Comment by decentrality

The argument is made that evolution is based on a light-dark cycle, but is also based on predators who prefer to catch prey asleep. Survival favored those who could awaken and stay awake until a threat has passed or until sustenance was secure. Sleep is often a luxury, and not due to unhealthy life always. And often we are entranced by what we are doing, living our dreams. Sleep is personal and largely subjective, there is no universal truth on it as long as we all have different lives.