A few readers have indicated to me that my recent series of posts on the problematic use of Bayes Theorem for assessing “historical claims” have failed to make their intended point.
Hopefully here I can succinctly explain why Bayes cannot help us decide whether Christianity began with a historical Jesus.
Reason #1: If our question is simply, Did Jesus Exist? then it is meaningless. What is of interest is the question of how Christianity originated. What might Jesus have done that gave birth to the Christian religion? What did others do during the time of Jesus or after him that shaped or established Christianity? Those are the meaningful questions. Simply saying Jesus did or did not exist is somewhat pointless — unless, perhaps, one wants a negative answer in order to irritate believers.
Reason #2: If by using Bayes one concludes that Jesus “probably did not exist” then again, we have to ask, So what? If it appears unlikely that he existed then after weighing up the probabilities on the basis of the various strands of data, that tells the historian nothing useful at all. Simply saying that Jesus fits the pattern of mythical persons, if that’s where Bayesian inference leads, does not answer the question of whether he existed or not. Simply saying that there is, say, an 80% chance he did not exist still leaves open the possibility that he did exist. So what has been achieved? Nothing useful for the historian at all. Likewise, calculating that there is an 80% chance that he did exist would still leave open the possibility that he did not. The historian is no better off with either result.
I suspect King Philip II of Spain saw the odds of his Spanish Armada crushing the English fleet as overwhelmingly high. The odds against an event happening are irrelevant are irrelevant if they happen. And many times the unexpected and “out of the blue” does happen in history. That they may have been judged to have been unlikely at the time makes no difference to the fact that they happened and are part of the historical record.
Most historical events are “unlikely” or unforeseen until after they happen. After they happen commentators and the rest of us can see how “inevitable” they were. We can always predict what will happen after it happens. Carrier’s mythicist hypothesis can predict the type of evidence the historian will find after the hypothesis was originally formulated on the basis of that evidence. One might look at any number of events in the past and ask, What was the likelihood of X happening? The chances that I will be struck by lightning are very slim indeed. But if I were to be struck by lightning this weekend — stormy weather appears to be approaching — the odds against it happening will mean absolutely nothing against the fact (fingers crossed it won’t be a fact) that it “happened”! Odds against something happening are meaningless when investigating “what did happen”.
We don’t need Bayesian calculations to decide whether there was a Roman empire, or whether its emperors were worshiped as deities, or whether the Roman power destroyed the Jewish temple in 70 CE. The kind of evidence we have for the “raw facts” of the past, including who lived and who did what, are grounded in the same kinds of judgments we make in testing the authenticity of modern claims, whether they be events reported in the news or checking the reliability of advertised claims about a product that interests us. Some of us are less careful with respect to such matters than is healthy and easily believe false claims, present and past. When a historian is interested in whether “new facts” can be dug up to throw new light on a question, it is to the archives, to official records, to diaries and letters and reports of various kinds that they turn. These are tested for authenticity and reliability. If there is doubt about any detail it is more likely to find its way into publication by way of a footnote — with its questionable status clearly noted.
The only justifiable approach to reconstructing Christian origins is to build on the sources we have and on what we know about them — not on what we surmise about them. That approach will not allow us to join in the games of imagining what Jesus and his followers may have done. (We have stories of Jesus and we cannot assume — without justification that would pass the test in any other field of sound empirical inquiry — that they must be based on true events.) We will not have the wealth of details we would like if we avoid make-believe games. But the professional will not apologize for tailoring the question and scope of inquiry to accord with the extent and nature of the source material.
Sure, there is room for Bayesian probability when it comes to drawing certain kinds of inferences from archaeological data or for comparing the likelihood of competing hypotheses, but claiming that so-and-so did or did not exist is by itself a rather meaningless exercise for the reason I stated above.
(See also the section of my earlier post pointing out that not even postmodernist historians work with “what probably happened“.)
