I'm trying to explain something to someone, but I can't find the right words; I hope some of you can help me. Observations are limited by the instruments available to a scientist. For example, before invention of the microscope, observation of microscopic objects was impossible. In the medical sciences, instrument-limitations plays a significant role. For example, x-rays have limited precision, because beaming too much energy into a patient does more harm than good. And you can't go around cutting every patient open to see what's inside, for obvious reasons. The precision of instruments, while constantly improving, will always be limited. In the field of Medicine, mental disorder is defined officially by the American Psychiatric Association's DSM-IV-TR. Page 485 defines Somatoform Disorder: The APA is saying that a patient has Somatoform Disorder whenever she has symptoms, but doctors are unable to explain why. I find this concept of mental-disorder to be absurd, because it discounts the possibility that a patient is suffering from a general medical condition (e.g., an infectious disease), but the general medical condition is not detectable by the instruments available to the physician. The history of peptic-ulcer-disease confirms the absurdity of this definition of mental-disorder. For decades, researches found no infectious-disease responsible for ulcers; and so for decades, doctors told patients their illness was mental, due to stress. -- http://www.cdc.gov/ulcer/history.htm Peter Moran, one of the researchers involved, recounts, I take issue with the APA's definition of mental disorder, because it discounts the role of doctor and his instruments. If a patient truly is suffering from infectious-disease, but the doctor and his limited instruments fail to identify the infection; the patient is diagnosed as mentally disordered, as advised by the APA. My goal is to describe the absurdity of the DSM's definition of mental-disorder, but using fewer words than I've used here. Any advice or ideas? Thanks.