Here’s a random thought.
Disease are pretty much categorized by the symptoms they cause. Because way back in the day when they were first given names, that’s all we had to go by: the way someone looked or acted or felt when they something was wrong with them. But now we know what causes a great many diseases. And in some cases, the same thing – the same genetic fault, or bacteria, or virus, or whatever thing that isn’t right – will be the same for a few very different diseases. Like if you get infected with streptococcus bacteria? You could get strep throat… or you could get the flesh-eating bacteria disease. So in the future, will we switch to categorizing disease by what causes them, or will we stick with symptomatic categories?
Apropos of nothing.