not allowed and all this has to be used as background knowledge for the prior. So I think what you should have been saying is: “No matter how low the original prior is, all the evidence I’ve adduced above has resulted in an extremely low new prior, with which we now address Gal 1:19.” Alternatively you can, again, of course incorporate all the evidence at once but then please don’t say you are evaluating explanations for Gal 1:19. The reason why I prefer doing it step by step is because it is then clear where the numbers come from. For example: who did you actually incorporate the “brother of the Lord”-reference, the allegedly new evidence that you set out to incorporate? The following statement might work for the evidence as a whole, but certainly not for the “brother of the Lord”-evidence itself: “So how expected is the evidence if our hypothesis were not true? I have to say it is ‘extremely probable’: that is, 0.99.” Of course, Carrier would say that even if you focus on this tiny piece of evidence (as you claim you’d do and as he claims he would do in that section) that’s above right. But he grants that perhaps the likelihood is not 100% but just half as “good” as the alternative likelihood. So if we take the likelihood P (“brother of the Lord” I Physical relative) to be 0.1, the likelihood of P (“brother of the Lord” I Fellow Christian) would be 0.05. It’s difficult to see how you deal with Carrier’s actual assessment because you lump together all the evidence and do not differentiate between different stages of updating (which, again, is fine in principle – but then requires you to specify evidence and explanation differently at the outset). But how does the likelihood really look like?
My most basic point is this: CARRIER DOES NOT ADDUCE THE EVIDENCE THAT IS ABSOLUTELY NECESSARY FOR DETERMINING THE LIKELIHOOD. And neither do you. There’s only one way to find out if you are really interested in statistical values for likelihoods: count how often Paul uses the expression to communicate that thought and count how often he uses other expressions for the same thought. So let’s assume he indeed uses the expression “brother(s) of the Lord” twice in order to communicate the concept of ‘fellow believer.’ Carrier seems to imply that this means the likelihood is high. It doesn’t imply anything of that sort. What we would have to do is to go through the Pauline corpus and watch out for the expressions that Carrier adduces on p. 584 (any many others) in footnote 94. So let’s say Paul refers 100 times in his letters to other Christians and he uses the expression “brother(s) of the lord” twice for that but other options at the 98 other places. That would mean that the likelihood for every individual randomly picked passage would be P (“brother(s) of the Lord” I fellow Christians) = 0.02, i.e. what we would actually expect each and every time Paul makes a reference to such a person is that he uses a different phrase and only in 2% of these cases he will use the phrase “brother(s) of the lord.”
Of course, all these numbers have nothing to do with reality but are only there for illustrative purpose. I don’t care about the actual numbers. And I care even less about the resulting posteriors. What I care about is that you can only come up with a likelihood if you take a look at these alternative ways of expressing the same thought. And Carrier doesn’t do that and you don’t do that and therefore it’s just not possible for you to speak about likelihoods.
Now perhaps you might understand why I found it so outrageous that Carrier at least entertains the possibility that Gal 1:19 might favour mysticism (or is at least not far worse than the physical-brother alternative). The fact that he can manage to entertain such a thought implies that he hasn’t understood how likelihoods work. For if he had understood the conceptof likelihood-rations he would have had to think at least for a second: “The expression ‘brother of the Lord’ is a less obvious choice for a physical relative than it is for the concept of a fellow believer.” And he can’t be serious about that, can he? Of course, saying “brother of X” is quite a default solution for referring to a brother. But on the other hand, even if it’s possible to refer like that to a fellow Christian, it’s certainly not the first choice and he himself never claims so. But without this claim you can’t have a likelihood even being close to favouring mysticism. You just can’t.

“I might be mistaken here, but I think you are implying that because ‘brother of the Lord’ in Galatians 1:19 refers to a physical sibling of Jesus (I agree, and accept your odds of 1000:1 in favour of that being so) that that somehow puts to rest the question of the existence of Jesus. You appear to be overlooking other evidence and problems raised as a result of this passage in Galatians as addressed in the other posts I linked. But those are going beyond Carrier’s argument.
Am I right in thinking that this is the only section of Carrier’s book you have read, and that only partially?”

