In conjunction with my Critical Thinking course this month, and in light of a number of casual debates I’ve been in lately, I’ve drawn up this twelve step advice, which actually applies to all arguments for any conclusions in any subject whatever. But I’ll use defending the historicity of Jesus as the key example. The first rule is pretty obvious…
1. Tell the truth.
I wish I didn’t have to say that. But it’s apparently necessary to put this front and center, as the most important step. Don’t make things up. Don’t make claims you haven’t checked are true. Don’t make false statements about what any opponent has or hasn’t argued. The truth should not have to be defended with lies.
That you are lying, calls into question the truth of what you are defending. And your motives for defending it. And yet this has happened repeatedly in the historicity debate. Actual sitting professors have lied about the evidence and lied about their mistakes in addressing the evidence (examples include Bart Ehrman, e.g. this lie and this lie and this lie, and James McGrath, e.g. this lie, and all these lies). Amateurs and Christian apologists are even more prone to doing this. Which also means, you need to be on your guard against this. Sadly, you can’t even trust high-profile professors these days. Fact-check everyone.
2. Consensus is a weak argument.
If a peer reviewed study challenges the consensus, citing the consensus against it is literally a fallacy of circular argument. You need to explain why the consensus is correct and the challenge not sufficient to overturn it. “That it’s the consensus” does not answer that. And yet answering that is difficult in a field awash with strong religious biases and no coherent methodology for adjudicating what’s true.
False analogies, like Holocaust and Global Warming and Evolution denial, only make you look dishonest, or totally ignorant of the actual problem in the case of Jesus, for whom nowhere remotely near as much evidence exists as exists for those other things. But more importantly, for all of those things, we can explain why the consensus is right and the challenge to it wrong. And it is only because we can do that, that “it’s the consensus” works as an argument in those cases. So it won’t work in any other case, if you can’t do that. So do it.
A more apt analogy is Moses and the Patriarchs: consensus once held they existed; the mainstream consensus now, is that they didn’t, or that their existence is sufficiently doubtful we can’t affirm they did exist with any honest confidence. If the consensus was wrong about them, it can be wrong about Jesus. So you have to check…
What justifies the consensus? Is it a series of weak evidence and overt fallacies? Or a vast body of superbly clear evidence beyond reasonable dispute? Contrast, for example, the evidence we have for Tiberius, Julius Caesar, Alexander the Great, Socrates, Spartacus, Pontius Pilate, and even Herod Agrippa.
Essential reading on this point is my book Proving History (on the widespread abuse of fallacies in Jesus studies) and my previous article on Arguments from Consensus. The former in turn cites every dedicated peer reviewed study any scholar has made of the methods used in Jesus studies, and every single one found them to be too fallacious or inadequate to establish the conclusions claimed with them. When every study of your methods by multiple experts in your own field finds those methods don’t work, you know “consensus” has become a fallacious argument. Your field is in need of major reform. If you are an expert in the field, do something about that. If you are not, demand experts do something about that.
3. Take logical validity seriously.
You can’t fix your broken methods, or use any method properly, or justify any conclusion you assert, if you don’t even know how to vet an argument for logical validity, if you don’t even know what a fallacy looks like and how to fix or avoid it. You need to learn logic. You need to take learning logic seriously. And you need to apply it to all your reasoning toward any conclusion whatever, including whether Jesus existed. Don’t go around saying your conclusion “feels right.” Figure out why it feels right, and thus whether it feels right for logically valid reasons, or logically invalid ones.
This is another rule I wish I didn’t have to explain to an entire field, a field that sadly is bereft of almost any interest in or knowledge of logic, yet claims to be reaching logical conclusions (see Historians’ Fallacies for a broad survey of this problem). What kind of expert are you claiming to be, if you don’t even know if your conclusions are logical? And you can’t know if they are logical, if you don’t know why they are logical. So you have to master at least basic principles of logic. And apply them in testing and vetting and shoring up your reasoning for any important conclusion.
