Why we still have 8-hour workdays
Observation
The 8-hour day was negotiated for factory shift work in the early industrial era. Knowledge work output is not linear in hours, yet the unit of employment remains the hour-block.
Narrative
Eight hours is the natural and necessary shape of a working day.
Alternative View
The 8-hour day may persist because it is easy to administer and signal, not because it matches how cognitive work is produced.
Unknowns
What does sustained deep-work capacity per day actually average? What coordination value does synchronised presence provide? What happens to output when firms drop hours accounting entirely?
Question
If you were designing work from scratch today, would the hour be the unit?
Why It Matters
An inherited factory constraint silently shapes commuting, childcare, cities and software.