No to all of that. I just picked this example because I think it’s very clear here to show that Carrier doesn’t understand Bayes at all. In fact, as I said, you might be right about the other evidence and about the priors in light of this evidence but if one claims to do another round of updating one has to do it right. Again: perhaps the posterior will still be worse than for mysticism. I don’t care for this purpose. What I care about is that the updating is done in a way that respects the structures of Bayes’s theorem. And this example demonstrates that Carrier doesn’t do that here. It’s the same at many other places, but here it’s quite obvious. Also, it demonstrates that at a very fundamental level Carrier hasn’t understood Bayes. If you still can’t see that I am sorry because, again, it’s a rather fundamental mistake, something that can happen in a blog post perhaps or happens to students when they are first confronted with the task but which is unacceptable in scholarly literature. If you do understand my concern and you go through the book again, you’ll see that Carrier does exactly this mistake over and over again. But apparently you’ve at least so far made the same mistake. At least your blog post did not show awareness of how the language of “explanation” and “expecting” evidence needs to be translated into an empirical assessment.

And then further:

P.s.: I’d personally evaluate the hypothesis of a gloss in a separate analysis. Again, much will depend on the prior – i.e. how frequent one thinks such glosses are in general and in such situations which this kind of manuscript evidence – but also how probable it is that there was a scribe who felt the necessity to clarify which James was meant and that he was physically related to Jesus. The likelihood for this hypothesis will naturally increase the more specific assumptions we make about the scribe (i.e. we can imagine a scribe who with high probability would render every mention of James into “James, the brother of the Lord”) – which will in turn cause the prior to decrease. Or we can keep the hypothesis more general, which will be good for its prior but would then of course also decrease the likelihood-value (just as Paul had different ways of referring to a potential physical relative, a scrive would also – unless of course we can identify a certain setting where Jesus was always addresses as “Lord,” etc.).

You can read the entire thing, as well as the mythicist side of things that Christoph was trying to engage with, on the blog Vridar.


"At 8:18 in this second video from a service at my church I put together ..."

Genesis and Theology
"You're not a gritty, teenage evangelical until you sing "In Your Eyes" as a metaphor ..."

Genesis and Theology
"Wow, I think you'll like this book we are working on, then! It is interesting ..."

Genesis and Theology
"Peter Gabriel is perhaps my all time favorite solo artist, and the work Genesis did ..."

Genesis and Theology

Browse Our Archives

Follow Us!

TRENDING AT PATHEOS Progressive Christian
What Are Your Thoughts?leave a comment
  • John MacDonald

    Christoph Heilig said:

    To the contrary: my most basic claim defended towards my colleagues was that as soon as you say things like “evidence X confirms hypothesis Y, which is thus the most probable explanation,” etc. you automatically have to follow Bayes’s theorem in updating your subjective beliefs, whether you do so intentionally or not.

    And, I think it should be added that sometimes the more cautionary approach is to say evidence X agrees with hypothesis Y rather than confirms it. For instance, if I remember correctly, in some cases the geocentric model was still better in making predictions than the new heliocentric model when it (the heliocentric model) first came out. And, evidence is certainly better at dis-confirming hypotheses than confirming them.

  • An appeal to consensus is a fallacy if you’re looking to syllogistically guarantee the truth of your conclusion, but an appeal to consensus is still evidence in inducing a conclusion, as is an appeal to authority.

    • John MacDonald

      “New Atheists” tend to vocalize an appeal to consensus fallacy in Religious Studies (which they wouldn’t do in, say, biology or physics), since they view the field of Religious Scholars as hopelessly bias, or inept, or both.

      • That’s pretty convenient. I guess that’s in distinction to all the completely unbiased, perfectly competent scholars in other fields.

        • John MacDonald

          I do think scholars should be subject to the most severe forms of review for quality and accountability reasons, as should the ongoing assessment and evaluation of students be equally rigorous, but common sense says this review should be peer based, not amateurs and scholars who have an ax to grind. You will note that Carrier and Godfrey don’t see their own agenda against religion to be a bias effecting their judgment …

          • arcseconds

            The consequences of a small group of amateurs being the only ones to see the Emperor has no clothes needs to be explored more thoroughly. Such a view entails that not only is mainstream biblical scholarship happening to be exploring a factually incorrect hypothesis, it is doing so in a way that’s very obvious to people unfamiliar with the field.

