Thursday, August 26, 2010

Roger Pearse on how not to evaluate evidence

Among other things, on the abuse of the slogan "Extraordinary Claims Require Extraordinary Evidence."

11 comments:

Anonymous said...

Bob Prokop writing:

I like the way Roger thinks. The demand for “extraordinary evidence” has always seemed fishy to me, but I never could manage to clearly articulate why. Roger has done just that. It is really a cover for not taking a second (or even a first!) look at one’s own unexamined presuppositions.

The Obama as a Shape-shifting Alien is a good analogy. It would not take extraordinary evidence to convince me of such a thing – just plain ol’ ordinary evidence, such as somebody actually witnessing him mutate into an alien. In the same manner, I really have no need for extraordinary evidence for the Resurrection. I’ll settle for the garden variety evidence that we do have, such as 500 plus persons seeing Him, touching Him, speaking with Him, even eating with Him after He rose from the dead.

Hmm, let me weigh my alternatives here. Saints Matthew, Mark, Luke, John, Peter and Paul on the one hand – and John Loftus and Steven Carr on the other. I think I know where I’m placing my bets!

Walter said...

I believe we actually covered this in another thread. It is not that extraordinary claims require extraordinary evidence; it is that extraordinary claims require far more evidence than mundane claims do.

And many skeptics simply do not see the literary evidence of the New Testament as being sufficient to meet the greater burden of evidence required by miracle claims.

Anonymous said...

Bob Prokop writing:

Walter,
While meaning every word I wrote in my first posting, I am perfectly aware that I was having a bit of fun with its tone. But quite seriously, the wearingly repetitious demands for “extraordinary evidence” always seem to turn out in the end to be masks for deeper, quite illogical presuppositions that remain unexamined.

For instance, we often hear the objection, “Why didn’t Jesus rise from the dead in an era of television, or the hologram, or the digital age?” Completely sidestepping the issue of “just why do you thing you know better than God?”, this whole line of argument is thinly disguised chronological snobbery. The skeptic would endlessly object to Jesus walking the Earth in whatever century He chose, unless it were his own.

The Evangel has withstood attack for two millennia now – everything from armed assault to state suppression to cultural prejudice. (I am not one of those loonies who think Christians are somehow oppressed in the USA, by the way.) I don’t think the New Atheists are going to have any longer term impact on Western Christendom than did Stalin on the Orthodox Church. They’re getting their 15 minutes of fame right now, but people will still be exiting churches on Easter morning rejoicing that “Christ is Risen!” long after the name of John Loftus (or Bob Prokop, for that matter) is dust.

Doctor Logic said...

Walter is right, but we can be more specific about when extraordinary evidence is needed.

The primary lesson of our dear Reverend Bayes is that we ought to account for false positives. In particular, when the noise level of false positives is higher than the signal level, we need a lot more statistics (or statistical leverage) in order to increase our confidence in the theory.

For example, if Fred is in a car accident, Fred might attribute the accident to a conspiracy by aliens (or by the CIA) to knock him off.

However, while car accidents are improbable for individuals (say, once every 5 years), and the details of any specific car accident even more so (e.g., the particular makes and models involved), there is a noise level of car accidents. That is, car accidents would be happening even if aliens or the CIA were not causing them to occur. Thus, it takes extraordinary of evidence in order to convince us that Fred's accident was actually a murder attempt.

The NT is hearsay, and while there are peculiarities about the story, there aren't any more peculiarities about the NT story than there are about many other major events, e.g., the life of Adolf Hitler and the story of WWII.

Bottom line, people make up stories about the supernatural, people make up religions, and people delude themselves with respect to miracles. This happens every day. There is A LOT of noise out there. The Christian claim is that the NT is exceptional. But you need to do much better than a single source of hearsay to prove your story. And you'll never get it from hearsay because the evidence has long since been etched away by the sands of time.

And don't give me the story that "if Christianity were false, it would have been debunked in the first century." That's total bollocks.

Victor Reppert said...

That assumes that there is some measurable way of setting objective priors. Maybe there is, but any simplistic system for doing it that works. You have two people who don't believe in the resurrection. One of them is an atheist who has a Dawkinsian view of Christianity. Another nonbeliever is an agnostic who thinks there is a good chance there is a good, and if there were one, he would not expect God to sit on his hands in response to a sinful world. So, he would expect God, if he existed, to have spoken but where? In the Old and New Testaments? In the Qu'ran? In the Book of Mormon? In Dianetics? Where? Someone like that might find the Christian revelation at least halfway antecedently probable, even if he didn't believe yet. Extraordinary enough won't be the same for skeptic A as it is for skeptic B, nor should it be.

terri said...

I read Pearse's article.

