One central passage in The Old Man in the Sea takes place beginning on page 113, as Santiago reflects on the nature of sin. When he finally kills the marlin that he tracked and wrestled with for three days, Santiago perceives that the "breeze [is] fresh now," which can be read as an instance of pathetic fallacy, marking his hope for his future and self-preservation. But soon, he is taken up by an inner conflict in which his competing desires to survive and to protect the sanctity of life are called into question.
Having called the marlin a "brother" and learned to admire its intrinsic dignity as it fought for its life, Santiago draws the early conclusion that it does not deserve to be eaten. In the fight's aftermath, he fashions a more deterministic argument, concluding that organisms are destined to play out their roles, and he, therefore, has just as much right to eat the fish as the fish did to attempt to save itself. Conceiving of the answer to this moral quandary as commensurate with understanding the true nature of sin, Santiago concedes that he understands little about sin at all.
Santhiago begins to eat the fish, and Hemingway invokes rich imagery of its flesh, which is "firm and juicy... but not red," suggesting an intrinsic difference from the flesh of men. This image stands in for Santhiago's perceived difference in the two creatures' moral universes. Yet, he notes that there is "no way to keep its scent out of the water," implying a cost to his moral judgment: killing the fish incurs the cost of attracting more insidious predators. The end of the passage depicts the breeze as still uncannily steady, with no sign of sails or the "hull nor the smoke of any ship." The inertness of his geographical space suggests that in the lonely space of one's individual moral life, one has no moral authority to confer with or look up to.