The failure to do this is most evident in the behavior of Bart Ehrman, who has mocked every demand for logical validity in his own probability reasoning, even mocking the logic of probability theory itself (in his debate with Robert Price, and elsewhere). So far his only response I have ever seen to the numerous fallacies I catalogued in his work on this (just search “fallacy” in my Ehrman Recap article), is to complain about my calling out his fallacies. If you are mocking being called out for fallacious arguments, rather than correcting those fallacious arguments or conceding they are fallacious and abandoning them or proving they aren’t fallacious, you are starting to trend toward becoming a fraud. Historicity, or any other claim about history, or the world and anything in it, should not need to be defended with fallacies. And you should care when it is. (See History as a Science.)
4. Distinguish fact from inference.
Don’t state an inference as if it were a fact; identify it as an inference, and present the facts you are inferring it from and why. Did Paul say he learned the gospel “from those who were in Christ before” him? Is that a fact, or an inference? Do you mean to say, Paul said only that he “received” the gospel, and that you infer he meant “from those who were in Christ before him”? Because then, you need to explain why that inference follows. Because it’s not ever what he actually says. The difference between fact and inference is crucial, and confusing them is one of the key places arguments and reasoning go wrong. Even among experts. Even more often among amateurs.
5. Confirm your inferences aren’t assumptions.
Make sure your inferences follow by valid logic from true facts. Because if you can’t, if you can’t even work out by what rule or from what facts you are inferring your conclusion, then you aren’t reasoning; you’re assuming. And this is dangerous. Assumptions you are making can be the product of biases or desires, or the product of pervasive flaws in a whole field (e.g. something you were told but never checked or questioned, or even something you’ll be socially or professionally punished for questioning). If you can’t even remember where you learned it or why you believe it, it may be that you believe it simply because you needed to, to avoid a consequence you don’t like. It could simply be a hypothesis you made up to escape those consequences. But hypotheses need to be proved true, not assumed true. At the very least you need to be able to justify your conclusion that a hypothesis is probable.
Revisiting the same example from the last point: Paul never says he received anything from “those who were in Christ before him.” To the contrary, he spends an entire chapter to the Galatians swearing up and down and in no uncertain terms that he did not receive it from those who were in Christ before him. He is probably lying; but the significant point is that he had to tell this lie. If all he had to do was say he was preserving the gospel as eyewitnesses delivered it to him, and that they would corroborate that, then he would argue that. But he didn’t.
This is crucial to understanding Paul and his circumstances. If the Galatians were accusing him of not getting the gospel from those who sat at the feet of Jesus, or of not having sat at the feet of Jesus himself and thus not being a real eyewitness, he would have to answer those arguments. He doesn’t. He instead was forced to argue exactly the opposite: that he only received it by revelation; because, his argument makes clear, the Galatians would accept no other answer as confirming him an Apostle. So instead of arguing his revelation is as reliable as having known Jesus in life, his argument assumes the Galatians would accept nothing but revelation as reliable at all; and instead of arguing he honestly got the gospel from eyewitnesses, he has to swear he didn’t. Even lying about it. Why?
Any answer you give to that question must take into account two facts: (1) that Paul’s “I received and delivered” vocabulary is identical in Galatians 1 and 1 Corinthians 15 (see On the Historicity of Jesus, Chapter 11.2); and (2) there is no evidence anywhere in Paul that he ever meant by this “received from those who were in Christ before” him (Chapter 11.6-7); while there is ample evidence Paul meant by this “received by revelation” (Chapter 11.4). Because in the only place he ever says how he received it (which is in Galatians 1), that’s what he says (Element 16, Chapter 4). So why are we inferring a conclusion that is exactly the opposite of the one and only thing Paul says? By what logic does that make sense? On what facts is that warranted?
6. Do not straw-man or ignore opposing arguments.
Actually listen, pay attention, make a real effort to understand why your opponent reaches a conclusion, from what actual facts, by what actual rules of inference. Especially arguments published under peer review in your own field’s literature. Make sure your conclusion survives those arguments. Which requires learning what they are, and understanding the facts and logic they follow from…it requires steel-manning them, not straw-manning them.
You can only refute or defeat an argument by identifying a fallacy in it, or a factually false premise. And you can only do that, if you are correctly describing the logic of the argument and it’s premises. Similarly, you aren’t arguing for your position, if you are ignoring the arguments against it. You can’t honestly claim to be making a warranted case that way. Indeed, it starts to look dishonest, when you claim to be rebutting someone’s arguments, and then ignore in your rebuttal every actual argument they made. In the historicity debate, James McGrath practically makes a career out of doing this. Kristi Winters practically employs no other method.
