Thursday, April 26, 2012

ad hominem, no true Scotsman, and arguments from authority

I just thought I'd write a quick note on the ad hominem and no true Scotsman fallacies, because I've noticed a lot of people being confused by them.

A lot of people confuse an insult for an ad hominem fallacy.  Ad hominems do often involve insults, but they don't necessarily, and not all insults are ad hominems.  If I said that you're a man, and therefore your opinion on abortion cannot be trusted, I'm using an ad hominem argument, but I'm not insulting you.  Calling you a man is not a criticism.  It's just an observation about you that is irrelevant to the soundness of whatever argument you have for or against abortion.  If you gave me an argument against abortion, and my reaction was to call you an idiot, that is not an ad hominem.  That's just an insult.  It only becomes an ad hominem if I say something like, "Since you are an idiot, you must be wrong about abortion."  An ad hominem is when you point to something about a person that is irrelevant to the soundness of their argument or the truth of their point of view, but you offer it as evidence against their point of view or the soundness of their argument.

A lot of people lately have been accusing Bart Ehrman of the No True Scotsman fallacy, but they are confused about what the fallacy is.  A fellow named Jason Goertzen had this to say in the comment section of Ehrman's piece called "Acharya S, Richard Carrier, and a Cocky Peter (Or: "A Cock and Bull Story")":

I lost count of the number of times you felt the need to point out that "no serious scholars" (a variant of the No True Scotsman fallacy, given how strenuously you define what you mean) believes x, or y; to the person who wants to be convinced, this isn't adequate.

Ehrman doesn't dismiss people as being serious scholars because they deny the existence of Jesus.  A fellow named Steve Bollinger said on his blog:

But it's not merely that Ehrman declares the discussion to be over; he states as well, on no firm basis whatsoever if you ask me, that no accredited professor in the Western World "who teaches New Testament or Early Christianity or even Classics" disagrees with him.  That already puts Ehrman into no-true-Scotsman territory.

Ehrman doesn't dismiss these people because they deny the existence of Jesus, so this is not the No True Scotsman fallacy.

Here is an illustration of the fallacy:

Jim:  No Scotsman would ever tell a lie.

Bob:  But Dan is a Scotsman, and he tells lies.

Jim:  Dan is not a true Scotsman.

Bob:  Why do you say that?

Jim:  Because no true Scotsman would ever tell a lie.  The fact that he tells lies proves that he's not a true Scotsman.

The No True Scotsman fallacy trades on a distinction between an analytic truth and a synthetic truth.  If being honest were part of what it meant to be a Scotsman, then when Jim says no Scotsman would ever tell a lie, he's not making a synthetic statement.  He's making an analytic statement.  He's giving us part of the definition of a Scotsman.  If he's right, then Bob is stating a contradiction.  Saying that Dan is a Scotsman who tells lies is equivalent to saying, "A person who tells no lies, actually does tells lies."

The No True Scotsman fallacy only comes into play when statements like "No Scotsman would ever tell a lie" is a synthetic statement.  Jim isn't saying that it's part of the definition of a Scotsman that they don't tell lies.  He's saying something that happens to be true about Scotsmen, but it's not a necessary truth.  It's not part of the definition.  In fact, it's possible that a Scotsman could tell a lie even if none ever have.  In that case, Jim is committing a fallacy when he objects to Dan being a Scotsman merely on the basis that Dan tells lies and no true Scotsman tells a lie.  If you reason that way, then you're basically just dismissing the possibility of counter-examples to your claim.  Jim is treating a synthetic statement as if it were an analytic statement.

In the case of Bart Ehrman, he has claimed that most of the mythicists who deny the existence of  Jesus are not credentialed scholars.  For that, he is being accused of committing the No True Scotsman Fallacy. But to be guilty of the No True Scotsman fallacy, Ehrman would have to be saying that the reason these mythicists are not credentialed scholars is because they deny the existence of Jesus.   It would have to go something like this:

Bart:  No credentialed scholar of the New Testament would ever deny the existence of Jesus.

