[smacktoward]

The problem is that it's not just "needless interventions" that can backfire. Even in situations where an intervention could unquestionably help, there's still plenty of ways for it to go wrong. The most obvious is human error -- a well-intentioned intervention that's disastrously mis-executed -- but that's just the beginning of the list, not the end.

What you have to remember is that for the vast majority of human history, medical interventions of all kinds were at least as likely to hurt the patient as they were to help them, because of our crude understanding of how the body works and how disease is communicated.

A textbook example is Oliver Wendell Holmes Sr.'s classic 1843 study of puerperal fever (http://en.wikipedia.org/wiki/Oliver_Wendell_Holmes,_Sr.#Medi...). It showed how doctors who were doing a completely routine intervention -- general examinations of the health of newborn babies -- were actually picking up that infection from babies who had it and then spreading it to others who did not, because they didn't sterilize their instruments and change their clothing between examinations.

This seems obvious to us today, but at the time it was quite shocking, because in thousands of years of medicine doctors had never sterilized their instruments or clothing when moving from one patient to another. It never occurred to them, because none of the prevailing theories of how diseases spread called for it. So untold numbers of newborns sickened and died because of well-meaning, completely uncontroversial interventions by their doctors.

Today doctors obviously do understand the role of germs in spreading disease better, and they have much improved medical technologies and practices available to them, which has helped reduce the risks of those types of interventions. But millennia of these types of unpleasant discoveries has given medicine as a profession a healthy regard for the possibility that what they think they know even today could be incomplete or flat-out wrong.

[tapp]

> Today doctors obviously do understand the role of germs in spreading disease better

And yet study after study of hospital acquired infections show that simple hand washing between patient examinations is abysmally irregular (between 10 and 50%.)