"Junk science" still a popular subject.

John Tierney has an insightful piece about pesticides, and associated junk science, in his latest Findings column (New York Times). (I recommend his TierneyLab site, which he's using "to check out new research and rethink conventional wisdom about science and society.")

Today he lamented the fact that Rachel Carson's diatribe against DDT is seeing a resurgence, saying: "If students are going to read Silent Spring in science classes, I wish it were paired with another work from that same year, 1962, titled Chemicals and Pests. It was a review of Silent Spring in the journal Science written by I. L. Baldwin, a professor of agricultural bacteriology at the University of Wisconsin." Baldwin discovered some rather enormous flaws in the evidence Carson put forth: "She cited scary figures showing a recent rise in deaths from cancer, but she didn’t consider one of the chief causes: Fewer people were dying at young ages from other diseases (including the malaria that persisted in the American South until DDT). When that longevity factor as well as  the impact of smoking are removed, the cancer death rate was falling in the decade before Silent Spring, and it kept falling in the rest of the century."

As often happens, the abandonment of DDT did more harm in poor nations than it did here in the U.S. "The human costs have been horrific in the poor countries where malaria returned after DDT spraying was abandoned." (Yet another example of early, U.S.-centric environmental policy.)

Tierney mentioned another site I recommend: Junk Science (covering "all the junk that's fit to debunk"). I recall hearing its publisher, Stephen Milloy, speak more than 10 years ago on food science issues. Junk Science offers a DDT synopsis, with tidbits such as "Gas chromatography was universally used for pesticide analysis in the mid-1960's. But it often failed to differentiate between DDT residues and other chemicals."

Comments

[John Frum]

Undoubtedly that is an important point that is always worth teaching. However, we must be equally as aware of those who employ the increasingly common techniques of "teaching the controversy" or manufacturing doubt and undermining one piece of evidence offered in support of a much more complex argument/policy.

The classic example is smoking and lung cancer: undermine the statistical certainty and/or lack of causality [by definition inherent] in one epidemiological study and voila - smoking doesn't cause cancer.

This is an extreme example, but my point is this: examining evidence critically within the proper context is unremarkably proper, and if this was the only line of evidence offered to support a broader argument, then we would be justified in drawing conclusions about its validity based solely on the weakness in this evidence; however, this artifically narrow context is rarely - if ever - applicable.

Thus, to over-generalize as you and Mr. Tierney did [and basically skip over the rest of a complex multifactored analysis] and make assertions about the validity of a broader policy iniative based solely on the weakness of one line of evidence offered by one person in support of said intitiative is simple logically fallacious reasoning.

This is unfortunately a very common human fallacy often employed by those seeking to manipulate public opinion on a variety of topics. As much as weak evidentiary analysis should be called out and addressed anywhere it rears its head, such rhetorical and logical obfuscation - wittingly or unwittingly repeated - should not go unchecked.

This lesson is as important as the first, as this argumentative technique is often employed by those trying to label anything they do not agree with as "junk science" (or more commonly not "sound science"). I do not doubt your sincerity or motives (I detest what most would agree as "junk science" myself), but I am seeing more and more of this type of illogical reasoning in the public discourse and it is more than disconcerting.

[Tracy Allison Altman]

My reason for this post was to make the point that students should be getting more sides of a story: If they're reading Silent Spring, then teachers should also be assigning a counterpoint to it. That way students will learn to weigh conflicting evidence, will begin to appreciate the complexity of many environmental issues, and learn the importance of watching for unintended side effects.

[John Frum]

Let me first say that I have nothing to say about the flaw's in Ms. Carson's evidence/logic/science.

As you well know, risk (to humans, birds, etc.) is analytically distinct from the benefits in any such evidence-based analysis.

And furthermore, it is logically fallacious to argue that a conclusion/policy is false simply because an argument given in support of it is invalid [or its premiss false].

With this being said, I would merely ask you to explain this broad conclusion (remember: merely pointing out the flaws in Carson's "science" is of no significance):

"As often happens, the abandonment of DDT did more harm in poor nations than it did here in the U.S. 'The human costs have been horrific in the poor countries where malaria returned after DDT spraying was abandoned.'"

Where is the rest of the analysis?

For example: What were the benefits of DDT (and thus the "human costs" of its abandonment)? Since there is ample evidence that factors such as DDT resistance served to prevent eradication more than Carson & the hippies, particularly in the tropics, its strikes me as a very important question, heh?

While I agree that Carson "science" was in many respects flawed, drawing such a conclusion based only on such flaws is just weak logic that seems to muddy what is a very complex multi-factored policy debate.

It would be more than a bit ironic to blindly accept assertions made by one journalist (Tierney) to attack the scientific reasoning of another.