            OK, so every biblical scholar is a hopeless ideologue. What about the athiest ones like Ehrman or Hoffman? Well, they were Christian once, and they’re not vociferously against Christianity (and occasionally say nice things about it) so they must be some kind of crypto-Christian, or they have lingering fondness for their former religion so they won’t undermine such a fundamental tenet as the existence of Jesus (they will undermine the Ressurrection, the existence of God, the notion of the Trinity even being believed by anyone at the time, etc…).

            (It’s not enough to be an atheist, note: if you’re not against Christianity, you’re under suspicion of being with it)

            Or they somehow need to keep saying “Jesus existed” to keep their jobs.

            What about the rest of the academy? Are classicists all uncritical Christians? Obviously not, I guess they’re all so profoundly incurious that not one of them has ever read literature in a related field, or talked to their collleagues (who in some cases even work in the same department) about their work, or they’re all so polite they don’t want to rock the boat by pointing out biblical scholars are inept and blinkered dogmatists.

            Anyone with even a passing familiarity with academics should realise the unlikeliness of that…

      • arcseconds

        I have a degree of sympathy. If one is ignorant of the field, one doesn’t know that it’s not just Sunday School with a more advanced vocabulary. And even on first blush, it doesn’t necessary look all that healthy either. It’s easy to find examples of biblical scholars working in religiously affiliated institutions, sometimes they even hold religious offices, and well-known figures in the field saying strange stuff (N.T. Wright believing in the dead rising after the crucifixion is often bought up as an example by the more informed at this point).

        To find out that it’s not a form of apologetics masquerading as rigourous academic scholarship, one needs to look closely enough to work out there are also academics working in mainstream institutions, that the journals are pretty much equivalent to mainstream journals in related fields, that there are non-Christians working in the field just fine, and that Christians do not get through their biblical scholarship training with naive ideas about the Bible being a thoroughly reliable, factual account of events intact (if they even thought that in the first place), etc.

  • John MacDonald

    I looked it up on Wikipedia, and it said, not simply (i) appeal to consensus, but more specifically (ii) appeal to authority, if overwhelmingly parties agree on the reliability of an authority in the given context, it forms a valid inductive argument. On this issue, Wikipedia cites:

    Lewiński, Marcin (2008). “Comments on ‘Black box arguments'”. Argumentation. 22 (3): 447–451. doi:10.1007/s10503-008-9095-x.
    Emermen, Frans (2010). Strategic Maneuvering in Argumentative Discourse: Extending the Pragma-dialectical Theory of Argumentation. p. 203. ISBN 978-9027211194.

    In this regard, you can see why mythicist writers need to attack the general credibility of New Testament scholars, because analogously in any other academic discipline, such as biology or physics, appeal to authority is perfectly reasonable.

    • Leigh Sutherland

      Economics is another discipline where appeal to authority is about as useful as a chocolate tea cup.

  • Pedro M Rosario Barbosa

    In my particular case, I am a philosopher who dares intrude in two different fields, Science and Bible Scholarship. That requires from me a certain degree of humility and not pretend that I know more than scientists or scholars. For this reason, consensus matters to me. By this, I don’t claim that consensus is infallible, but if it shifts within a field, most probably is because of self-correcting processes.

    In Science, consensus matters, not only because it lets us know about the beginning of the universe or evolution with a degree of certainty, but because it helps provide useful information for public policy. Whether it is education of evolution, or climate change or GMOs, consensus matters, and should be a guide, along Philosophy and Ethics, to let us know which collective path to take.

    Consensus in Bible Scholarship also matters. Yes, the field has a bit of a problem with many fundamentalists and conservatives who are into confirmation bias. However, when I started to seriously seek information within the field, I have found a lot of very talented, insightful, brilliant historians, literary critics, and archaeologists who take their job very, very seriously (I count you, James, as one of them). However, there are areas in New Testament scholarship that have a majority opinion, but no consensus. Other areas are disputed. When I write any article about the New Testament from a historical standpoint, I am careful to point out where the majority or consensus opinions are, and identify sometimes minority opinions that I find meritorious. Regarding some interpretations of certain texts, I sometimes find myself agreeing more with a minority opinion; yet, in those cases, I try my best to point out that I’m not an expert in the field, and be humble, recognizing that when most scholars agree on something, and I don’t, there is a real chance that I might be wrong. Which, by the way, is the reason why I always re-evaluate my views critically, not something easy to do.