A couple of things....rejecting an argument just because you don't like the people who frequently use it isn't an effective way to dismantle the argument. So...saying the librarians are unwittingly using "atheist polemic" doesn't really change the point that the librarians are making in the context of research, or the arguments validity.

When he talks about extraordinary events being associated with anything that isn't "normal" in our society, implying that the label extraordinary is arbitrary,.....it's a dodge.

The discussion isn't about what's normal in society. Society and its norms exist in the realm of human constructs and relationships.

"Extraordinary" events demanding evidence...like the Obama shape-shifter...are events making specific, material claims that aren't decided by a society's "norms" .

Whether a society would "normally" accept and promote a belief in shape-shifting aliens is a completely different track than whether or not there actually are shape-shifter aliens.

Mike Darus said...

Doctor Logic said:
"And don't give me the story that "if Christianity were false, it would have been debunked in the first century." That's total bollocks."

And: "And you'll never get it from hearsay because the evidence has long since been etched away by the sands of time."

It seems like the ONLY opportunity to debunk the evidence about the events first hand was IN the first century. That would have to be when the heavy lifting was done because, after that, you dismiss any testimony as only "hearsay."

Two thousand years later, in our humble courtroom, we don't get to cross examine eye witnesses. The author of Luke-Acts says he did. The evidence existed then and it was documented. I was even during a time where there was no political power to protect and no bureaucrats to defend. What more can you expect?

I am glad that Walter has stepped back from the requirement for "extraordinary evidence" because no one knows what that is. But the demand for "more evidence" is just as vague.

How much would be enough? How much evidence did Judas have? Why was that not enough for him? Maybe the cry for more evidence can never be satisfied. There comes a time when the Defence rests and the jury needs to decide based on the evidence it has.

Walter said...

How much would be enough? How much evidence did Judas have? Why was that not enough for him? Maybe the cry for more evidence can never be satisfied. There comes a time when the Defence rests and the jury needs to decide based on the evidence it has.

The jury is in as far as I am concerned ;-)

Doctor Logic said...

Victor,

Another nonbeliever is an agnostic who thinks there is a good chance there is a good, and if there were one, he would not expect God to sit on his hands in response to a sinful world. So, he would expect God, if he existed, to have spoken but where?

Really?!!

1) Your theory is that there is a good God, and you grant a high prior probability to this theory (probably because you have a desire for universal justice).

2) You expect that such a god would not sit on his hands in response to our sinful world (by the definition of goodness). (This bit sounds reasonable given (1) as a premise.)

3) You think this god would... come to Earth looking like an ordinary bloke, get executed, and then have his followers claim that he was resurrected?!! Seriously, that is what constitutes not sitting on one's hands?

I put it to you that the United Nations has done a million times less hand-sitting than God.

Even if you come up with a theodicy that takes care of that problem (which no one has), it doesn't change the fact that you set your priors in (1) based on desires, not based on experiences. The desire for X doesn't mean you ought to set your priors in favor of X. My desire for universal justice doesn't alter my prior that there exist agents or conditions that will ensure universal justice. Are you saying it should?

If I visit your house and I fancy a blancmange, should I set my prior for the theory that you have a blancmange in your fridge to some high value?

Doctor Logic said...

Mike,

It seems like your argument is "If the Resurrection is true, then the NT is the best sort of evidence we can expect to have survived."

This may be true. I'm not sure, but let's suppose that it is. It is irrelevant to my argument. My argument is saying we should consider the probability of getting the NT when no Resurrection occurred, and that this probability is higher still. Consequently, we need extraordinary evidence, and, as you point out, we're not going to get it. This doesn't help the Christian case at all.

I'll put this another way. Isn't it *possible* for some miracles to have actually occurred in the past, but for those miracles to not be believable in the present?

The longer period of time passes between the miracle and the present, the less plausible the miracle will be. Don't you agree?

It seems like your epistemology is like this: "It ought to be possible for us to believe an actual miracle, no matter how little evidence was left behind. Adjust epistemic rules accordingly."

BTW, hasn't the "vaccines cause autism" claim been debunked? How about astrology? 9/11 Conspiracy? Is this debunking stopping people from believing in these things? No. So why would the practice of debunking have been so much more common and effective in the first century? If it wasn't more effective, then why would you take the original purveyors of the Resurrection story at face value? The NT authors present themselves as ordinary, independent, skeptical men. That self-description doesn't mean they were ordinary, independent or skeptical. It means they were trying to persuade people.

Bilbo said...

Joshua Blanchard had an interesting take on Pearse's article here:

http://egalicontrarian.com/index.php/2010/08/27/extraordinary-evidence-and-extraordinary-claims-is-there-a-relationship/#comments