7. Justify all your assertions about probability.
If you assert something is true, you are asserting it’s probable. And if you are asserting it’s false, you are asserting it’s improbable. So, how probable or improbable do you mean? And why is it that probability and not some other? For example, if you assert something is improbable, what do you mean? How improbable? Very improbable? Extremely improbable? Only slightly improbable? And what does that mean? What range of actual probabilities would you agree constitutes “extremely” or “slightly” improbable? And having clarified that, why are you sure it’s that range of probability, and not some other? What facts (about the case or about the context or about the world) justify your assertion that it’s that probability, and not a probability higher or lower than that?
Amateur Kristi Winters gives us a good example of failing at this, when she mistakes the frequency of real miracle-workers for the frequency of mythical miracle-workers. And thus measured the wrong thing (real miracle workers, instead of the fact that there are vastly more mythical miracle workers than real ones!). And thus came to the fallacious conclusion that Jesus very probably existed, because the only two options are “real miracle worker” and “real man who wasn’t actually a miracle worker,” and “real miracle worker” is extremely improbable, therefore “real man who wasn’t actually a miracle worker” is extremely probable. Thus violating The Law of Excluded Middle, a basic principle of logic. Quite simply, she left out “mythical miracle worker.”
The real question is the relative frequency of “mythical miracle worker” vs. “historical but legendary miracle worker.” Because the frequency of real miracle workers is so small as to vanish from any relevant math. You should ignore it. Instead, you need to find data-sets filled with people most similar to Jesus, and look at how often members of those sets (like Moses) are mythical. When you do that, it doesn’t turn out so well for presuming historicity (see On the Historicity of Jesus, Chapter 6; especially Chapter 6.5).
8. Check your factual assertions.
Back your claims to fact with primary evidence, or with peer reviewed or at least well-vetted scholarship that does; especially if someone tells you a fact isn’t true; most especially if that person is an expert in the subject (or, an eyewitness, or someone otherwise directly experienced or studied in the matter you are debating—as can happen in other subjects you might find yourself debating besides the historicity of Jesus). Because as soon as someone as or more expert than you in the subject tells you a fact you asserted is false, how do you know you are right and they are wrong? You better make sure it’s not the other way around.
McGrath and Ehrman have both failed to fact-check claims to fact they’ve made, in ways that they really should never have (e.g. this, and this, and this, and this), and that evinces a sloppiness and irresponsibility we shouldn’t be seeing from professionals in this debate. So why are we seeing it? Expert or not, you should always stop before defending your position with a factual assertion, and ask yourself, “Wait, do I actually know this is true?” Find out.
9. Be your own best critic.
Most importantly of all, always ask yourself, of every conclusion you reach: How would I know if I’m wrong?
In the historicity debate, we see a lot of failure to self-question, for example in the matter of what Paul meant by “brothers of the Lord.” What if Paul meant baptized Christian? (In other words, just a rank-and-file Christian—ranking below Apostles, those not just cultic Brothers of the Lord, but the brothers actually sent by him as his representatives.) That’s the only kind of Brother of the Lord Paul ever explicitly says there is or ever seems aware of there being (see On the Historicity of Jesus, Element 12, Chapter 4; and Chapter 11.10). So how would you know he didn’t mean that when he used that phrase, but actual biological brothers instead? By reference to what facts in Paul? Or if not facts in Paul, why are facts outside of Paul relevant to interpreting Paul? And then, whichever it is, how logically strong is your inference from those facts? Is it weak and uncertain? Or is it decisive? Why? How do you know?
10. Control for cognitive biases.
Because we are all subject to them all the time (just peruse Wikipedia’s List of Cognitive Biases for a scary start). So if you aren’t controlling for them, it is a certainty that you are corrupting your judgment with them. For example, don’t simply try to prove you’re right. That we know leads too often to verification bias, cherry picking, seeing what you want to see, and other common errors. Instead, learn what we all learned that made science our most reliable source of progress in knowledge: Try to prove you’re wrong. Try as hard and honestly and reliably as you can. And then see if you fail. Because that’s the only way to substantially increase the probability you’re right.
