When doctors knew nothing and could do even less (if actively harming patients with their treatment counts as doing less than nothing), they hid their ignorance and therapeutic impotence by the use of impressive-sounding Latin terminology. Even when they spoke in the vernacular, they did their best to be incomprehensible, and generally succeeded. Portentousness was then a substitute for prowess.
Doctors are still inclined to use impressive-sounding words for the same purpose: or at any rate, so their critics say. Idiopathic is a learned way of saying that the cause of a disease is unknown; and when a disease is said to be multifactorial in causation, it is an implicit avowal of ignorance: for diseases should at least have necessary causes if doctors can claim to understand them.
Actually, most diseases are multifactorial: necessary conditions of causation in medicine are common, while sufficient conditions are rare. For example, the presence of the tubercle bacillus is a necessary condition for the development of tuberculosis, but not sufficient. Many are the people who are infected who do not get the disease.
An ill-understood condition that is thought nevertheless to be bacterial in origin is noma, or cancrum oris. This is a horrible disease that starts as an infected gum and then eats away a large part of the face, killing the patient or leaving him deformed for life. It now affects mainly children in Africa, but it once occurred in Europe and America and was common in the victims of German concentration camps during the Second World War.
Its cause is unknown, unless extreme poverty and malnutrition can be accepted as causes. Nevertheless, these are an insufficient explanation of the disease because, even in severely impoverished conditions, most people do not get it.
A Swiss group, working in a confined area of Niger, a Sahelian country that was once a French colony and that supplies the uranium from which France generates three quarters of its electricity, tried to find the cause of noma, that is to say a bacterially necessary precondition for its development, by comparing 82 children who suffered from it with over 300 matched control who did not. In summary, they failed to do so as have others before them, though certainly not for lack of trying. Their report of their efforts appears in a recent edition of The Lancet.