# Good Math/Bad Math

## Friday, April 21, 2006

### Mind-numbingly stupid math

An alert reader just forwarded me a link to this mind-bogglingly stupid article. This is one of the dumbest pseudo-mathematical arguments that I've ever seen - and that's a mighty strong statement. This Oxford University Professor! argues that he can mathematically prove the resurrection of Jesus. Get a load of this:
This stunning conclusion was made based on a series of complex calculations grounded in the following logic:
(1) The probably of God's existence is one in two. That is, God either exists or doesn't.
(2) The probability that God became incarnate, that is embodied in human form, is also one in two.
(3) The evidence for God's existence is an argument for the resurrection.
(4) The chance of Christ's resurrection not being reported by the gospels has a probability of one in 10.
(5) Considering all these factors together, there is a one in 1,000 chance that the resurrection is not true.

Where to start with shredding this? Is it even worth the effort?

By a similar argument, I can say that probability of pink winged monkeys flying out of my butt is one in two: that is, either they will fly out of my butt, or they won't. The probability that those monkeys will fly to the home of this Oxford professor and pelt it with their feces is one in two. If pink winged monkeys fly out of my butt, that's an argument for the likelyhood of a fecal attack on his home by flying pink monkeys.

Do I really need to continue this? I don't think so; I'd better go stock up on monkey food in my bathroom.

• The probably of each detail of the bible being true is equal to 1/2, it's either true or it isn't. In order for the bible to be inerrant, all details must be true. Therefore, the probability of an inerrant bible is (1/2)^d where d is the total number of details. Because there are more than 10 details presented in the bible, I can conlude that there is a less than 1/1000 chance that the bible is inerrant.

Wow, this new brand of probability is fun!

By  Tiax, at 4:06 PM

• Definitely a lot easier than the probability stuff we learned in statistics. Move over, Bayesian probability.

By  Thomas Winwood, at 4:39 PM

• so, what you're saying is that there is a 75 % chance that the monkeys will NOT pelt his house with feces. Those are alright odds.

By  Anonymous, at 5:01 PM

• That's criminal. I imagine that the math professors at Oxford are hanging their collective heads in shame over this idiocy.

By  ArtK, at 5:57 PM

• [stupid]Maybe you should read his book before you are so quick to critize[/stupid].
Seriously, such a gross misuse of math should be a flogging offense. The guy obviously hasn't the slightest clue about probability.

By  JP, at 6:42 PM

• The sheer stupidity of this schlemihl's "reasoning" both boggles and depresses me. I have tried to think of a statement in another field which would be analagously stupid. It's hard. What could possibly mimic this level of brazen, self-assured ignorance?

The best comparison I can think of so far is to say that this argument is the mathematical equivalent of saying Jesus came from Alabama.

Here's the bloke's Wikipedia article:

http://en.wikipedia.org/wiki/Richard_Swinburne

Maybe this is all a put-up job. Maybe Swinburne wanted to see just how awful a theology book could be and still get published, so he got Alan Sokal to write up the dumbest math possible.

Or maybe Swinburne lifted the pseudo-mathematics from Chuck Klosterman's Sex, Drugs, and Cocoa Puffs: A Low Culture Manifesto. I happened to see this book on a friend's coffee table, and I flipped through it (neither my friend nor I bothered to finish it). Klosterman gave the same reasoning that all probabilities are 0.5; moreover, he did it with such arrogant prose that I felt directly insulted.

In my most humble and pacifist opinion, people who talk like this should be told that there is a fifty-fifty chance their toenails will be ripped off tomorrow. Either it will happen, or it won't. And I thought I was such a nice guy. . . .

By  Blake Stacey, at 7:28 PM

• Some quick Googling reveals that this is not a new argument. According to
this review, it appeared in Swinburne's The Resurrection of God Incarnate (Oxford UP: 2003). It was just as hopelessly flawed then as it is now, of course. Drawing out the illogic to book length pulls a little wool over the essential fallacies but does not eliminate them.

It looks like this Netscape/CNN article only came out on 20 April 2006. At least, that's the date which shows up in the Google hit-list. A three-year delay for news of this momentous import? Gosh, I knew journalists had problems, but that's just ridiculous.

By  Blake Stacey, at 7:51 PM

• blake:

I have to say that I agree with you. I originally tried to come up with some kind of metaphor for how stupid it was; the pink flying monkeys was the result of my giving up in disgust. There's just *no* serious argument that can possibly compare to it; and the moment you translate it into anything but religion, it's just so over-the-top ridiculously foolish that the flying monkeys are more credible.

