I wasn’t previously aware of this mid-20th-Century medical dispute (subscription required):

Among the most famous controversies in 20th century medicine was the momentous one between Sir George Pickering (1904-80) and Sir Robert Platt (1900-78) over the nature of hypertension: whether high blood pressure was merely one end of a normal distribution, or whether there was a bimodal population, one part of which suffered from the discrete disease called hypertension. The dispute rumbled on for years. It is generally thought that it was Pickering who triumphed in the end, in the process overturning what until then had been the orthodox view. It is not given to mortals, even to doctors, to live without orthodoxies.

Dalrymple praises Pickering’s writing, and one can see why:

The hypothesis [of a continuum in blood pressure and the gradation in risk that it poses] has been greeted by medical scientists “as a glimpse into the obvious,” and by physicians as “dangerous nonsense because it is against established teaching.” It is apparently difficult for doctors to understand because it is a departure from the ordinary process of binary thought to which they are brought up. Is it normal or abnormal, physiological or pathological, health or disease, good or bad? Quantity is not an idea that is as yet allowed to intrude. Medicine in its present state can count up to two but not beyond.