Robert:  But D.M. Murdock is a credentialed scholar, and she denies the existence of Jesus.

Bart:  The fact that she denies the existence of Jesus is precisely why I say she is not a credentialed scholar.

But that is not how Ehrman has been arguing.  Rather, he's been saying that she and most mythicists are not credentialed scholars because they do not have advanced degrees in the relevant areas, they are not published in peer reviewed academic journals, and they don't hold teaching positions at any colleges or universities on the relevant subjects.   A person might still accuse Ehrman of the No True Scotsman fallacy on the basis that every time somebody comes up with a counter-example, Ehrman changes his definition of what counts as a "credentialed scholar" so as to dismiss the counter-example.  But so far, to my knowledge, this has never happened.  These are not arbitrary criteria for what counts as an expert meant to exclude people who deny the existence of Jesus.  I remember when I had to write papers in college, pretty much all of my professors, whether in philosophy or history, demanded that our secondary sources be academic.  I remember one of my philosophy professors specifically said that we could not quote from a web page called "Joe's Automotive and Existential Philosophy."  Credibility in our sources mattered, and we had to use scholarly sources.

But let's suppose it turns out that Ehrman argues something like this:  Since most mythicists are not credentialed scholars, their opinion on the existence of Jesus is false, or their arguments against the existence of Jesus are unsound.  If he argues that way, then he's not committing the No True Scotsman fallacy.  Rather, he's committing an ad hominem fallacy.  A person's credentials are irrelevant to whether their point of view is true or their argument is sound.

A person's credentials are not completely irrelevant in this whole debate, though.  They are relevant only in cases of arguments from authority.  If you cite Richard Dawkins as an authority on the cosmological argument, then that is a fallacious appeal to authority because he has no expertise in the subject.  But if you quote Richard Dawkins as an authority on the subject of gene replication, then that is not a fallacious appeal to authority.  He actually is an expert in the subject of biology.  An appeal to authority is only a fallacy if the authority you appeal to is not an expert on the subject you cite him on.  If somebody is actually an expert in the subject of the New Testament or historical Jesus studies, then their opinion is relevant.

But some people will claim that any appeal to authority is a fallacy since it's the argument the authorities use that count, and not the mere fact that they are authorities.  I vaguely remember Robert Price going so far as to say there are no authorities when it comes to the historical Jesus.  I think he may have a point.  The opinions about Jesus in academia are diverse.  If the experts disagree, then it's fallacious to quote one of the experts to support a view that's actually controversial among that expert's peers.  On the other hand, there are a handful of things about Jesus for which there is a strong consensus among experts, e.g., he was baptized by John the Baptist, he had disciples, he preached about the kingdom of God, he used parables in his teaching, he was known for being a miracle worker, and he was crucified on the orders of Pontius Pilate.

In his recent podcast, Price said he had written a pieces called "Paradigm Policemen," where he criticized Bart Ehrman for vociferously defending the status quo.  Price made what I thought were some good points, but I think he went too far.  It is true that the mere existence of a consensus does not mean the consensus is right, and it's true that if we stick to consensus and never dare to challenge it, that we stifle progress.  After all, we can point to moments in our history when paradigms were overturned, often with much difficulty.  The Copernican Revolution is one of the most famous examples.  Price thinks it's a mistake for Ehrman to criticize mythicists merely on the basis that they are going against the current consensus on the existence of Jesus.  I think he's right, but on the other hand, I do think consensus counts for something.

Most of us are not experts in any field.  We're armchair theologians, armchair philosophers, armchair historians, armchair biologists, etc.  Most of our education comes from reading books, not doing our own research.  Many of us read books and think that counts as doing research.  But really, for the majority of our educations, both formal and informal, we rely on the findings of experts.  If consensus counted for nothing, then our educations would be worthless.  We could read a dozen books on the historical Jesus or evolution and still not know anything.