And remember to control for biases even in that. Because if you try to prove yourself wrong by lazy, weak, or inept methods, methods not likely to find out you are wrong if you are, methods that can easily fail at that, then failing to prove yourself wrong is as weak and unreliable as trying to prove yourself right and ignoring all falsification tests. To the contrary, trying to prove yourself wrong and failing, increases the probability of your being right only in direct proportion to how effectively you tried. The most robust and challenging efforts to prove yourself wrong (and then failing to do so), produce the most robust and certain conclusions that you are right.
This is actually what happened to me. I was a staunch defender of historicity, dismissing challenges to it as crank and poorly researched and even more poorly argued. But then I read a still-imperfect but nevertheless well-researched, well-argued challenge (which I discussed in my Review of Doherty) and realized the consensus had never dealt with that particular challenge before, leaving me uncertain which would survive any straight-up debate. When my fans funded a post-doc research grant for me to investigate the issue under peer review, my singular goal was to prove my doubts wrong, to do everything in my power to confirm historicity holds up after all. And I tried. For six years. Uncovering every item of evidence. Looking for every argument. And the more I tried to refute the mythicist thesis, the more I failed. I even found historicity becoming less and less credible the further I tried confirming it. Historicity defenders need to engage as serious an effort to prove themselves wrong. Before they can declare any confidence they’re right.
11. Take seriously the likelihoods of the evidence.
Of the best competing hypothesis to your own, ask: If it’s true, is the evidence we have, what we would more or less expect? Why not? Are you sure? Is there any reason that some evidence you would expect to exist, wouldn’t exist? For example, is it probable it would have been destroyed or doctored out of the record, or that any document that would have contained it wasn’t preserved at all? (See On the Historicity of Jesus, Element 22, Chapter 4; and Chapters 8.12 and 11.1.)
Then of course ask the same questions of your own theory. How likely would the evidence that’s missing, actually be missing, indeed wholly gone, unquoted, and unmentioned? Such as all the odd ways Paul’s letters discuss Jesus, all the things missing, all the things no one ever asks him about and never argues with him (see OHJ, Ch. 11). Such as why later Christians had to doctor the Ascension of Isaiah to convert it into a historicist gospel (OHJ, Ch. 3.1). Why they had to forge 2 Peter to answer Christian mythicists (OHJ, Ch. 8.12). Why Papias knows so little about the first century of the church, and everything he claims to know appears to be wildly wrong (OHJ, Ch. 8.7). Why there are no actual letters or memoirs about Jesus by anyone who knew him, but only fabulous myths written a lifetime later (OHJ, Chs. 10 and 11.1; and Element 22, Ch. 4; and Ch. 6.7). Why all the histories that would have covered Jesus, apparently didn’t, even when they should have—like Pliny the Elder’s account of Nero’s scapegoating, supposedly the Christians, for the burning of Rome. Even though Pliny was an eyewitness to those events…so how could he have then failed to give an account of Christians and their origin, or no one have ever noticed he did? (OHJ, Ch. 8.3) And so on.
12. Take seriously the prior probabilities.
First you must distinguish doing those two things (taking seriously the likelihood of all the evidence on your own theory, and likewise when you assume the competing theory is true), from arguing a theory has a low or high prior probability. Why should historicity have a high prior? Or why should myth have a low one? On what past cases or background evidence are you deriving your expected frequency from? And if your sample is small, how do you know what you have is a reliable frequency? (Since the smaller the sample, the higher the odds any frequency you observe is an anomaly.) Mythical persons, it turns out, are more common in some sets, sets to which Jesus belongs.
There is a lot more to grasp about the proper logic of probability, when attempting to argue validly that any theory is probably true, or probably false. You can’t do either, by ignoring that logic. And that logic always requires doing a decent job of asking what the relative priors are, and what the relative likelihoods are. There is literally no other way to do it, if you want a probability (or improbability) to be your conclusion. (See If You Learn Nothing Else, We Are All Bayesians, and What Is Bayes’ Theorem.)
Now take those twelve points, and apply them to every other debate and argument you ever get into. Not just the Historicity of Jesus. But everything else. Feminism. Politics. Energy policy. Medicine. American history. Video game criticism. Literally everything. Those twelve principles, if you follow all of them every time, will make you a much better critical thinker and much less prone to defending and believing false things, and make the things you do believe far more likely to be true. And that’s what it means to be a competent skeptic.