By  MarkCC, at 7:54 PM

• blake:

I'm even more shocked and appalled. I assumed, from the Netscape article that I was sent, that this was a relatively small part of this, uhh.. gentleman's book. The idea that the Oxford University Press would publish a *full textbook* centered on this utter wretched dreck...

Seems to me, this is pretty much evidence that there isn't a god, because if there was, he'd make the earth open up and swallow this guy before he could make religion any more embarassing.

By  MarkCC, at 7:59 PM

• Now that I think about it, the chances of the ressurection being not true -clearly- aren't 1/1000. Its either true or its not. Thus, 1/2.

QED

By  Tiax, at 9:08 PM

• "Now that I think about it, the chances of the ressurection being not true -clearly- aren't 1/1000. Its either true or its not. Thus, 1/2."

Holy crap! That means that 1/2 EQUALS 1/1000!!!!!!!

By  Anonymous, at 10:33 PM

• I'm the tipster. I'm glad you chose to comment on the story. I made a meta post on my site. My complex calculations prove there's a 50% chance you'll click the link.

By  Mike, at 12:24 AM

• Astonishing, Mike. I scrolled past your comment twice. First time I didn't click; second time I did. One in two chance!

By  Thomas Winwood, at 2:16 AM

• Excellent. Another person to add to my "must play at poker" list.

By  Rachel Walmsley, at 2:45 AM

• To be fair, his argument is not the ridiculously stupid "we don't know whether God exists or not, so the probability is 1/2". Swinburne thinks there are independent theological arguments (from design, etc) that make the existence of God likely; he then picks 1/2 as a "conservative" estimate. The number 1/2 for the probability of Incarnation is arrived to in a similar way.

The problem is, of course, that an atheist would find all the probabilities he assigns hugely inflated. But it's not that he does not argue for them; it's just that his arguments for them are unconvincing. They have to be examined step by step.

The logical form of the argument, by itself, is not fallacious. It's a bit like using Drake's equation to prove that there are millions of extra-terrestrial civilizations; the equation itself is correct, but one can dispute each assignement of probability separately.

By  Alejandro, at 8:26 AM

• Maybe Swinburne's argument is more sophisticated. But there's no getting around that the article argues that way:

"The probably of God's existence is one in two. ___That is, God either exists or doesn't.____"

By  Anonymous, at 11:42 PM

• When playing a hand of poker you either win or you don't. So each player has a 50% chance of winning each hand. I'm heading to Vegas on the next plane.

The plane will crash or it won't.

I'm staying home.

By  Don Sheffler, at 12:46 PM

• Swinburne has been at this a while: he used a similar method in his 1979 "The existence of God" at least, and probably in several of his other works as well.

In that book, he ran through all the old long-refuted proofs of God's existence. He admitted that each fails to prove God's existence. But don't go praising his intellectual honesty just yet.

Because he then turns to some fancified figgerin' -- "confirmation theory", he calls it -- and throwing Bayes around like a beachball he reaches a remarkable conclusion: although each proof is individually invalid, collectively they present us with overwhelming evidence for the existence of God.

Or this is roughly my recollection. I was half-impressed at what is, as far as I know, a new proof of the existence of God; and half-flabbergasted that such crap ever gets said with a straight face, never mind published.

By  bcarson, at 10:29 AM

• Because he then turns to some fancified figgerin' -- "confirmation theory", he calls it -- and throwing Bayes around like a beachball he reaches a remarkable conclusion: although each proof is individually invalid, collectively they present us with overwhelming evidence for the existence of God.

OK, I can see how that would go. See, if you have a bad proof for something, that doesn't actually mean that the thing you're trying to prove is false - sort of like "absence of evidence is not evidence of absence". Hence, for every bad proof you present for God's, there's a small chance of God existing regardless.

Now, if you present lots of bad proofs for God's existence, that'll mean that you have lots of tiny chances for God existing. Get enough bad proofs and the chances will add up so something significant. Eventually they'll approach 1. Score!

I can almost hear my supervisors for probability and analysis vomiting in synchrony...

By  Lifewish, at 12:55 PM

• As I've said elsewhere, the first step is perfectly legitimate; a prior probability of .5 is conservative.

By  Robert O'Brien, at 1:46 AM

• Robert,

Okay, you said it...

But why should we believe it?

By  Daniel, at 6:43 AM

• Mark,

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].

By  Daniel, at 6:50 AM