To address one specific point I referred to in my recent series: It may well be that one can find in literature more mythical persons who fit a Rank-Raglan hero type, but that is irrelevant to the fact that some historical persons did resurface in later literature wearing Rank-Raglan features (born of a virgin, died on a hill, etc). But even Raglan himself understood that the historicity of a figure was unrelated to the fact that fanciful tales were later told about him or her. If Jesus scores more highly than other historical figures on the R-R scale, so be it: such a “fact” would have no bearing whatever on whether or not he might have been historical. Ask Raglan himself.
Neil Godfrey
Latest posts by Neil Godfrey (see all)
- Is Everything a Question of Probability? - 2024-12-15 03:04:03 GMT+0000
- The Folly of Bayesian Probability in “Doing History” - 2024-12-13 05:51:46 GMT+0000
- Jesus Mythicism and Historical Knowledge, Part 4: Did Jesus Exist? - 2024-11-27 08:20:47 GMT+0000
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I am not a scholar, just a person raised and educated Roman Catholic who developed, in high school, a curiosity about the nuts and bolts of early church history. Research into what objectively is known and objectively can be known eventually led me to the following attitude: Given how deeply Jesus or the Jesus character is embedded in Christian-rooted cultures, I happen to find it immensely interesting to have concluded that we can’t know if Jesus or anyone like the Jesus character actually existed. As to the origins of Christianity, we assume that stories about Jesus or some sort of Jesus character were somehow at the root of what has come down to us as Christianity. The stories could have some degree of historicity or not — it makes no difference in their ability to inspire belief in or appreciation of a wide range of Christianities from fundamentalist to metaphorical or allegorical.
Hermann Detering was a Christian with a _principled_ objection to believing that Jesus was a historical figure. He seems to have felt that Christianity was too noble a belief system to be corrupted by reality (not a quote or even a careful paraphrase).
As another Catholic-raised present-atheist, that’s the kind of Christianity I could join.
Thomas Brodie was another. He likewise held fast to the Christian faith while believing the Jesus story to be a “noble myth” about God’s love.
Agreed. Yes, the question is of public interest and personal relevance to many. The most responsible answer a historian should offer is that we cannot know, that we have no evidence for his existence that is comparable to the kinds of evidence we have for other known historical persons.
The more fruitful historical question is this — if Christianity never existed, what would exist in its place?
For example, would Morality be much different than it is today? Bruno Bauer (the young Hegelian) showed how much New Testament authors owed to Roman Moral philosophers like Seneca the Younger.
John Dominic Crossan, for example, recently posited that a historical Jesus is hardly distinguishable from itinerant Cynic philosophers so common in the Roman Empire.
Even Hegel (1830) had shown Virgin Births, Divine Incarnations, Trinities, and promises of Immortality long before Christianity.
Even the Morality of persecution of gay people long predates Christianity — famous in ancient China and ancient Persia, for example.
What would the world look like WITHOUT Christianity? Nietzsche (“The Antichrist,” 1888) was mistaken, I say, to imagine a utopian world of Roman aristocrats worshipping Dionysus.
A quasi-Christian global civilization existed long before Christianity in Rome, Persia, and much of the ancient world. Monasteries and convents, for example, were unknown in Judaism and first century Christianity — but were centuries old in the Far East and already common in Rome.
As for a historical Jesus — the scholar Morton Smith (not an apologist) did much to recognize the flesh-and-blood figure of Jesus in his book, “Jesus the Magician,” (1977). It does not matter that Magic is superstition — what truly matters is that Magicians were always a historical typus — and everything about Jesus matches that typus.
What made Jesus of Nazareth unique was that he was the first (and perhaps only) Jewish prophet who was also an exorcist — and the first (and perhaps only) exorcist who was also a Jewish prophet. Yet both are recognizable social types from the ancient Levant.
As for the Jewish doctrine of an End Time, a General Resurrection, and a Last Judgment in which the righteous are sent to heaven for an afterlife with angels, while the wicked are sent to hell for an afterlife with demons — all that is much older than the Jewish prophets.
Apocalyptic culture reaches back to the Gathas of Zarathustra, which date before Exilic times (~540 BC; perhaps earlier than ~900 BC, according to some historians).
