If you want a good example of how concerns about MMR vaccine being implicated with autism have left the realms of science and gone journeying into the wilder areas of quackery and pseudoscience, then the latest press release from Thoughtful House about the Hornig study is a good place to start. Brian Deer, a journalist with a keen interest in MMR vaccine, has produced helpful background on Thoughtful House, which you may wish to read.
Thoughtful House make three main points about this study.
- That the Hornig study clears earlier work by O’Leary laboratory that is a key aspect of a court case about MMR vaccine.
- That epidemiology has not cleared MMR vaccine of any association with autism.
- That the study rules out long-term presence of the MMR virus in the intestine, however Wakefield said “We need to consider that the MMR vaccine can cause autism as a hit-and-run injury, but not necessarily leave the measles virus behind.”
Using these arguments Thoughtful House claim that the Hornig study actually affirms the very studies that it actually refutes. Black is white, up is down.
Point 1 has been dealt with excellently by Kevin Leitch at LeftBrainRightBrain. Point 2 is hardly worth discussing, but I refer readers to a discussion about a Wakefield epidemiological commentary in a crank US journal, and an analysis of a graph attempting to make an epidemiological link between autism and MMR vaccine’s introduction in the UK and California produced by Wakefield in 1999. It is fair to say that the MMR vaccine-autism hypthesis is dead within serious epidemiological circles.
This post is about point 3. When does science become pseudoscience? This is the philosophical area that Karl Popper was concerned with in Science: Conjectures and Refutations. His key argument was a theory should be put at risk by observation and experimentation. While pseudoscience looked for confirmatory signals, and could be (and was) molded to fit any observable circumstances, science made predictions that could be refuted. He listed seven conclusions to his thoughts, which you can read here [PDF], but I’ll focus on one:
Some genuinely testable theories, when found to be false, are still upheld by their admirers–for example by introducing ad hoc some auxiliary assumption, or by re-interpreting the theory ad hoc in such a way that it escapes refutation. Such a procedure is always possible, but it rescues the theory from refutation only at the price of destroying, or at least lowering, its scientific status.
Wakefield’s attempt to produce an ad hoc “hit-and-run” re-interpretation of his measles virus in the bowel hypothesis, is a clear attempt to skip past the clear evidence that the Hornig study provides. He as much admits this, by not disputing the results.
That MMR vaccine is responsible for autism has become an article of faith for some. Terms of faith are even used on the UK’s leading anti-vaccine website to frame the debate, where one poster to their forums calls out to “disbelievers”. The language is not that of weighing the evidence, or examination of facts, but of conspiracy, of certitudes, and of the ulterior motives of those who do not accept the creed of Saint Andrew. “So no measles virus in the gut? But MMR vaccine must be responsible? Ah-ha! It must have done the damage and then been removed.”
This is a never ending dance. A game in which a belief is continually re-affirmed by use of a continually changing theory. As Popper also wrote:, “A theory which is not refutable by any conceivable event is nonscientific. Irrefutability is not a virtue of a theory (as people often think) but a vice.”. Those clinging to the MMR vaccine-autism hypothesis are in the realms of astrology, homeopathy, celestial teapots, and invisible dragons in your garage.
6 Comments
You have it spot on there, Anthony. We will never convince the true believers. but with so much real science out there it ought to be easier to steer the unpersuaded away from pseudoscience and quackery.
Thanks for this. I appreciate it that you are interested in what’s going on in the US with the antivax nonsense.
Yes – hopefully the fact that the Hornig article is open access will also make it easier for the unpersuaded to appraise the evidence.
When will people learn! It’s the Dihydrogen Monoxide content of vaccines that cause autism!
http://www.dhmo.org/facts.html
Article of faith, indeed. The reaction of Thoughtful House reminds me very much of a book I recently read about a religious group which believed the end of the world was coming. Every time something occurred to disprove the prophecy, such as the world failing to end on the first of what turned out to be several appointed dates, they simply made up some new corollary to their canon of belief. The further invested they became in this group – the longer they stuck with it despite the disapproval of others – the less inclined they became to ever give up their conviction that they were on the right track.
The other thing to really note about the Horning study is the authors. Including Hornig, Buie, Bellini, O’Leary and Sheils. Obviously the other authors are critical, but these people I’ve named are either former Wakefield collborators, or they are people who know Wakefield very well indeed, or they are people who he has cited as endorsing his claims. In other words, those right at the heart of this thing – and who are honest people – repudiate his claims.