There is a confusion here. The diagnostic process and the gathering of knowledge are two substantially different matters.

Diagnosis is consideration of an individual. Knowledge is consideration of the universal.

Diagnosis is a process of making hypotheses about an individual's symptoms and testing these until arriving at an explanation that fits the symptoms into current knowledge.

This knowledge may be less substantial than we wish and it is timely to be reminded of the importance of conceding the provisional nature of all knowledge and therefore the need to continually test it. (However falsification is only one tool by which we rank knowledge for its worthiness. An hypothesis which has continually survived testing accumulates plausibility with its unavoidable component of confirmation).

Having heard only one side of this experience, we cannot be sure where the diagnostic failure occurred. But as described, the failure was not a neglect of falsification. Rather, it was a failure to adequately consider new information (night back pain)and to recognise the need for a new hypothesis based on existing (albeit indicative only) knowledge that night pain may be a red flag for a more serious cause than stress.

Competing interests: None declared