It is no coincidence that Apocalyptic religion began with the Persian “Farsi” priests and appeared in Judea among “Pharisee” priests only after the Persians had populated Yehud (~540 BC) in Judea.
Nor is it a coincidence that the so-called Apostle Paul was raised as a Pharisee before becoming the most influential of all Christians. Nor is it a coincidence that whole segments of Paul’s Epistles match whole segments of the writings of his contemporary, Seneca the Younger — as demonstrated by Bruno Bauer (1877).
If not Christianity, what? That’s the question historians should ask, in my reading.
No that question isn’t useful for historians either. Counterfactuals aren’t particularly productive in historical analysis because there is simply no way to predict or determine what would have been there instead of Christianity. As Neil points out, you can’t account for so much of history, because so many unlikely and unpredictable things happen. So, these sort of “what if Christianity never existed?” questions are completely pointless except to science fiction and historical fiction authors who want to sell a novel or two. Actual historians shouldn’t waste time on useless hypotheticals that will accomplish literally nothing.
It’s like the philosophical trolley problem (which has been criticized as a semi-useless tool, and non-educational for decades now). A complete waste of time, with no real application or relation to morals in the world, and only exists for college classrooms, so students can meander over a ten page term paper. These kinds of thought experiments are, functionally, useless except as entertainment. Same goes for these counterfactual “what-ifs” of “what if Christianity didn’t exist?” So what? Who cares? It doesn’t change the world we live in, even if you could reasonably answer that question (which you couldn’t).
Re “What might Jesus have done that gave birth to the Christian religion?”
This implies that Jesus was the founder of Christianity and it seems not to be the case.
Point 1: Is Christianity more about Jesus or about Paul?
Point 2: In the book “The Jesus Hoax: How St. Paul’s Cabal Fooled the World for Two Thousand Years” the author, David Skrbina makes the case that Paul created Christianity to undermine the Roman empire and save Judaism. This not outlandish and fits all of the data and also provides a motivation for the spread of Christianity.
Point 3: In the book “After Jesus Before Christianity: A Historical Exploration of the First Two Centuries of Jesus Movements” it is made clear that “Christianity did not exist in that time period. There were so many types of groups one could categorize as Jesus followers, that one has to ask. If the people of that time couldn’t figure out what Christianity was, why would we think we can?
With regard to your point of using Bayes theorem on historical issues (and my experience is almost exclusively from reading Richard Carrier’s works, the objection I had was that Carrier was too generous in providing priors to many of the questions he addressed. Since even with those oh, so generous priors assumed, the probabilities of there being many truths available was still minimal, I guess that is why Carrier did his analyses that way.
And, as far as saying Bayes theorem is not applicable, that is nonsensical. It is a tool, designed to evaluate claims, and using it is no different from using a magnifying glass to see something small.
Re “Simply saying that there is, say, an 80% chance he did not exist still leaves open the possibility that he did exist. So what has been achieved? Nothing useful for the historian at all. Likewise, calculating that there is an 80% chance that he did exist would still leave open the possibility that he did not. The historian is no better off with either result.”
So, his doesn’t even serve as an assessment of the current state of the evidence? You aren’t looking for proof, are you? All historical facts are probabilistic in nature. There is no such thing as proof.
Re “Sure, there is room for Bayesian probability when it comes to drawing certain kinds of inferences from archaeological data or for comparing the likelihood of competing hypotheses, but claiming that so-and-so did or did not exist is by itself a rather meaningless exercise for the reason I stated above.”
So, it is not the use of Bayes’ theorem that is problematical, it is the questions addressed by the researchers? So, why is the title of this piece “The Folly of Bayesian Probability in Doing History”?
This is the first piece of yours I have read, and I have been reading them for a long time, that seems strangely biased.
“So, it is not the use of Bayes’ theorem that is problematical, it is the questions addressed by the researchers? ”
The trouble is that probably all interesting historical questions are too complex for statistical analysis. Mathematics in general, including its half-brother statistics, deal only with idealized and exsanguinated abstractions, and are not applicable to the real world.
