jkgrossi said:
Sure... I understand all that, and am sort of a "productivity geek" myself! I just have to take a step back sometimes and ask myself (when presented with questions such as this one) at what point is it "too much".
The answer is elusive because it's the wrong question. The implication of this thread is that people who sleep half as much are twice as productive rather than half as awake. I defy anyone to provide evidence, beyond dubious anecdotal testimonies like Trump's, that people who sleep less accomplish more.
I used to work in the film industry, on movie sets where 12-to-18-hour days are common. What I observed for the most part were crew members "forgetting" instructions, asking to have things repeated, looking at their watches, griping, arguing, etc. The same scene that would be shot in 4 takes at the beginning of the day might need 10 takes in the 12th hour. This counterproductivity was obvious to everyone except to the producers and directors, who were obsessed with milking every drop of labor the could get, even if the speed and quality of the labor suffered.
I think that the quality of those "extra four hours" being coveted here will inevitably be of the type that, in a more racist era, was called "CP time," or "colored people time." Having no ability to openly disobey their "owners," slaves would often execute their tasks as inefficiently as possible in silent protest. The same principle applies on an intrapersonal level: yes, it's possible to look busy for four more hours, and it might even massage your vanity. But your body and unconscious will resent it and deprive you of the energy needed to make the longer transaction worthwhile.
jkgrossi, I realize your question is more fundamental: Is the point of life to be more productive? But since this thread emerged in the context of increasing productivity, I'm arguing that, even on that debatable standard, sleep deprivation is counterproductive.