Sometimes, if you're writing on a historical point of view, it is too tedious to spell out the arguments for every little piece of evidence you bring forth.  Even scholars, when writing on the historical Jesus, will appeal to studies that other scholars have done on some small point, then use that small point as part of their case for their point of view.  It helps when there's a consensus because then you can use that piece of information in your case without too many people raising objections about it.  If consensus didn't matter, or if expert opinion didn't matter, then we would never be able to build on information discovered by other people.  Everybody who wrote on any subject in history or biology would have to start from scratch.

I think we should lean in favour of the experts, especially when there's a consensus, but we should not do so dogmatically.  We should be willing to go against consensus when we ourselves have done enough research or have been adequately persuaded to hold a differing opinion.  I can't tell you what's adequate. You have to judge that on a case by case basis, and in a lot of cases, it's subjective.  But I don't think we should fault mythicists merely on the basis that they are in the minority.

However, I think it is appropriate to point out that there is a strong consensus among experts on the existence of Jesus to people we run into on the internet because most of them haven't done any research.  They've watched Zeitgeist and just took their word for it.  If they're going to just take somebody's word for something, then they should take the word of those who are actually credentialed scholars.  It's appropriate to bring up the consensus for a lot of those people because they may just not know any better. Two or three years ago, I got an email from somebody who had just seen Religulous with Bill Maher.  Apparently, Maher had brought up the whole myth thing, which was completely new to the person who emailed me.  She did a quick google search, found a short article on Religious Tolerance about Jesus and Horus, and was convinced.  This was all new to her, and she wanted to see what I'd think.  I think she half expected me to be surprised.  I think it was perfectly appropriate for me to point out that almost every single New Testament scholar or historical Jesus scholar believed that Jesus really existed, and that it wasn't even a serious debate in academia.

I'm rambling, aren't I?  Okay, I'l stop.

Bart Ehrman and Richard Carrier

With those two names in the subject line, I'm bound to get a huge boost in readers in a short amount of time.  I don't have much to say that hasn't already been said, though, so I'm just going to post links to the back and forth.  This is mostly for my own benefit so I don't have to go hunting around later if I want to read it all again.

Did Jesus Exist? by Bart Ehrman

"Ehrman on Jesus: A Failure of Facts and Logic" by Richard Carrier (I'm going to include a link to page 16 so I don't have to click through 16 pages to get to the comment section.  Yeah, I know there's a link directly to the comment section on each page, but the link isn't working for me.)

"Acharya S, Richard Carrier, and a Cocky Peter (Or: 'A Cock and Bull Story')" by Bart Ehrman

"Fuller Reply to Richard Carrier" by Bart Ehrman

"Ehrman's Dubious Replies (Round One)" by Richard Carrier

There are also some other blogs responding to each of them.

In response to Bart Ehrman

"The historicity of Jesus: Bart Ehrman responds to Richard Carrier (sort of)" by Jerry Coyne

"The Bible Geek" by Robert M. Price.  <--this is a podcast.

In response to Richard Carrier

"A Look at Richard Carrier's Critique of Bart Ehrman: Part One" by Eric Chabot

"A Look at Richard Carrier's Critique of Bart Ehrman: Part Two" by Eric Chabot

"The Death of Richard Carrier's Dying Messiah" by Thom Stark

"The Torturous Death of Richard Carrier's Dying Messiah" by Thom Stark

Mythtic Pizza and Cold-cocked Scholars" by R. Joseph Hoffman.  This one isn't really much of a response to Richard Carrier.  I included it because it's entertaining reading, but it's really just a snarky commentary on mythicists reactions to the Carrier/Ehrman drama.

There are others that I didn't include because I didn't think they contributed as much to the conversation or they lacked entertainment value.  If there are others you'd like to include, put them in the comment section.

