Fundie Probability: Even Worse Math than Swinburne

I recently got a real prize of a link from one of my readers. He’d enjoyed the [Swinburne][swinburne] article, and had encoutered this monstrosity; an alleged [probability of christianity][prob] argument *significantly worse* than Swinburne.
[swinburne]: “My shredding of Swinburne”
[prob]: “Mathematical Probability that Jesus is the Christ”
The difference between Swinburne and this bozo (who’s name I can’t locate on the site) is that at least Swinburne made *some* attempt to use some math to justify his position. It may have been sloppy as hell – but at least he *did* go through the effort of using actual Bayesian methods. I think that he did an *appallingly* bad job of it; but at least there was something there.
Our new friend doesn’t even bother to do that.
Here’s a very typical example of his “argument”:
>The reason why prophecy is an indication of the divine authorship of the Scriptures, and hence a testimony to the trustworthiness of the Message of the Scriptures, is because of the minute probability of fulfillment.
>Anyone can make predictions. Having those prophecies fulfilled is vastly different. In fact, the more statements made about the future, and the more the detail, then the less likely the precise fulfillment will be.
>For example, what’s the likelihood of a person predicting today the exact city in which the birth of a future leader would take place, well into the 21st century? This is indeed what the prophet Micah did 700 years before the Messiah. Further, what is the likelihood of predicting the precise manner of death that a new, unknown religious leader would experience, a thousand years from now – a manner of death presently unknown, and to remain unknown for hundreds of years? Yet, this is what David did in 1000 B.C.
>Again, what is the likelihood of predicting the specific date of the appearance of some great future leader, hundreds of years in advance? This is what Daniel did, 530 years before Christ.
>If one were to conceive 50 specific prophecies about a person in the future, whom one would never meet, just what’s the likelihood that this person will fulfill all 50 of the predictions? How much less would this likelihood be if 25 of these predictions were about what other people would do to him, and were completely beyond his control?
>For example, how does someone “arrange” to be born in a specific family?
>How does one “arrange” to be born in a specified city, in which their parents don’t actually live? How does one “arrange” their own death – and specifically by crucifixion, with two others, and then “arrange” to have their executioners gamble for His clothing (John 16:19; Psalms 22:18)? How does one “arrange” to be betrayed in advance? How does one “arrange” to have the executioners carry out the regular practice of breaking the legs of the two victims on either side, but not their own? Finally, how does one “arrange” to be God? How does one escape from a grave and appear to people after having been killed?
>Indeed, it may be possible for someone to fake one or two of the Messianic prophecies, but it would be impossible for any one person to arrange and fulfill all of these prophecies.
So the basic method is. Assert that there were prophecies that unambiguously identified a specific event. Further, assert that those prophecies were fulfilled. Now, ask, what’s the probability of all of those prophecies coming true?
The arguments that he presents range from the vague to the silly. In the vague cases, he makes a classic mathematical mistake: switching between a priori and a posteori probabilities. In general, probability calculations are done a priori: “I *don’t know* what specific situation I’m going to apply my calculations to, so when I set the probabilities, I do it without any specific knowledge of a desired outcome”. But he does it a posteori: “Since this description of an event *clearly references* this specific incident, I’m going to set the probabilities using my knowledge of the outcome”.
For example, he asserts things like prophecies naming a specific city in which his alleged messiah would be borne. Of course, the specific prophesy that supposedly makes this claim is not specified. And if you go to other places that babble about the various prophecies about the messiah, you find that none of them are actually *specific*. That is, they all talk in very vague and symbolic terms, and *a posteori* interpretations of those can say that they identify a specific place associated with Jesus; but if you were to read them with an open mind, without any idea of a set of events that you were trying to link them to, you almost certainly would not have demanded that they describe a single, specific location. If they could describe 20 locations, then your probability calculations would need to include the probability for each of those possibilities; if you use the a posteori perspective to narrow it down to one, you’re making invalid use of hindsight to skew the numbers.
Even worse than just using the alleged fulfillment of vague prophecies, he makes an even worse kind of a posteori error: numerous citations of prophecies from the *new* testament: a set of books written *after* the events that were supposedly prophesized – as in the citation of the book of John in the quoted section above. We’re supposed to take the fulfillment of a prophecy that wasn’t written down until *after* the event, and act surprised that there’s exactly one supposedly historical event that matches that prophesy.
Ooh, I’m surprised. A bunch of guys who were trying to convince the world that Jesus was the messiah wrote down prophesies *after the fact* in a way that only Jesus could possibly have fulfilled. Adding *that* to an alleged probability calculation to reduce the probability of anyone but Jesus fulfilling all of the prophecies isn’t even bad math. It’s just plain old lying.
In the category of just plain silly, I absolutely *love* the quote where he’s talking about how hard it would be for anyone else to fulfill these alleged prophecies: “how does one “arrange” to be God?”. Yeah, one of the statements that he supposedly calculuates a probability for is “being God”.
What’s the probability of being God? I’d really like to know. Do I have any real chance of fulling it?
Alas, I can’t tell, Because despite insisting that there are 456 different prophesies that Jesus supposedly fulfilled, and that each of those is factored into the calculuation, he doesn’t tell us how any of those individual probabilities were calculated – for example, he says the probability of an alleged messiah being born in Bethlehem was one in 2.8×105. Where’d that number come from? We don’t know.
And for most of the alleged events that were fulfilled prophesies, he doesn’t even give us that much information.
For example, he says that the odds of fulfilling 48 prophesies – he doesn’t say which 48 – is 1 in 10157. He just asserts that. And then goes off into a classic “big numbers” babble about how terribly unimaginably large that number is. He even goes so far as to pull out one of those bullshit “anything less likely than X is impossible”. (I’m actually playing a game of spider solitaire in the background as a write this; which means that I’m doing something absolutely impossible!)
He’s even got a ripoff of the PSICOP challenge:
>But, of course, there are many more than eight prophecies. In another calculation, Stoner used 48 prophecies (Idem, 109) (even though he could have used Edersheim’s 456), and arrived at the extremely conservative estimate that the probability of 48 prophecies being fulfilled in one person is the incredible number 10^157. In fact, if anybody can find someone, living or dead, other than Jesus, who can fulfill only half of the predictions concerning the Messiah given in the book “Messiah in Both Testaments” by Fred J. Meldau, the Christian Victory Publishing Company is ready to give a ONE thousand dollar reward! As apologist Josh McDowell says, “There are a lot of men in the universities that could use some extra cash!” (Josh McDowell, Evidence that Demands a Verdict, California: Campus Crusade for Christ, 175).
The catch of course is that you need to fulfill the prophesies *in exactly the way that these fundies interpret them* – in other words, starting from the assumption that Jesus fulfilled them, and that the prophecies specifically point at exactly the events of the life of Jesus.
I can actually save the authors a lot of trouble. The probability of anyone else fulfilling these prophesies *is zero*. Because they’re interpreted a posteori as the specific events from the life of Jesus, the odds of it being Jesus who fulfilled them is exactly 100%, and the odds of anyone else doing it are exactly 0%.
Course, if you put it that way, suddenly it doesn’t sound so impressive, even to the bunch of idiots who’d accept this argument to begin with.