    Consensus matters in any field. The people who know and were formed in it should be valued. That’s why I get upset whenever I hear Robert Price say that he doesn’t care about consensus. I may be wrong, he is a nice guy (at least he appears that way), but that sort of assertion seems to me like a sort of license for him to propose anything he wants. This is something that makes me not trust his work. And now that I am reading him and Carrier more often, I distrust them more every day.

    • John MacDonald


      I have an interest in Philosophy.

      I thought your comment was interesting, so I looked up your bio. You wrote:

      I am a philosopher, specialized on Epistemology and Philosophy of Science. Other subjects of my field I am interested in are Philosophy of History, Philosophy of Mathematics, Ethics (including Business Ethics and Bioethics), Philosophy of Religion, Phenomenology, Philosophy of the Mind, and Analytic Philosophy in general. Other things that I am interested in, but apart from my field, are History and Bible scholarship. I reject most (not all) forms of the so-called “Postmodernist” theories, although, in many cases, I do recognize some of their role in social criticism. However, I don’t consider philosophical doctrines that reject of reason, logic, science, and truth as being serious. I consider anything that goes along the lines of “let’s not follow reason / science / logic because it is another discourse / construction /hermeneutic interpretation / etc.” as a case of charlatanism and a cop-out, a failure to confront serious sound philosophical, scientific, and historical arguments.


      I’m a little unclear about what you mean about hermeneutics and postmodernism? For instance, Derrida will say there will sometimes be undecideability between competing interpretive models due to ambiguity in the evidence and polysemia, but Derrida will definitely say there are things like better and worse interpretations, for instance, regarding what Levinas is up to. Similarly, Deleuze will think he knows the essence of what Foucault is arguing.

      Maybe you could clarify what you think “Post-modernism” means by contrasting it by what you think “modernism” means? How do postmodern thinkers, as you say, “reject reason, logic, science, and truth?”

  • A agree with your point about the consensus of experts, though I limit it to the scientific consensus. I’m frequently frustrated by Creationists who are eager to declare themselves Judge of All Science and reject the consensus of the people who actually understand the information.

    • Nick G

      Yes, just like Jesus mythicists who are eager to declare themselve Judge of All History and reject the consensus of the people who actually understand the information.

      • Leigh Sutherland

        You mistake the difference between consensus of opinion on matters which can be tested and areas of academia that are more open to interpretation, Economics, Social Science and Biblical Scholarship are but three among many.

        • Nick G

          No, I don’t. I am well aware there are considerable differences between scholars who study the historical Jesus and the relevant context. What there is not, is any serious debate about whether there was sucha person – mythicism is the hobby-horse of cranks and narcissists.

  • Nick G

    Your paragraph on consensus is so sound, and so well expressed, that I’ve both bookmarked this page and copied the paragraph to a text file, and expect to use it (with attribution, of course) on numerous future occasions!

  • Ursula L

    Who decides what is consensus?

    Consider Fred Clark’s excellent breakdown of how US Christian theology created a “consensus” in many denominations that slavery was fine – and how that still poisons theology with harmful theological assumptions, such as the divorcing justice in this world from the idea of Christian virtue. A “consensus” formed entirely by white male theologians who were primarily from a culture that engaged in the evil of slave owning and who frequently were slave owners themselves.

    Or the remarkable consensus for centuries that women had no business as theological and clerical leaders, formed entirely by an institution that excluded women from that work, and without the ideas of any women who had made an effort to think about such issues.

    Or the consensus in the first half of the 20th century that eugenics was a legitimate scientific and social pursuit – a consensus that was sharply called into question by the logic of the Holocaust, but which had ongoing harmful social consequences, such as the involuntary sterilization of countless people who were considered “inferior.”

    Once you get out of the world of pure mathematics, numbers on the page without any reference to reality, “consensus” is subject to bias – in the US, it will skew towards white, male, and western European culture.

    If you’re going to make an appeal to consensus, you’d better be sure that it is a genuine consensus of all of society, and not biased in harmful ways by the interests of a minority that is granted the status of authority, to the detriment of others.

