How does Chapter 8 portray the different stages of a typical human life and the passage of time?

Chapter 8 presents a somber view on how human life is often wasted. It states that days rise and set while years are consumed, with half of life spent in sleep and the remainder in restlessness. The chapter details how each stage is squandered: childhood is spent in play, youth is consumed by passion for women, and old age is burdened by infirmity and constant disease. It uses the metaphor of a lamp flame, which looks the same but is different every moment, to describe the body's constant, unnoticed change through childhood, youth, and old age, highlighting the transient nature of existence.