We are treating here of cases in which, as one might roughly put it, the grammar of a word seems to suggest the “necessity” of a certain intermediary
stage
step
, although in fact the word is used in cases in which there is no such intermediary step. Thus we are inclined to say, “A man must understand an order before he obeys it”, “He must know where his pain is before he can point to it”, “He must know the tune before he can sing it”, & such like.)