Reimagined and Revamped. Fighting the spread of nonsense often feels like a Sisyphean task. However, the joy is in making the information available, not the hope of conversion.

No True Scotsman Fallacy - science style.

I think I am going to do a couple of posts on perceptions of science. I am not in the science arena, I use it every day as an engineer and I understand many science related fields, from physics, chemistry, biology, electronics, mechanics, controls, etc. I'm more expert in some (electronics, controls, mechanics) and less expert in others (anything else).

By wife has almost no science related background, most of my friends have little or no science related backgrounds. Same goes for their parents, friends, new people I meet and so forth. In fact, most of this country has little or no science familiarity at all. No wonder we can't get on the ball with global warming and getting evolution to be the uncontroversial subject that it is. Same for all brands of woo that people keep paying for.

Anyway, on to the first subject. There is a common fallacy employed, often by religious people when you point out all the things wrong that so-and-so did as a Christian or Muslim. Or you may say to the fundamentalist," look, the Pope is cool with evolution". The response is something to the effect of "Well that person is not a real Christian". Moderates say this about fundamentalists, fundamentalists say this about moderates.

This is known as the "No True Scotsman" Fallacy. I wanted to point out that this is used not just by woo-mongers and the religious. Scientists, respectable ones, use this also. What makes it harder, is that sometimes they are not using it, but there is no reason to believe that they aren't unless you are already expert in the field. The NTS fallacy is perceived, but not actually used. Lets turn to Orac for the moment.

In a recent post, where he is decrying the actions of anti-vaccinationists (correctly I might add), he says this:

There is zero scientifically sound evidence that the MMR causes autism or other neurodevelopmental disorders--or even "autistic enterocolitis." None.
If I am an anti-vaccinationist, Orac just committed the NTS fallacy (replace the phrase 'scientifically sound' with the word 'real'). This is because, from my perspective, there is in fact, many, many studies that show this link. They are searchable on PubMed and have been in the Lancet. All I have to do is find the Wakefield studies, or anything by the Greiers. Look! There is published papers, there is evidence! If you are unfamiliar with the scientific process, if you are unfamiliar with what is good evidence and what is not, if you confuse the word hypothesis witht he word theory, you are going to think you have smacked Orac down with a reference to a few papers.

I have seen this exact same back-and-forth over at Skeptico's whenever anti-vaccine nonsense comes up (just search for vaccine, you'll find it). The hard part is that both Skeptico and Orac are correct. When the anti-vax studies are examined critical flaws in the procedure or interpretation of results are found.

Now don't get me wrong, this is part of the process of science, Wakefield made a claim and presented his evidence, his claim was examined, his results were attempted to be replicated, predictions were made based on his results and predictions were made by his detractors. The results of this process clearly shows that the wakefields and Greiers of the world, and their celebrity fan club are simply not right, no matter how much media they try to get.

My problem with all this is that its time to move on (as with so many other things). At the same time, how can we move on, if perceived NTS fallacies are employed by our most respected doctors, scientists and critical thinkers.?

I don't know the answer. I wanted to show that this is a problem.


On 7/30/08, 11:49 AM , Larry Hamelin said...

The No True Scotsman fallacy is a fallacy only insofar it changes an empirical claim to an analytic claim.

Alice: No Scotsman takes sugar in his porridge [an empirical claim: we must look at Scotsmen and their porridge to determine its truth]

Bob: Angus is a Scotsman, and he takes sugar in his porridge. [refutation of the empirical claim]

Alice: Ah but no true Scotsman takes sugar in his porridge [now Alice is making an analytic claim: A scotsman is defined to be a person who does not take sugar in his porridge.

It's especially fallacious and undproductive when the subject under discussion is imported into the discussion.

Alternatively, if Alice were to say, "Angus is not a true Scotsman; he might have been born in Aberdeen, but he was raised in Manchester."

Note that this is not a no true scotsman fallacy, at least insofar as sugar and porridge is concerned. It's still an analytic definition, it's about the definition of "scotsman", but it's not an attempt to "win" the empirical claim by turning it into an analytic claim.

Likewise the definition of "sound scientific evidence". If Orac were to say, "no sound scientific study by definition could shows vaccines to be unsafe", then he would be guilty of the NTS fallacy.

But he is making a claim about the definition of evidence that is analytically unrelated to the conclusion. Nothing about his definition directly entails one outcome or the other.

Sadly, most people are even more clueless about philosophy than they are about science, so the value of this analysis is probably minimal.

On 7/30/08, 11:49 AM , Larry Hamelin said...


It's especially fallacious and undproductive when the conclusion under discussion is imported into the definition.

On 7/30/08, 7:40 PM , Anonymous said...

It seems to me that Orac isn't making a No True Scotsman argument. A NTS is a post-hoc arbitrary moving of the goalposts to hide the fact that the original argument has been debunked. Orac is just saying that evidence must be scientifically sound - which isn't arbitrary or post hoc.

On 7/30/08, 7:58 PM , Techskeptic said...

Clearly I suck at this whole blogging thing.

The point I was trying to make was that I agree, Orac was not making an NTS fallacy. My point was that if you are not experienced in scientific reasoning or critical thinking, then it would appear that he was making one. These posts (this and the next one) will be about perceived fallacies as seen from people who do not have backgrounds that require these skills.

If you have followed that post I linked to at Orac's, there is a character there who displays an incredible skill at misunderstanding the science around vaccinations.

She is doing exactly what I am trying to write about. She has no ability to discern between a 'study' and a 'scientifically sound study'. So she posts links to ridiculous studies because she has not intuition at all as to what makes a good study, or even a good statistic, and upon reading Orac's post, she can't get past her perceived fallacies that Orac and others are doing.

On 8/4/08, 12:06 AM , Spoony Quine said...

I think I get it... hard-working scientists are just not completely sure what the hell's going on, so all are technically Scotsmen?

Is that it?

In any case, it's a lot more difficult to demonstrate than what I said about... well... But I did. Just ask the AMA!

On 8/12/08, 11:00 PM , Genewitch said...

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Email or whatever :-)

I have to read your site again, for some reason it fell off my rss feeder.

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