0 thoughts on “Fundie Probability: Even Worse Math than Swinburne

  1. plunge

    As far as the Jews are concerned, Jesus didn’t fufill ANY of the actual, pretty darn clear messianic prophecies. We are not in the messianic age. Hence, Jesus ain’t the messiah, folks. World peace? Not quite. Everyone believes in the Jewish God? ah… no. The Temple returned to kingly glory? Nope: in fact, not too long after Jesus, the Temple got DESTROYED. Israel is nation again, but hardly the residing place of all Jews, and that didn’t happen with Christ either.
    The fact that the Gospel writers think Isiah predicted a virgin birth for the messiah (when actually he said that a child would be born to a young woman as a sign to a quite contemporary king’s fortunes, not the messiah at all) and then simply CLAIM that Mary was a virgin in their story doesn’t impress. And the fact that one had him riding in on an ass and its foal, misunderstanding that the prophecy was poetically referring to a single animal, not two, isn’t just unimpressive, it’s risible.

  2. wheatdogg

    There’s a big question whether the early Christians intended to identify Jesus as the Messiah, or whether the mythological framework was added after the four gospels were first written down. For that matter, it’s not clear Jesus himself thought he was the Messiah. From a PR standpoint, if you’re preaching to the Jews about a messiah, you have to somehow equate your man with the messiah prophesied in the OT. My guess is the the mythological stuff was layered on during the years after Jesus’ presumed death and resurrection, until we ended up with the texts we identify now as the Gospels.
    Even now, some Christians look for foreshadowings and prophesies in the OT of Jesus’ birth and messiahship to preach the Word in the NT. I guess it gives their message more impact if they can convince the unbeliever that Jesus was not just some dirt-poor, itinerant carpenter/preacher with dubious parentage, but in fact the savior predicted by the OT prophets.
    Interestingly enough, the people who love picking over the prophesies of Nostradamus do something similar. They say this guy predicted the rise of Hitler and WWII, and all kinds of stuff. It’s all a matter of interpretation and translation, after all.

