> I assume there is some sort of middle ground between working too much and working too little. Are there any actual evidence that that optimum middle ground is

> I assume there is some sort of middle ground between working too much and working too little. Are there any actual evidence that that optimum middle ground is 4 days and not 3, or 5? That's the problem with this whole thing. People don't have a rationale for it. They just want to work fewer hours. If the 4-day week happens, we will see the same arguments being made for the 3-day week, because there is no actual basis for any of this: people will always want to work fewer hours than they work now.