The most insidious errors arise from explanations convincing enough to bring the search for alternatives to a halt.
In the popular imagination, a good doctor is one who reaches a diagnosis straight away. They listen to the patient, observe a few decisive details and say the right word. This owes much to an old, reassuring image, deeply rooted in Western culture. We doctors, too, fall under its spell. After years of study and practice, identifying a condition offers a form of intellectual gratification. It means having recognised a pattern within the apparent disorder of symptoms and being able to give a name to something that, until a few moments before, had none.
Yet, through my work in clinics and operating theatres, I have become convinced that diagnosis occupies too important a place in contemporary medicine, almost an overrated one. We tend, in fact, to regard it as a destination when, at best, it should be seen as an intermediate stage on the way to the patient’s wellbeing.
Reading Popper helps us understand how to navigate this difficult path. The philosopher maintained that knowledge advances not through confirmation, but through refutation. In other words, a scientific theory becomes more reliable not because someone considers it true, but, on the contrary, because it has withstood attempts to demonstrate its limitations.
When I read this, it seemed to me an observation valid only for physics and the philosophy of science, but today I think it applies just as precisely to a doctor’s everyday work.
Medicine, then, according to Popper, can be seen not as the science of answers, but as the discipline that seeks to minimise the number of wrong questions.
Some time ago I examined Edmondo, a patient who had already undergone surgery for carpal tunnel syndrome. The operation had been performed correctly, yet some symptoms persisted, with discomfort and pain at night. Nothing particularly unusual: every hand surgeon encounters patients who recover more slowly than expected or who continue to report residual symptoms, perhaps because they underwent surgery at an advanced stage of nerve compression. On an initial reading, the diagnosis accounting for Edmondo’s symptoms would have been a sensitive, painful scar, associated with prolonged nerve damage and incomplete recovery. All too plausible.
With experience, one learns that the most insidious errors in medicine almost never arise from outlandish ideas: those are dismissed at once. Rather, they arise from reasonable ideas, from explanations convincing enough to bring the search for alternatives to a halt.
As I examined Edmondo, certain details slowly began to emerge. The index finger and thumb were slightly larger in proportion than the other fingers and those of the other hand, but not enough to attract immediate attention. An ultrasound scan of the median nerve then revealed an unexpected finding: the nerve was enormously enlarged, and its fascicles appeared to be separated by abundant fibrofatty tissue, producing a characteristic image that English-language authors describe with a simple, effective phrase: spaghetti-like appearance.
In the light of the new findings, the final diagnosis was lipomatosis of the median nerve associated with a mild form of digital gigantism. This is a rare condition, but that is not the interesting aspect of the story, because rare diseases do occur, albeit less frequently than others. What I find significant is that most of the clues needed to suspect it had been there all along, since Edmondo’s hand had not suddenly changed shape. What had changed, if anything, was the way we looked at it.
The initial operation had been performed correctly, but it was the right operation for an incomplete diagnosis. And, indeed, the resolution of the symptoms had also been incomplete.
We are accustomed to imagining error as the product of ignorance, assuming that a doctor makes mistakes because they do not know enough. In reality, the opposite often happens: the greater our expertise, the greater the risk of recognising too quickly what we believe we have seen before. Experience makes us efficient at recognising patterns and, for that very reason, sometimes less sensitive to the anomalies that contradict them.
Atul Gawande, a surgeon and writer, has spent much of his career studying a subject many colleagues dislike: the errors made by healthcare professionals. He has devoted many pages to this subject, and his insight concerns not a branch of surgery, but human nature. Even the best professionals forget details, overlook information and construct premature explanations; this is why safety comes not only from individual expertise but from systems that oblige that expertise to confront doubt continually.
Checklists, multidisciplinary discussions, second opinions and exchanges between colleagues are tools designed to counter a deeply human tendency: that of growing attached to our own convictions.
On closer inspection, Popper and Gawande are talking about the same problem from different perspectives. The former asked how knowledge progresses, while the latter asked how errors can be reduced. Both reach a similar conclusion: the best ideas are not those we find most convincing, but those that survive the greatest number of objections. In my daily work, I have learnt to trust those willing to question their convictions more than those who defend them at all costs.
I find reassurance in a colleague who consults others, who seeks a second pair of eyes when a case leaves them less than fully convinced, rather than in someone who believes they always have an answer ready. And I continue to regard as a virtue the professional curiosity that prompts us to return to MRI images, reread a test result and check an apparently minor detail. In other words, in medicine, safety is far more necessary than certainty.
Edmondo’s story does not show that doctors make mistakes. We have always known that. It shows that the quality of a clinical decision often depends on a willingness to question an apparently satisfactory explanation.