According to Chapter 17, what is the true purpose of human life, and what motivates a person to pursue it?

Chapter 17 defines the true purpose of human life, or Purushartha, as the conscious act of discarding Preya (the pleasant) to honor Shreya (the good). This choice requires firm human effort and a strengthened intellect. The motivation to undertake this difficult path often arises from suffering. The chapter describes how the unfathomable wheel of worldly existence, or Samsara, causes individuals to suffer from the three unendurable torments (Tritapa). As mentioned in Chapter 17, it is only after being exhausted by this extreme sorrow that a person begins to search for a way to stop the cycle, leading to the birth of true manhood (Purushartha) and the choice of means for one's own true self-interest.