Be a skeptic when an advocate starts talking about “deniers”

Not climate in this example but obesity. Steven Novella gets going on “deniers” in a post wondering Does Weight Matter?.

“The data, however, are likely to be complex and noisy, and therefore there is plenty of opportunity for ideology to trump objectivity in interpreting the data. There are those who, for whatever reason, deny that we are having an obesity epidemic in the West, and those who deny the health implications of being overweight as an independent factor.”

The data is “complex and noisy” but if you don’t believe as he does, you “deny” ?? An example of a convenient, but not direct, measure is BMI. It has been used to categorize classes of obesity for research and the criteria for those classes have changed yet there is this:

“This event in 1998 now has become a central argument in the arsenal of obesity deniers. … those who wish to deny the “obesity epidemic” have found BMI to be a convenient target for sowing doubt.”

A large part of the post is about this categorization and classification and health impact only shows up at the end. There, too, is the impugning of any disagreement.

“The data is clear – but complex, and so allows for those motivated to deny the connection to distort and cherry pick the data to create the impression they wish.”

That is coupled with what may be a bit of projection:

“Here we see a couple of logical fallacies. The first is the denial of cause based upon an overapplication of the “correlation does not equal causation” fallacy. It is true that correlation alone does not prove causation, but causation may be the answer, and we can test this hypothesis by testing multiple correlations. For example, if weight is reduced will the risk of the disease decrease.”

Consider the logical problems of creating causation out of correlation by finding yet more correlation. This particular difficulty is rationalized with an analogy.

“We also see confusion between weight as a risk factor vs being an absolute cause. Weight is one factor among many, such as genetics. There are obese people who are otherwise healthy, just like there are heavy smokers who never get lung cancer.”

The fact that there are “obese people who are otherwise healthy” falsifies the assertion about causation. This is acknowledged by noting that the issue is complex and that there are very many factors other than obesity. This acknowledgment, however, is not allowed to interfere with the conclusion.

“It is also folly to tie a social/ethical issue to a specific factual premise – because when the facts don’t come out the way you wish that either weakens your ethical stance, and/or forces you to deny the scientific facts. We can simultaneously treat overweight and obesity as the health problem that it is, while addressing the social and psychological aspects of weight in our society.”

In the analogy provided, there is a well supported model that has survived testing that describes the mechanism for the link between smoking and cancer. Both the cause and the effect are fairly narrow in scope and well defined. When it comes to Novella’s assertions about obesity, neither the condition nor its effects are clearly defined and no model for the mechanism, as a generality, is well established and tested.

That lack of standards and the ambiguities and the establishment of an army of straw men often correlates with the use of ‘denier’ to label those in disagreement with an ideologue. A first step towards gaining credence on issues like this is an expression of intellectual integrity and these characteristics do not express that.

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