My father had no interest in the things in the kitchen, and had never cooked himself. When Mother was ill, however, he volunteered to go to the supermarket for her. She sent him off with a carefully numbered list of seven items.
Dad returned shortly, very proud of himself, and proceeded to unpack the grocery bags. He had one bag of sugar, two dozen eggs, three hams, four boxes of detergent, five boxes of crackers, six eggplants, and seven green peppers.
With no experience of having cooked himself, he didn’t have even a rough idea of the necessary quantity of each item. At the supermarket, he saw the figure one placed right before sugar. It was the only clue as to the quantity he could find on the paper. Convinced that it meant the required quantity of sugar, he put a bag of sugar in the shopping cart. How could he have figured out that the figure was only the item number and it had nothing to do with the quantity? He followed the same process for the remaining six items as well, resulting in each item in the cart by the quantity indicated by the figure at the head of each list. From his point of view, Dad had accomplished precisely what Mother had instructed him to do.