Whose standard argument? I always thought: we work 40 hours a week because we work 8 hours a day; and we work 8 hours a day because Robert Owen's mantra "Eight

Whose standard argument? I always thought: we work 40 hours a week because we work 8 hours a day; and we work 8 hours a day because Robert Owen's mantra "Eight hours' labour, Eight hours' recreation, Eight hours' rest" caught on.