That said, Carrier’s book has a lot of interesting content; but it was silly to try to precisely quantify his analysis.
I disagree. There is nothing probabilistic about “the fact” that Japanese aircraft bombed Pearl Harbor in December 1941. There is nothing probabilistic about the fact that Rome once ruled the Mediterranean or that her armies destroyed the Jerusalem temple in 70 CE. Those are known facts empirically established.
I know one hears so often that we can say nothing certain about the past but that claim is confusing two different things. I illustrated these two different things with the way Japan’s attack on Pearl Harbor can be described by historians. The fact of the event is not a probability. What is open to debate are other questions arising from that known and sure fact of history. See my illustration of this point.
Nothing wrong with Bayes as a tool for calculating probabilities. Nothing at all. But what I disagree with is that “doing history” is fundamentally about “probabilities”. Historians study the past events. Those events are on the whole known facts empirically established. They are not, for most part, probability statements.
Historians explore questions arising from those empirically established known and certain events of the past.
I think the fundamental point of difference between your view, Neil, and those who disagree is summed up in these quotes from you:
“Historical events are unique and not subject to probability calculations.”
“The fact of the event is not a probability.”
“Those events are on the whole known facts empirically established.”
Those of us who disagree with you, I think, disagree here. Petr spend a long time explaining the maths, partly I think because the probability does not get to 1. It just doesn’t, that’s not how it works! It also shifts more than you might expect after a few iterations.
Similarly, ALL reasonable claims came to be credible through at least subconscious Bayesian reasoning. So the (maybe subconscious) reason you don’t doubt the Pearl harbour narrative is because you have gone through a process of assessing multiple bits of evidence **in exactly the way RC does for the Jesus example** and the result is very close to, but not actually 1. When people reason validly, that’s what they do. I imagine you disagree with this assertion!
Also to quick point on the lack of multiple ‘rolls of the dice’: it is not the event itself that is repeated, but bits of evidence considered one after the other. Exactly as has been done to establish the Roman Empire and WW1 and Pearl Harbour. There is mountains of ‘expected’ evidence which would be ‘predicted’ on the hypothesis that WW1 happened. All this evidence can be plugged into a Bayesian calculation. There is not some magic, separate process for determining these ‘known’ facts that differs from false or unsure ones.
Is there not a difference between empirically determining that an event happened or a person existed and assessing the probability that an event or person happened? The difference is one of method and conclusion.
Carrier speaks of certain types of information being beyond Bayes — such as knowing for a fact that you are reading these words on a screen right now. But Carrier would have done well to have paused to think through that exception and to ask where the dividing line might be between empirical and probability determinations. He would have had to conclude, I believe, that there is no sliding scale but a difference in types of knowledge and the grounds for different types of “knowing” — that is, two different types of knowledge each in their own buckets. Not a sliding scale.
Our belief that we really are reading these words right now is empirical knowledge, not probability assessments. We are relying on the evidence we can see before us to know, empirically, that we are reading these words. Empirical knowledge extends to what we learn from reading inscriptions on coins or monuments uncovered by archaeologists. There is room for debate over the contents of what we read, but that someone produced those coins and inscriptions is empirically determined and not a question of probability assessment.
Our knowledge or belief that Japan attacked Pearl Harbor does “reach” 1 so there is no room for any doubt at all. The only room for doubt I can see here is if we go all the way and say we cannot know anything, period, such as not even knowing for sure that we are reading these words right now. In that case, literally everything is probable so that probability itself loses its meaning and usefulness as a concept.
We can choose in retrospect to apply Bayesian reasoning to whether the Pearl Harbor attack happened, but that is a theoretical exercise in retrospect and is not the reason we know it happened.
It is the difference between empirically derived information and probability assessments.
But in history we do know that certain events happened in the past and certain actors did such and such, etc. There are no doubts with empirically established information. That Julius Caesar existed and did certain things (conquest of Gaul, reforms in Rome, etc) has no room for probability assessments except in retrospect as a theoretical exercise. We have the independently confirmed and established evidence that leaves no room for doubts as to the basics. The historian does not dispute those. Questions arise over motives, consequences, details but not the core events.