  3. Mark C. Chu-Carroll

    I’m Jewish, so I definitely agree with you about the fact that a lot of the purported “prophecies” that bozos like this use really aren’t prophecies at all, and that they’re very often based on highly dubious mistranslations. But I try to keep my own religious beliefs out of the blog; they just aren’t relevant. Getting into the arguments about mistranslations and misinterpretations with bozos like the guy whose article I’m fisking just encourages them: it gives them a way of arguing with me without ever addressing the fact that even if you accepted their religious beliefs, the argument that they’re making is just totally bogus.

  4. Orac

    Mark, the website from which you got this idiotic challenge also has a fair amount of Holocaust denial on it (I linked to one of its articles yesterday in my article about Holocaust deniers referring to the “Holohoax). That alone ought to tell you the “quality” of these idiots’ thinking.

  5. theRidger

    While the fulfilled prophecies from the Old Testament are either the product of forcing or cherry-picking, I have to note that the John passage cited was not actually a prophecy. It was a description of events that fulfilled the Psalms prophecy of pierced hands and feet and divided clothing and possessions – his proof of David’s prophetic power.
    Mind you, the dogs and bulls and wild lions of the Psalm don’t make an appearance in John, nor the sword from which the petitioner of the Psalm is saved, but hey. There’s a whole sentence there that fits, so ignore what doesn’t!

  6. Jim Lippard

    This is part of the subject matter of my most popular piece at the Internet Infidels site, “The Fabulous Prophecies of the Messiah.” Peter Stoner’s book _Science Speaks_, referenced by your fundamentalist, is a popular work to cite since it is summarized in Josh McDowell’s classic _Evidence That Demands a Verdict_. I briefly address it in my conclusion, and it’s an amusing book to read–you’ll probably have to use Interlibrary Loan to get a copy. Stoner’s grandson, Don Stoner, wrote me a few years ago to agree with my criticisms (and point out that he’s authored a book for Christians arguing for an old earth).

  7. Barry Leiba

    Hi Mark.

    for example, he says the probability of an alleged messiah being born in Bethlehem was one in 2.8×105. Where’d that number come from? We don’t know.

    To be fair, that actually is one of the bits that’s explained more than the others. If you consider (all estimates here) the world population, the number of population centers, and the population of Bethlehem, and you assume that the birth rate is uniform throughout, you can estimate the probability that when you go to a particular person and say, “Where were you born?”, the answer will be “Bethlehem”.

    It’s bogus, sure, but it actually strikes me as the least ridiculous part of the whole analysis.

    What I can’t figure out is why the guy doesn’t just use the same reasoning to win the Powerball lottery, and live the rest of his silly life in ease.

  8. Mark C. Chu-Carroll

    Hi Barry, good to see you here!
    Unless I’m crazy, the article I linked to didn’t go through the argument about where the probability of the birth location being Bethlehem came from. (Certainly it’s not one of the harder things to come up with some number for; but it’s also one that’s easy to play with to skew it the way you want it to go.)
    I don’t particularly want to go back and look; as Orac pointed out to me, the site that this came from is a Christian holocaust denial organization, and I’d rather not send any hits their way.

  9. MartinM

    Jim: I believe ‘Science Speaks’ is available online. It’s well worth a look. The methodology is quite…interesting. Step one is the same as always: pick a prophecy, and insist it refers to a clear, specific event, and was fulfilled in every detail. Step two, break down the prophecy into parts. Step three is the fun part: ask a panel of college students to estimate the probability of each part. Step four: throw out any estimates you don’t like and replace them with your own invented numbers.
    Now who could argue with that?

