Here's a profound realization. Utility is a function of both variables, time and money. Wholly unemployed people have plenty time but can't afford to spend the

Here's a profound realization. Utility is a function of both variables, time and money. Wholly unemployed people have plenty time but can't afford to spend the money using it how they want. So the situation is valueless. On the opposite extreme, people who spend every waking working have plenty of money but can't afford to spend a second using it how they want. So that situation is also valueless. Based on nothing more than crudely assuming utility = time*money and then optimizing with simple calculus, you can get very close to deriving a 40 hour work week as the utility maximizing choice.