Abigail Zuger, in “A Pound of Prevention Is Worth a Closer Look”, a review of H. Gilbert Welch, Lisa M. Schwartz and Steven Woloshin, Making People Sick in the Pursuit of Health, in the NYT Science Times of January 25:
The authors [all M.D.'s, as is Zuger] deplore our habit of showering prescription drugs on those unlikely to beunefit from them. They trace it directly to the fact that once the experts have drawn the line in the sand that separates “health” from “disease,” we all tend to forget that both entities are etched in shades of gray, not the black and white the terms imply.
Similarly, the line between “normal” and “abnormal” is not the closed border most people envision but a no man’s land of substantial width. And so in our wild enthusiasm for seeking out tiny abnormalities, we often find them — thanks especially to the wondrous eyes of the latest high-priced scanners. Not necessarily the abnormalities we were looking for, but abnormalities nonetheless.
It’s the practice of scientists to draw sharp lines, even in domains (like medicine, psychology, and society/culture) where there’s quite a lot of gradience. In the case of health vs. disease and normal vs. abnormal, things are made more complex by the inclination of scientists to take folk labels and treat them as technical terms, with the result that ordinary people carry over their attitudes towards and beliefs about the categories and concepts in question into the the scientific domain — equating (as Zuger points out later in her review) normal with desirable “when it often means just the opposite” (and, for that matter, equating abnormal with diseased).