From Don Boudreaux, who is fond of analogies. Is this a good analogy, and if not, why not?
A team of the world’s finest physicians and pathologists combine to create a measure of “Gross Bodily Health” (GBH). The higher is a person’s GBH, the healthier he or she is.
GBH is an aggregate measure made up of measures of heart health, digestive health, pulmonary health, blood-pressure health, and a few others.
The main determinant of GBH is called “aggregate healthiness” (AH). Aggregate healthiness changes for any number of reasons – for example, a change in the frequency of a person’s exercise or a change in a person’s diet. Higher AH, common sense tells us, causes higher GBH…
Jones goes to his physician and finds that his GBH is dangerously low. “What should I do?” Jones asks his doctor.
“Increase your AH – your aggregate healthiness” the doctor helpfully responds.
“Oh, it doesn’t matter. Jog, take blood-pressure medication if you think you have high blood-pressure, stop smoking if you smoke, exercise more. Anything to raise your AH. What’s important is that you get your AH up!”
“But can you tell me WHY my GBH is so low? Can you give me any details on just what I should do to improve my GBH?”
“No can do. But not to worry, for it doesn’t matter. The use of aggregates is methodologically justified in many cases. GBH and AH are aggregates, and we physicians have determined that GBH and AH are indeed very useful aggregates.
“We understand that the specific values of these aggregates for each patient at each moment in time are determined by literally billions of different things going on in that patient’s body and with that person’s diet, exercise, stress, etc. And there are other physicians – such as Drs. Alchoan, Demsitz, Hayuk, and Klang – who are great experts at looking at these more-detailed aspects of your body’s inner workings. You can consult them, if you like.
“But be aware that the Best Expert Opinion among practioners of what we call the ‘New Medicine’ is that the phenomena studied by physicians such as Drs. Alchoan, Demsitz, Hayuk, and Klang – while important – are phenomena each so sufficiently distinct from AH that we can, and should, treat deficient AH separately from any ailments that might be diagnosed by the likes of Drs. Hayuk and Klang.
“Trust me. Get your AH up and you’ll be fine. Don’t bother yourself with just why your GBH is low. Those details aren’t nearly as significant as is the fact that your GBH itself – for it’s kinda, sorta like a real phenomenon (it is measurable!) – is too low.”
“Please calm yourself! I’m a candidate to win a Nobel Prize in medicine. I know what I’m doing. Can you deny that a higher AH will result in a higher GBH? Of course not! Healthiness is the main determinant of GBH, so the trick to raising your GBH is really rather simple: increase your AH.”
“But suppose I take blood-pressure medication even though my blood-pressure is fine. Won’t that hurt me? And what if my GBH is low because of a lung disease. How will I help myself by improving my diet? Shouldn’t I know the details of what ails me? And isn’t it the case that the specific causes of my low GBH should be treated individually. Increasing my ‘aggregate healthiness’ seems like a hamfisted way to go about improving my health. I have SPECIFIC things wrong with me; what’s wrong with me isn’t helpfully described simply as inadequate ‘aggregage healthiness.’”
“Look. I’m the expert. I know what I’m talking about.”