Four hours is the ceiling

The biological ceiling on serious cognitive work is roughly four hours a day. Elite performers in music, chess, and sport converge on it in the lab; the great writers and scientists of the historical record landed on the same ceiling on their own.

The distinguished bodies of work in the historical record were produced, almost without exception, by people who deliberately did less per day than today’s norm.

Software cannot push past the ceiling. It can only burn you against it.