Jul 06

Biblical Inerrancy is Not Probable

Whenever you attack someone on the inconsistencies in the Bible, they will often retreat to the realm of possibility. But the point I always make is “Why should we care about possibility?” It’s possible that you are reading a blog post typed by a large, green rodent. It’s possible that you will wake up tomorrow only to discover that you’re on a Vogon ship and you forgot your towel. Shouldn’t we instead be concerned with what is likely – with what is probable? With that in mind, let’s consider the issue of biblical inerrancy and discuss probability.

I’d like to be overwhelmingly generous to those who support inerrancy. I’m going to grant you two things:

1. We will say there are only 40 alleged inconsistencies in the whole Bible*

2. We will grant an extremely high probability to each inconsistency and say that there is a 95% probability that a resolution is correct

The way to determine the collective probability (the probability that all of these inconsistencies are merely apparent and would be resolved if we knew the right context, language, etc.) is to multiply the probabilities together. If, for example, you posited two simultaneous events, one with a probability of 50% and another with a probability of 35%, the probability of both together would be 17.5% (0.5 x 0.35 = 0.175). If there were only two inconsistencies in the Bible, each with a probability of 95%, then your collective probability would be 90.25% (0.95 x 0.95 = 0.9025). Are you following me so far? It’s pretty simple, really.

Now for the big question. What is the collective probability, given (1) and (2) above? It is only 12.85%, and that is with my very generous concessions. Conversely, there is over an 87% chance that the position of inerrancy is incorrect. How can that possibly be defended?


*I’ve never actually counted, but this number wasn’t random. I recently saw a book written by an apologist attempting to counter the 40 most popular alleged inconsistencies. So, I think we can assume there are at least 40.

[EDIT: I provided an updated calculation based on a better estimate of the number of alleged contradictions (457) in the bible in the comments. It doesn’t look good for inerrantists – 0.95^457 = 0.00000000660218389726311%]

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  1. Adam Wong

    I’m afraid your rational response will fall on deaf ears once again. You’re not going to change any Christians minds’ with probabilistic analysis. Nice try tough

  2. Mike


    When I think about my goals for this blog, three things come to mind. I want to improve my own arguments and expand my knowledge. That’s been one of the best parts and i’ve found some areas where my own beliefs needed revision. I want to help other non believers to defend against theistic arguments and hopefully provide some good arguments for them to use. And I want to influence those Christians who can be reached.

    So, even if I fail at the last goal, maybe I succeed on the Meatloaf scale of 2 out of 3.

  3. dawkinsassange

    Interesting quantitative analysis. Most skeptics only focus on the qualitative aspects of ancient superstitions. I’ve seen a list of 436 contradictions in the bible, which would lower the odds greatly, even if you reduced your 95% on each contradiction.
    P.S. Love your ‘Meatloaf scale’. Although I believe his scales were a much neglected bathroom apparatus during his heyday.(Fat joke)

  4. Mike

    Thanks, dawkinsassange.

    I have a little update. Havensfire on Reddit pointed me to this link covering 457 inconsistencies in the Bible: http://skepticsannotatedbible.com/contra/by_name.html

    Does anyone care to know what we get if we leave the very high probability of 95% resolution and up the number to resolve to 457?

    0.95^457 = 0.00000000660218389726311%

    Now that is a very small percentage! There is a six billionth of a percent chance that inerrancy is correct, given these numbers.

  5. Ryan


    Rational arguments were precisely what changed my mind when I was a Christian, so it is not a futile effort. And though I recognize that the arguments probably won’t affect the majority, I also recognize that those who can be reached are the ones genuinely worth reaching.

  6. Adrian Urias

    Hey, some questions and comments

    What do you mean by inconsistency and inerrancy?

    Wouldn’t the odds increase if there are multiple resolutions to each alleged inconsistency? If you say “that there is a 95% probability that a resolution is correct”, yet there are five possible solutions to said allegation, then doesn’t that increase the odds of that not actually being a problem?

