It was a metaphor. It's not meant to be literal. It helps to prompt questions like -- "why do we create the fiction that every job from janitor, to scientist to marketing requires precisely 40 hrs per week, every week?" It also helps explore ideas like, "if I got an illness and could only work one hour a day to keep my business running, how would I do it?" In other words, it's helpful to exlore our use of time.