Modern? fallacies on salt and health
One of the joys of my commute is the opportunity to listen to stimulating recorded lectures as part of The Teaching Company's Great Courses series. I'm in the middle of part 2 of a course by Steven L. Goldman, Ph.D. on "Great Scientific Ideas That Changed the World."
Lecture 13 on "The birth of Modern Science" discusses the contribution of Francis Bacon, an Elizabethan Renaissance man who developed the modern experimental method. Bacon developed his new method to overcome what he considered the intellectual fallacies of his time which he called "idols" of which there were four: idols of the tribe, idols of the cave, idols of the marketplace and idols of the theater. An idol, in Bacon's terms, was a fascination or fixation without basis in fact and which interferes from acceptance of an accurate understanding of some phenomenon.
Consider how relevant these fallacies are to the current debate on salt and health.
Idols of the tribe are deceptive beliefs inherent in society; they are based on error because they interpret observed relationships through the eyes of (current) orthodox opinion.
Idols of the cave are errors rooted in personal experience and limited by that experience.
Idols of the marketplace are errors rooted in semantics; words conjure up conclusions so the use of improper descriptors induces misunderstanding.
Idols of the theater grow from sophistry, a body of opinion sustained and perpetuated by group acceptance and popularity, but based on false assumptions.
How do Bacon's "idols" relate to the ongoing controversy over salt?
Tribe -- the overwhelming popular majority accept fallacious reasoning that because salt and blood pressure are related and blood pressure and health outcomes are related, that lowering salt will improve health. The evidence shows the contrary.
Cave -- Blood pressure researchers can manipulate subjects' BP by varying salt intake; therefore, they reason that changing BP alone, by any means (and an easy "means" is changing salt intake) will produce better health. There is no evidence to support this conceit.
Marketplace -- It's too bad recently-deceased William Safire didn't address this point. Assertions of "excess dietary sodium" and conclusions that "we eat more salt than we need" are among the several sleights-of-hand employed by salt reduction activists. How do they know better than an individual's neural-hormonal system what is "too much" salt?
Theater -- There are several illustrations, but the easiest to see is the continued preoccupation with endorsement by "expert groups" of the policy recommendation to reduce dietary salt, all the while ignoring the lack of evidence of a health benefit.
We salute Francis Bacon for pioneering a modern scientific method. He would be right at home with his passionate advocacy in today's kerfuffel over dietary salt.
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