    Your second concession states that a given solution is more probable than not. But for the sake of argument, lets say it just happens to not be the actual solution. I don’t think it follows the Bible is therefore errant. All we can conclude is, the given solution is not the correct one. We just don’t have the correct solution yet. But as I have said before, this assumes only one solution is possible.

    From this I think we can say that, given your 95%, 95% of the alleged inconsistencies have been solved with the first proposed solution. We then have 5% unresolved. But then if we isolate that 5% (or given 40 alleged inconsistencies, only 2 have been unresolved), and we apply different multiple proposed solutions, each with a 95% chance of success, this makes the solution almost certain.

    Also, and this is more anecdotal, it seems to me that inerrancy is rational. I’ve read the Bible. Sometimes, I don’t think it’s necessary for it to be as long as it is. There are some parts, I don’t really need to know. However, only a fraction of this is allegedly inconsistent. But then, given your 95%, most of this fraction can be easily resolved on the first try. So, if I come across an allegation of inconsistency for which I cannot find a solution, I think it’s safe to assume that there is probably a rational explanation (oh dear, the Christian said “rational explanation”) because all the other ones had one, so it’s probable that these have one as well, even it is not immediately apparent. That’s how I usually explain myself when I come across similar challenges in my evangelism anyways.

    First time visiting the site! cool and interesting stuff!

  7. Mike

    Hi, Adrian. Thanks for visiting. I’m getting ready to head out for a bit, so let me tackle your initial question and then I’ll respond to the rest and get into the “meat” later.

    By inconsistency, I mean an alleged contradiction or something along those lines. A great example would be the genealogy of Jesus between Matthew and Luke. So we have something that we all should admit at least appears to be inconsistent prima facie. Then, someone will introduce a resolution, like that one could be Mary’s genealogy. That’s not conclusive, of course, so we can approach it probabilistically. In this case, I went ahead and granted that all of these had a very high probability for the sake of argument and to make it demonstrable through an actual calculation.

    I would consider inerrancy to at least contain the belief that the Bible does not contradict itself or contain a falsehood. Within that central idea, you probably have literalists who believe in Adam and Eve and the flood and those who think it’s figurative. I was once an inerrantist, but I didn’t believe in the flood, for example. I thought it was a teaching tool, like a parable.

  8. Mike

    Adrian, here are my thoughts on the rest of your comments:

    “Wouldn’t the odds increase if there are multiple resolutions to each alleged inconsistency?”

    Yes, multiple resolutions would increase probability, but not in this case. I am considering the 95% to be capturing that it has a successful resolution. It is actually capturing the sums of the probabilities of the individual resolutions, so your point is already taken into account in the setup. Are you very familiar with Bayes Theorem? If you saw the debate between Bart Ehrman and William Lane Craig, you’ll notice Dr. Craig using Bayes against Ehrman’s critique. That’s the type of probability calculus I’m employing here (but very simplified to make it easily calculable and understandable).

    The above should cover your next few points too. The probability covers all the possible resolutions. It’s not just a first pass at it or the most popular resolution or anything like that. It is every resolution (now, we can’t actually get this number so that’s why I set it very high to be generous).

    On your last point, I would say you are considering them one-by-one. But let’s step back a moment and look at the big picture. That is what I hope to draw out here. The claim of inerrancy is not really just an individual claim. Rather, it is a group of claims that every one of these is resolved (not just can be but really is successfully resolved). So, if we want the best picture of this claim, we actually want to do both things. We want to look at claims individually and we want to look at them as a whole. This post deals with the whole.

    Also, when you think “I resolved the last one in my mind so I’ll probably resolve the next one”, what you’re really doing is a bit different I think. I would say you probably have an assumption going in that it can and should be resolvable. You are working from a framework. I don’t blame you for it; we all do it. But it does affect how you view the initial probability. Consider hearing about Heaven’s Gate – you basically dismiss it out of hand because it doesn’t fit your initial picture. Finally, on that point of inferring, isn’t it still likely that one will come up unresolvable? Think of a free throw shooter with 95% shooting. You think, “he will probably make the next one,” but given enough opportunities, he will fail.

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