HIV/AIDS Skepticism

Pointing to evidence that HIV is not the necessary and sufficient cause of AIDS

Posts Tagged ‘controversy about HIV/AIDS’


Posted by Darin Brown on 2008/05/23

Perhaps the most common reaction to dissident arguments is the argumentum ad populum, more commonly known as the “argument from consensus”. You know, “Fifty Million Frenchmen Can’t Be Wrong”. This is perfectly exemplified by a quote Robert Gallo gave to Anthony Liversidge in 1989:

“There is no organized body of science that thinks it is anything but comedy with Peter right now. That’s the fact. Why does the Institute of Medicine, WHO (World health Organization), CDC (Centers for Disease Control), National Academy of Sciences, NIH, Pasteur Institute and the whole body of science 100 percent agree that HIV is the cause of AIDS? If there was anything to what Peter is saying, wouldn’t it occur to you that there would be some other scientists that would agree with Peter? Can you tell me anyone?”

Twenty years later, little has changed:

“Debating denialists dignifies their position in a way that is unjustified by the facts about HIV/AIDS. The appropriate way for dissenting scientists to try to persuade other scientists of their views on any scientific subject is by publishing research in the peer-reviewed scientific literature. For many years now, AIDS denialists have been unsuccessful in persuading credible peer-reviewed journals to accept their views on HIV/AIDS, because of their scientific implausibility and factual inaccuracies. That failure does not entitle those who disagree with the scientific consensus on a life-and-death public health issue to then attempt to confuse the general public by creating the impression that scientific controversy exists when it does not.” — “Answering AIDS Denialists”,

The argument from consensus is a logical fallacy. The truth of a claim is not dependent on how many people hold the claim to be true. There are many counterexmaples from history, but a favorite is Galileo’s advocacy of Copernicanism. The response runs as follows: “Almost everyone thought Galileo was wrong, but he turned out to be right. Therefore, just because almost everyone thinks something is true, doesn’t make it so.”

The fallaciousness of the argument from consensus is a banal fact which is hardly in dispute. Therefore, people arguing from consensus are forced to either defend their claims with other valid arguments or to defend the argument from consensus with further logical fallacies. The clever try their hand at the former; the dim-witted almost invariably try their hand at the latter by using a logical fallacy I like to call the “Galileo Gambit Strawman”.

The idea behind the fallacy is to replace the above response to the argument from consensus with a strawman called the “Galileo Gambit”. The fallacy runs like this: “Yes, Galileo was right when almost everyone thought he was wrong. However, for every Galilieo, there are a thousand Bozo the Clowns who are wrong. Just because you compare yourself to Galileo, doesn’t mean you are right. You are far more likely to be wrong. Stop using the ‘Galileo Gambit’.”

The “Galileo Gambit” has become a favorite tactic of pseudo-skeptics, as it was recently popularized by one of our favorite surgeons-turned-blogger “Orac” (“Respectful Insolence”), certainly familiar to many readers of this blog. Unfortunately for dear Orac and his readers, it is a strawman argument.

When someone invokes Galileo as a counterexample against the argument from consensus, they are not asserting that because almost everyone disagrees with them, they are necessarily correct in their claims. Such an argument is patently absurd, and I have rarely, if ever, seen it advanced. When someone invokes Galileo, they are not claiming that such a comparison is sufficient to establish their claim, they are simply asserting that the example of Galileo provides evidence that consensus itself is insufficient reason to reject a claim.

The Galileo Gambit Strawman is committed in response to a perceived use of the Galileo Gambit, not the Galileo Gambit itself. It is ironic that such an elementary and obvious logical fallacy as this is perpetrated almost invariably by those who most claim to be “rational”, “skeptical”, and “scientific”.



For those wishing a more precise mathematical explication of the “Galileo Gambit Strawman” fallacy:


D = “Everyone disagrees with me.”, and

R = “I am right.”

The skeptic is saying

“~(D ==> ~R),”

where “~” indicates logical negation, in words,

“It is not the case that because everyone disagrees with me, I am necessarily wrong.”

The defender counters

“~(D ==> R)”

in words,

“It is not the case that because everyone disagrees with you, you are necessarily right.”

The statement

“(D ==> R)”

in words,

“Everyone disagrees with me, therefore I am right.”

is called the “Galileo Gambit”, and it is correctly described as a fallacy.

But the skeptic did not say “(D ==> R)”, they said “~(D ==> ~R)”. So I call the strawman counter above from the defender the “Galileo Gambit Strawman”.

The Galileo Gambit Strawman then takes the precise form:

“~(D ==> ~R) <==> (D ==> R)”

The first statement is the correct argument against the argument from consensus. The second statement is the fallacious Galileo Gambit. Taking the two statements to be logically equivalent is the fallacious Galileo Gambit Strawman.

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