  10. sdanielmorgan

    Would you PLEASE PLEASE PLEASE go through the Bayesian formal system that Swinburne purportedly uses and show the errors he makes? I know this may entail having to make a trip to the library for the book, but Swinburne is considered one of the foremost philosophers for theism.
    A serious spanking of his methods would be a more profound post than 100 spankings of stupid preachers using probabilities to “prove” the prophecies are true.
    I run a student freethought group, and I linked to your take-down of Swinburne with the flying monkeys. The professor that serves as an advisor to the group, who is a philosopher of religion, and no friend of theism, came to the defense of Swinburne for being unfairly maligned. He pointed out that Swinburne at least attempts to use Bayesian analysis, so we shouldn’t mock his reasoning as, “it either will or it won’t = 1/2”.
    Read the prof’s comments in the post I linked to you from. Again, I would love to see the breakdown of how Swinburne attempts to formalize his probabilities [rather than arbitrarily assigning them, as others seem eager to do]. A serious smackdown of such a venerated philosopher of theism would be a great resource for the reality-based community, to demonstrate the desperate methods employed by those desperate to defend the premise of their god.

  11. Torbjörn Larsson

    I stopped reading the dunze after ” I’d like share a message from the InterNET by David Williams, Computer Systems Manager, for the Mathematics Faculty, at the University of Newcastle.
    I think you’ll find this edifying. Now remember, David Williams is a mathematician.” It isn’t even Bad Math.
    Mark also said something elsewhere on Swinburne that I don’t see in the commentaries in your post: “If you want to do Bayesian probability, you need to be careful to make sure than your events are independent when you assert that they’re independent; that they’re atomic when you assert that they’re atomic; and that you actually use all of the knowledge available to you to to assess the probability of each event instead of just inserting null hypotheses whenever it’s easier.
    Swinburne didn’t do any of that. He asserted the independence of non-independent things; he used compounds instead of atoms; he use null hypotheses whenever he didn’t feel like actually reasoning about the real probabilities of events; and he just pulled probabilities for other events out of thin air for no reason.
    For you Bayesians out there: I know that Swinburne’s way of pulling the null hypothesis out whenever he’s feeling lazy is not a valid use of Bayesian statistics.”
    My own question is how Swinburne proposes to change his initial assumption of “(1) The probably of God’s existence is one in two. That is, God either exists or doesn’t.” because that is probably what he really wants to do. His conclusion on resurrection can’t help him, because that would be circular bayesian, or as Mark says “you need to be careful to make sure than your events are independent”. His bayesian model doesn’t allow observations. In the absence of updating his belief on the existence of his initial object, how is that belief better than any other default belief on existence of a particular object?

  12. PBH

    I guess I’m just another one of those “fundie bozos” that you all speak of. 🙂
    I do want to say that I do not deny the Holocaust nor do any of the Christians that I know. I think only a minority of Christians would deny what happened.
    Anyway, I stumbled on to your discussion while looking into the info from Stoner’s book. I’m certainly not in a position academically to defend Stoner’s numbers, but admittedly from a Christian perspective it seems as if there is at least some traction that should be conceded in the Messianic prophecies of what Christians refer to as the Old Testament.
    I was wondering if someone could see Jesus in either of the following quotes:
    Isaiah 53
    MarkCC: quotation deleted as spam; you can find Isaiah 53 by google if you want.
    Psalm 22
    MarkCC: quotation deleted as spam; you can find the psalm by google if you want.

  13. Mark C. Chu-Carroll

    I’m not interested in having a discussion about whether or not Christianity is true. I know my opinion on it, and I’ve wasted more than enough of my time on arguing with people who wanted to convince me. I’ve got a couple of simple comments:
    (1) I consider a posting comments consisting of nothing but quotations of huge volumes of some religious text to be spamming. If you’ve got something to say, then say it. Do *not* use my blog as a place to dump huge quantities of your
    proselytizing nonsense. I’m removing the quoted nonsense.
    (2) What do you hope to prove by posting *translations* of some religious text?

  14. Norm Breyfogle

    MCC wrote, “What’s the probability of being God? I’d really like to know. Do I have any real chance of fulling it?”
    This mystic concludes that probability to be 1/1.
    As to Jesus fullfilling prophesy: Just for the sake of argument, let’s say that Jesus was a real historical figure that fullfilled prophesies about the Messiah. I don’t see why someone couldn’t fullfill a large number of the meager amount of such typically vague prophesies by sheer chance and then during his own life recognize this coincidence and come to *believe* that he’s the Messiah … even if he “wasn’t.” This is in fact the implied premise of “The Passover Plot” (a movie based on the book by Hugh Schonfield), which I found to be quite intriquing.
    Of course, to me as a mystic, each and everyone of us is the Messiah whenever we can manage to manifest that archetype … and each and every one of us is already “God.”

  15. Percy Ferry

    The likelihood is that Jesus did not even exist. And all the stories are made up to fit these “prophesies”. I think the probability of that is pretty close to unity.


Leave a Reply