Tuesday, April 24, 2012

Affirming the consequent and predictive value

In the hard sciences, the ability of a theory to make accurate predictions is taken to count in favour of that theory.  Let's use gravity as an example.  Although on earth, nobody had ever dropped a feather at the same time they dropped a heavy dense object and observed them falling at the same rate, the theory of gravity predicted that they should fall at the same rate if you eliminate all the forces (especially air friction) and drop them in a vacuum.  Since then, the theory has been tested by dropping feathers and bowling balls together in vacuums and found to be true.  The feather and the bowling ball do drop at the same rate in a vacuum where there is no air resistance.  That counts in favour of the theory of gravity.

Criminal investigators use this kind of reasoning, too.  For example, when somebody flees, that's taken as evidence of their guilt because fleeing is exactly what we'd expect from somebody who's guilty.

Historians also use this kind of reasoning.  I can't think of an example off the top of my head, but if I did, the scenario would be pretty much just like the criminal investigator scenario above.

This type of reasoning appears to commit one of the most basic formal fallacies called "affirming the consequent."  It takes this form:

1.  If P, then Q.
2.  Q
3.  Therefore, P.

In the case of gravity, the reasoning would look like this:

1.  If the theory of gravity is true, then a feather and a bowling ball should drop at the same rate in a vacuum.
2.  A feather and a bowling ball DO drop at the same rate in a vacuum.
3.  Therefore, the theory of gravity is true.

This whole principle of predictive value seems to depend on this fallacy:

1.  If theory X is true, then effect Y should be observed.
2.  Effect Y is observed.
3.  Therefore, theory X is true.

Don't get me wrong, though.  I'm not trying to argue that the predictive value of a theory does not count in its favour.  What I suspect, instead, is that it's not a deductive argument, and it's a mistake to characterize it as such.

Monday, April 23, 2012

Historical Jesus and evolution; mythicism and intelligent design

I just finished reading Did Jesus Exist by Bart Ehrman yesterday. There is an interesting parallel between the intelligent design vs. evolution debate and the mythicist vs. historicist debate.

99% or more of the experts in the field of biology and evolution subscribe to the theory of evolution, and although intelligent design advocates would like to be taken seriously, the overwhelming consensus among credentialed scientists in the field prevents it. People often point out the strong consensus in an effort to discredit intelligent design as "going against science." Intelligent design advocates think we should "teach the controversy" because intelligent design should be judged on its merits, not a false appeal to authority or consensus.

More than 99% of the experts in the field if New Testament history think Jesus existed, and although mythicists would like to be taken seriously, they can only gain a foothold on the internet among laymen. Christian apologists point out the strong consensus among experts in an effort to discredit mythicists, but mythicists insist that you can't arrive at truth by counting noses, and their arguments should be taken seriously.

There are a couple of differences, though. First, there are more peer reviewed academic articles published by mythicists (almost exclusively by Robert Price) than there are by intelligent design advocates. Second, while there is only one credentialed scholar in New Testament studies (Robert Price) who currently subscribes to the mythicist position, there are several credentialed biologists who currently subscribe to intelligent design. There are some people who are experts in related fields, though. Richard Carrier is an expert in ancient history, and Steven Meyer is a philosopher of science.

The reason I'm writing this is to try to get people to be consistent. If you think a strong consensus matters in the case of Jesus' existence, then don't casually dismiss the significance of the consensus when it comes to biology. If you think your case should be judged on its merits when it comes to intelligent design, then then judge the mythicist position on its merits, too.

If you think intelligent design should not be taught in school just because it hasn't gotten a foothold in the scientific community and that the predominant scientific view should be taught on a given topic and that time shouldn't be wasted on obscure theories that hardly anybody believes, then you should be consistent and say the mythicist position should not be taught either since it hasn't gotten a foothold in New Testament historical studies, and the predominant historical view is that Jesus existed, and teachers shouldn't waste time addressing obscure theories that hardly anybody believes.