In another discussion thread (Part 2), I have expressed my (vague) future plan to write a summary of my understanding of what is going on here.
Now I just feel like adding a remark on my impression that the basic notions around which the discussion evolves are not clarified; then the discussion can be endless, making not much sense after all.
Instead of Pearl Harbor, let me take the Apollo moon-landing event (that I saw on TV as a boy) as an example, which can hopefully lead towards a clarification of one basic notion.
I voice several assumptions, testing if we all agree on them:
1/ One can create a scenario S in which the Apollo moon-landing event in 1969 did not happen, since it was only faked; we know that such scenarios were indeed suggested.
2/ If such a scenario S is very carefully elaborated then all the evidence that we have cannot really contradict S.
3/ The meaning of the word “impossible” (for the use in this discussion) does not allow us to say “it is impossible that S of the case 2 is true”. We are only justified to say “S is extremely improbable”.
4/ If a scenario S is not impossible but “only” extremely improbable, then the probability that S is true is non-zero (for us, who only have the evidence that we have). This entails that the probability of any scenario S’ that contradicts S is not 1 (for us).
Exactly so — your shift in an illustration for the point of discussion only illustrates my point. Conspiracy theorists jettison empirical testing of ideas and substitute question-begging, confirmation-bias notions. Of course Bayes is great for challenging conspiracy theories. A perfect and valid use of Bayes.
But you cannot apply probabilistic reasoning to the empirically established events of history for reasons I have attempted to explain.
Petr, a constant theme in your responses is, it seems to me, an attempt to explain the process of Bayesian reasoning as new information comes to light. I understand the process and the mathematics used. See, for example, my use of Bayes theorem applied to the question of the “Brother of the Lord” — https://vridar.org/2012/04/22/putting-james-the-brother-of-the-lord-to-a-bayesian-test/
I earlier posted a link to around 50 other posts of mine about Bayes. To keep it simple, here is just one more: https://vridar.org/2011/06/08/bayes-theorem-and-the-jesus-mythicism-historicity-conflict/
I believe I do understand the process. I “believe in Bayes”, you might say — but I do not believe it can be used for one off contingent events that are empirically established. And every known event in history falls into that category. We know Julius Caesar was assassinated by empirical confirmation from the sources. Probabilistic reasoning used to confirm that event and it is not an event that has any smidgen of a degree less than a probability of 1.
My sentence “I voice several assumptions, testing if we all agree on them:” was meant as a yes/no question; let me formulate the question explicitly:
Neil, do you agree with my assumptions 1,2,3, and 4? Yes, or no?
Why do you ask? What are you trying to argue? I agree and acknowledge that Bayes theorem is a valid tool in many situations. Are you trying to convince me to accept what I already accept? Do you understand what my point is? Can you encapsulate in your own words what I am arguing?
Petr — if you are serious about an honest and serious discussion, I implore you, please try, just try, to set out what you believe my argument to be. What is it you think you are trying to argue against? Please … I am really confused by what seems to me to be a wild series of attempts to simply avoid the point I am trying to make. I have asked for this more than once, now, and you seem to refuse point blank. If you continue in your refusal I will begin to think you are a troll.
But if you think it is relevant, here are my responses to each point:
We can imagine anything we like. What is your point and how does it relate to my argument? You asked if I agree with your “assumptions” — I don’t see any “assumption” here, I only see a point blank proposition. What is your point?
So? What does this have to do with empirically establishing an event in reality? Are you really positing a scenario where I have to accept only evidence you allow for a particular mind-game? Αnything can be proved if we make up rules like that. What is your point? Again, you are not presenting an assumption here but rather a point blank proposition.
I don’t know of any scenario that I have encountered arguing for the moon landing being a hoax that leaves anything that is not “contradictable”. Are you trying to tell me that there are water-tight arguments that the moon landing was a hoax and no-one can dispute those arguments? If so, I have to disagree with you.
