According to the provided text, what is the true purpose of human life, and how does it differ from mere survival?

The text from Chapter 8 posits that the true duty and success of human birth is the attainment of the Supreme Self (Paramatman). It sharply contrasts this higher purpose with mere biological existence. The chapter questions the value of a life spent only on basic needs by asking what dogs and pigs lack in terms of survival. It argues that if life is reduced to the four activities of eating, sleeping, fear, and mating, or if nourishing the body and sexual pleasure are its only ends, then the human birth is rendered useless. True greatness for a human, who is described as free and fearless, lies in the realization of the Eternal, not in functions that animals also perform.