    • I should have been clearer – when I referred to consensus, I meant a consensus of experts in a given field. The experts can of course still be wrong, but when they almost all agree, it is much more likely that they are right, or that if they aren’t, that this will be unveiled through ongoing research by those with expertise. I didn’t mean to give the impression that I meant the majority of popular opinion!

      • Ursula L

        I’m entirely aware that you meant a consensus of “experts in the field.”

        My point is not merely that the “experts in the field” may be wrong. My point is that the “experts in the field” might be a group that is defined by discriminatory standards, and that this group may be biased. In fact, the “experts in the field” are likely to be a biased group, as women and minorities were deliberately excluded from access to higher education and inclusion in the group of “experts” for centuries. And the accumulated biases are far from being weeded out of the “consensus of experts in the field.”

        When the group of “experts in the field” in US theology was limited to white men, they came up with hideous theology that justified the oppression of women, and the exploitation of Native Americans in US expansionism and Black people as slaves.

        An appeal to the consensus of “experts in the field” is a variation on any appeal to authority. It can make a valid point, but it also has sharp limitations. And those limitations may not be obvious, if you share the perspective of the group that the “experts” are biased towards. E.g., a straight, white, man might not realize just how badly theology in the US is biased towards the POV of straight, white, men.

        • I had wondered whether you might not indeed be intending to make this point. I think it is certainly true that, among experts, there are biases and lack of representation which impacts the trustworthiness of conclusions drawn. I do not, however, think that the answer is to pretend that the majority of conclusions drawn in the realms of the natural sciences, history, and other areas can merely be dismissed, but to recognize that for all their accomplishments, these are still endeavors by fallible human beings, and while the existing community of experts that provides peer evaluation and critique makes it more likely that the experts will be right than wrong, the likelihood will be even stronger if the biases and lack of representation are addressed.

          • Ursula L

            I think you’re severely underestimating the harm caused by bias. It’s not merely a matter of trustworthiness, its a matter of morality.

            For example in the field of history (I have a BA in European history and a MA in US history) the “consensus” has been one, for decades, that glorified US wars of aggression against Native Americans – at the same time that it recognized that “war of aggression” was, justifiably, one of the charges brought against Nazis in Nuremberg. The consensus among professionally trained historians didn’t see the ethnic cleansing that was part of US expansionism, or its moral implications. Nazi documents that refer to the US treatment of Native Americans and Blacks as a positive example for their own policies are conveniently overlooked.

            In medicine, women were deliberately excluded from clinical trials and studies, resulting in problems that killed people – e.g., heart attack often presents differently in women and men, and doctors were only trained in the symptoms that show in men, so that women are more likely to be misdiagnosed.

            I’ve also pointed out Fred Clark’s (Slacktivist) observations in theology – the group of “experts” in US theology has not absolutely rejected as morally corrupt the work of any past theologian who justified slavery, or to call into question the work of any theologian who would positively cite a previous theologian who justified slavery, leaving the “consensus of experts” in a state of hopeless moral corruption.

            Any appeal to the consensus of experts needs to consider who is allowed to be in the group of “experts,” who is excluded from the group of “experts”, what biases the included group brings to the discussion, and what perspectives are kept out of the consensus-forming process by the exclusions.

          • I agree – although I hope I am not in fact underestimating the harm caused by bias. My concern is that, in the process of responding to these historical inequities that need to be urgently addressed, we not make room for them to be misused as an excuse for evolution-denial, history-denial, and the like.

          • arcseconds

            Do you have a solution for, or at least a way forward on, this that results in the wrong sorts of bias being corrected, but without just opening the doors for anyone who can claim some kind of bias against them to call themselves an expert and demand to be taken seriously?

            Of course I agree with your points by and large, but similar arguments are made for crank science. Young Earth Creationists and Intelligent Design proponents insist that they are systematically excluded from the academy and education due to a dogmatic commitment to naturalism (and it’s certainly true that there is a tremendous bias towards naturalism in science!). People like Mbeki and Foucault have argued that AIDS is not caused by a virus, but rather by malnutrition (Mbeki) or is actually a hoax (Foucault), both can argue that the HIV paradigm has been foisted on to society by an exclusionary group of white straight men. And it’s certainly true the medical community and health authorities are very unrepresentative, as you point out yourself.

