The owner of a day-care has taken premises four times the size of her present ones. She argues that admissions have doubled in each of the last two years and that a second doubling will fill the new premises and pay the rent on them. Which of the following is an assumption on which the owner's argument depends?

A doubling can go on only while there are people left to double into. If the day-care already takes most of the town's children of that age, the next doubling has nowhere to come from and the past two years' growth is no guide at all — it was the easy climb through an untouched market. Ease of reaching the premises and the helpers' willingness are conditions of running the day-care rather than steps in the argument, and what a competitor has leased neither supplies children nor withholds them from the reasoning.