How does Chapter 8 philosophize about the purpose of human life in contrast to animal existence?

According to the teachings in Chapter 8, the true purpose of human life is the attainment of the Supreme Self (Paramatman). The text poses that if life is spent merely on the four activities of eating, sleeping, fear, and mating, then there is no meaningful difference between a human and an animal like a dog or a pig. The chapter emphasizes that while a dog can fill its belly and reproduce, a human is uniquely free, fearless, and independent, and the true success of this precious birth lies in realizing the Eternal. Without this pursuit, human life is deemed useless.