            On the history side, Indian nationalists are enthusiastic about rejecting the consensus of scholars that Indo-European languages did not originate in India, in favour of the thesis that they did. Like Native Americans they can point to colonialism and racism as to why their theory is not taken seriously.

            As a side note on your point about theology, I don’t think there’s a theological community in the same sense there is a medical community, rather each faith group has their own theologians. Already we can see a problem here, that the individual communities are quite parochial (almost literally in this case). And it’s massively institutionally biased towards Christianity (I imagine it’s extremely difficult, if not impossible, for a Muslim or an atheist to get a position of Chair in Theology) and technically the term ‘theology’ excludes non-theistic belief systems. To the extent there is a community (they do read outside their faith traditions to some extent, even outside Christianity), there is no consensus.

          • Ursula L

            A few things. Sorry for the delay in my response, I was out of town for work for a while.

            First, you don’t have to be an expert in a field to see bias in a field, and pointing out bias in a field is not the same thing as claiming to be an expert in the field. In fact, recognizing bias in a field is most natural for people outside that field, as they can see when they’re being excluded, while the experts just assume that they’re seeing everything. The identification of bias is a point where the voice of non-experts is particularly important.

            E.g., for a woman to say “I’ve seen a half-dozen women friends die of heart attacks that weren’t diagnosed until too late, because they didn’t have the “right symptoms”, and all of you male doctors and researchers have been using only men in your studies, THIS IS A PROBLEM” is exactly what is needed to identify and address the situation. You don’t have to have the expertise to find the solution in order to identify the problem.

            People die because of the biases of “experts.” The key is to identify those biases, so that they can be addressed, which is often best seen by non-experts, without jumping to the anticipated conclusions of non-experts.

            Regarding theology, while there isn’t a single theological community, there are established theological communities of experts within each Christian denomination, and also within other religions and sub-groups within religions. And once you’ve defined your community, and your experts within your community, you can identify bias. Of particular importance is the denominational breaks that happened in the first half of the 19th century among Christians in the US. A lot of denominations split along North/South lines, meaning non-slave-owning/slave-owning lines. And any moral and theological conclusions drawn by the slave-owning side are utterly and completely morally compromised.

            Even if, say, the Southern Baptists were completely right for the past 150 years about what God has to say about slavery, it doesn’t mean that they are morally right. It merely would mean that God is a moral monster who endorses slavery, and indistinguishable from the Devil.

            Any appeal to authority that points to anyone in a “Southern” theological tradition is inherently morally suspect. If you can be wrong about something as basic as “slavery is bad” you can’t be trusted about any moral issue.

            By contrast, consider the scientific experts on anthropomorphic climate change. The obvious group of experts are meteorologists and others who study the climate and weather directly. And anyone who has done serous study in these fields is in agreement on what is happening. But they aren’t alone. There are other scientists and experts, in other fields and situations, who also see the problem. People who study glaciers. People who study agriculture and plant growth. People who study fish populations, and how water temperature affects fish. People studying insects, and how temperature affects their reproduction and survival. Government officials in nations comprised of small islands, who are directly affected by rising sea levels, and who see the effects directly and are elected to speak for the people most closely effected. Ordinary people, trying to move away from their homes after years of crop failures as the climate no longer supports the growth of foods they rely on. And recognizing that, say, authorities in the US, where we’re big enough to be able to rearrange things to accommodate climate change, are less compelling than the arguments of people in low-lying nations like Indonesia or the Seychelles, who will see their nations disappear as the oceans rise.

            An appeal to authority on climate change is an appeal to multiple authorities, in multiple fields, all of who’s conclusions converge on the same answer.

            And a valid appeal to the consensus of authorities requires a wide field of authorities, and the burden of proof is on the person making an appeal to that authority, to be able to point to a group that is wide and diverse.

            In any situation, if you are making an argument based on the consensus of experts, you’re making an argument based on an appeal to authority. So you need to define your group of authorities, and be prepared to say why you think that your group of authorities are the right ones to be giving definitive answers on the subject.

          • Very nicely put!

  • Realist1234

    In theology the appeal to ‘consensus’ amongst scholars is pretty meaningless given the different groupings – conservative, liberal and all those in between. It’s not exactly like physics, though even there there isnt always consensus – string theory anyone? lol