But this is becoming tiresome. I am beginning to think you have not bothered a moment to try to understand my argument and are only flying off the handle in some misguided attempt to say Bayes is a valid way of reasoning about everything.
Again, what is the assumption you are asking me to agree to? Of course if you set the rules as to what is impossible etc you leave me no choice but to play your game. Now please Petr — I have attempted to understand your point of view so please try to understand mine. What is it that you are arguing against? What is it that you think I believe that you have to prove wrong?
>4/ If a scenario S is not impossible but “only” extremely improbable, then the probability that S is true is non-zero (for us, who only have the evidence that we have). This entails that the probability of any scenario S’ that contradicts S is not 1 (for us).
So what? Do you not understand a word of my argument? Do you know the difference between empirically established event and a probability of an event?
Are you trying to prove to me that the Pearl Harbor bombing “probably happened”? It is your turn to answer my question. Is that what you are saying?
Even though it can’t be proven that Jesus was historical or not, like Robin Hood or King Arthur (once thought to have existed and today carry no weight whatsoever as being historical), maybe by weighing Jesus with the likes of such figures of the Roman, Egyptian, etc. gods we can get rid of the fallacies that now exist within the religions of the world. I welcome all research into such religious matters.
Re: Point 1
There are too many historical possibilities for the origin of Christianity to fit neatly into any framework suitable for statistical analysis: from the inerrancy of the gospels, through Jesus as composite character, to conscious fraud by some Flavian, with many offshoots along the way. I don’t think it’s even clear what the “minimal historical Jesus” would really consist of – e.g. how many red-letter passages in the NT would have to be authentic? 95%, 51%?
As I understand:
a) The core question for historians is not simply whether Jesus existed but rather how Christianity originated. Investigating the actions of Jesus and the subsequent activities of his followers is crucial for understanding the religion’s development.
b) Even if Bayesian analysis suggests a high probability of Jesus’ non-existence (or existence), the outcome remains inconclusive. The historian gains no substantial insight into historical events or the factors that shaped Christianity.
Argument 1:
• Degraded Focus: True historical interest lies in understanding the origins and evolution of Christianity.
• Limited Scope: A simple “yes” or “no” answer to Jesus’ existence provides minimal information about the complex historical processes involved in the religion’s formation.
Argument 2:
• Lack of Practical Application: Regardless of the probability assigned to Jesus’ existence, the historian remains uncertain about the actual historical reality.
• Unhelpful for Historical Reconstruction: Bayesian probabilities, even if seemingly strong, do not provide concrete evidence or insights to guide historical interpretation.
• False Sense of Certainty: The numerical probabilities can create an illusion of certainty that may not accurately reflect the complexities of historical evidence.
Caveat emptor:
“a) The core question . . . Investigating the actions of Jesus and the subsequent activities of his followers…”
To date, however, investigating the actions of Jesus—like the “Jabberwocky” poem by Lewis Carroll—has been one of literature’s epic bits of nonsense 🙂
I don’t think the scholars who do this are engaging in “nonsense”. I think they are genuinely trapped in thinking that they are being objective. The right approach is to try to shed light on the areas where they blur the lines and shapes of what they are investigating. To this end, I see the work of Stephen Young as particularly useful. I posted about his work some years ago but since then he has produced more along the same lines: https://www.academia.edu/73040566/_Lets_Take_the_Text_Seriously_The_Protectionist_Doxa_of_Mainstream_New_Testament_Studies
I am writing about historical methods and historical knowledge because I think not many biblical scholars have thought through these kinds of questions. Even some “nonbiblical” historians tend to sidestep examining face to face their methods. I began my little journey of studying the nature historical knowledge and methods used to build historical knowledge over 20 years ago, initially prompted by the questions raised by Earl Doherty. How do we know anything about the past? Bart Ehrman attempted to answer that question in his published tirade against mythicism but he opined shallow notions from the top of his head and clearly had never taken the trouble to study the question seriously. It’s a serious question and most of what I write, if not everything related to this question, is informed by reading works on the philosophy and methods of historians, past and present.