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Bold Conjecture, or Established Fact?

In the post on Climate Change and the Nature of Scientific Certainty, I offered this true-or-false quiz:

  1. Marijuana has a higher potential for abuse, relative to cocaine and morphine
  2. Mercury in dental amalgam has no negative health consequences
  3. Reducing your consumption of saturated fat will improve your health outcomes
  4. GMO foods are safe
  5. Better to eat margarine instead of butter
  6. The bodily effects of high fructose corn syrup are the same as any other form of fructose
  7. Reducing your cholesterol will reduce your risk of coronary heart disease.
  8. Making contraceptives more widely available to teenagers leads to an increase in their sexual activity.
  9. Raising the minimum wage leads to loss of jobs.
  10. Carbon in the atmosphere follows a drug dosage model: when it increases, the planet gets warmer, and when it is made to decrease, the planet cools back down.

Here is my take on where matters stand.

Knowledge claim My call

Discussion
1.     Marijuana has a higher potential for abuse, relative to cocaine and morphine

 

  

F

 The scientific consensus on this statement has been embodied in Federal law for decades, with marijuana classified as a Section I substance, and morphine and cocaine as Section II. The absurdity of this claim was a prime factor in fueling skepticism toward the Establishment among baby boomers of my generation.
2.     Mercury in dental amalgam has no negative health consequences

 

 T In scientific terms, “mercury in fillings poses a danger” holds the same epistemological status as “vaccination causes autism.”  I include it here to tweak younger and more leftist climate change insisters, many of whom probably have their doubts about mercury.
3.     Reducing your consumption of saturated fat will improve your health outcomes

 

 ? Until recently, this health claim (“saturated fats are bad for you”) was on a par with “vaccination is good for us.” Now the initial evidence (a large correlational study where weak findings were hyped) been called into question, and there is no longer any consensus.  I include this case as an example of how scientific consensus, at least in fields like medicine, can change on a dime.
4.     GMO foods are safe T This one is included to tweak the more politically correct and the conventionally left wing.  The science behind the safety of GMO foods is at least as strong as climate science. People who split their position—climate change yes, GMO foods no—are more politically motivated than they wish to acknowledge.
5.     Better to eat margarine instead of butter F This used to be the orthodox medical position: millions were told to make the switch.  Then, research on trans-fats began to appear…
6.     The bodily effects of high fructose corn syrup are the same as any other form of fructose

 

 T If “bodily effect” is defined narrowly enough—the metabolic cycle in cells, say—then the evidence for this statement is on a par with that showing mercury in fillings to be safe.  If “bodily effect” is defined more globally or holistically, in terms of how people dine, and the interaction between diet components and dining habits (e.g., over-eating), then the statement becomes a question mark
7.     Reducing your cholesterol will reduce your risk of coronary heart disease. ? Like saturated fat, this case shows how scientific consensus can solidify for a time, and then fray or even crumble. Just as climate change recommendations extrapolate from the observed correlation between temperature and carbon to a specific dosage model, cholesterol recommendations likewise translated an observed correlation in the field to a specific dosage model. It’s no longer clear that artificially depressing cholesterol levels using a drug intervention translates directly into improved mortality
8.     Making contraceptives more widely available to teenagers leads to an increase in their sexual activity.

 

 F Not every intuitive hypothesis can be supported scientifically: http://pediatrics.aappublications.org/content/120/5/1135
9.     Raising the minimum wage leads to loss of jobs.

 

 ? Studies exist to support all viewpoints on this issue. But, conviction on both sides runs as hot as with climate change. Useful as a reminder that dubitability of scientific knowledge is not limited to medicine.
10.  Carbon in the atmosphere follows a drug dosage model: when it increases, the planet gets warmer, and when it is made to decrease, the planet cools back down.

 

 ? Note the independence of this knowledge claim from claims about global warming.  One can accept global warming as a fact, while being cautious about extrapolating from observed correlations to specific dosage models–as in the case of cholesterol.