It's the only way to create the divisions between "labor" and "leisure" hours needed for constructing basic utility curves and production functions, and really

It's the only way to create the divisions between "labor" and "leisure" hours needed for constructing basic utility curves and production functions, and really the only way to apply "math" and measurement to what would otherwise just amount to philosophy or sociology. Agreed it's somewhat arbitrary and rigid but pretty necessary for making economic decisions and yeah, a division that is hard to cultivate at the personal level - the hours you spend "working" are also shaping you as a person.