Marcus reflects that the “good life” can only be found by “doing what man’s nature requires,” which means “having principles to govern his impulses and actions” (76). The principles are good and evil themselves, the former being what makes a man “just, self-controlled, brave, and free” and the latter the opposite (76). To be fulfilled, all living organisms must follow the path set forth by their natures, whether plant, animal, or human. The former two have neither perception nor reason, but men, who are rational beings, do. Humans are related to their environment, to divine cause, and to their fellow men. God’s gift to man is the ability to remain one with the Whole. Unlike a body whose parts have been severed, a man who has felt himself cut off from the Whole can rejoin it.

Listing Roman leaders and Greek philosophers, Marcus notes that the latter penetrated reality, mastered by “their directing minds” while the former were “slaves to all their ambitions” (72). He exhorts himself to continually test his impressions and blame neither his circumstances nor others for acts that are part of their natures. Everything has a purpose. Everything he does should benefit humanity.