For many centuries, bleeding patients was a standard treatment for many diseases. Cancer? Bleed the patient. Headache? Bleed the patient. Fever? Bleed the patient. Pneumonia? Bleed the patient. Bleeding was accepted medical wisdom.
Perhaps surprisingly to modern patients, bleeding worked, at least some of the time. I.e. the patient would get better. Of course, a lot of the time if the doctor does nothing, the patient still gets better. No one bothered to ask whether it was the bleeding that caused the patient to get better or not. Few people even knew how to phrase the question.
Of course, sometimes bleeding didn’t work, in which case, the doctor drew more blood. If the patient died, then the doctor must not have bled enough, or bled the patient soon enough. It couldn’t possibly be true that bleeding was not a cure after all, or that even more unbelievably it actually killed the patient. The entire medical community going back to Galen supported bleeding. They had centuries of experience that bleeding worked.
With hindsight we can see that bleeding was insane. Why didn’t anyone stand up and say that this was ridiculous? That it clearly didn’t work, and harmed patients? Well, in fact a few people did but they were widely derided as crackpots because the entire medical community couldn’t possibly be wrong. Did they really think that all these learned men had wasted their careers, and were wrong? Maybe a doctor here or there could be wrong, but surely not all of them?
Of course, in the 21st century we no longer believe in bleeding. Nonetheless those of us with more education than common sense do sometimes seem to be wedded to the practices of the past, even when it’s obvious to any unbiased observer who hasn’t had the accepted wisdom of decades of learned men drilled into them that the accepted wisdom is wrong. In fact, it’s not only wrong; it’s actively counterproductive and is causing the very problems it claims to solve. We keep repeating the same failed prescriptions. When our tasks succeed in spite of our bad practice, we accept those as proof the practice is valid. When our projects fail because of our bad practice, we present excuses: We didn’t follow the plan rigorously enough. We didn’t start it soon enough. We didn’t believe hard enough.
What am I really talking about here?