As a fisherman who has caught nothing for the last 84 days, Santiago is a man fighting against defeat. Yet Santiago never gives in to defeat: he sails further into the ocean than he ever has before in hopes of landing a fish, struggles with the marlin for three days and nights despite immense physical pain and exhaustion, and, after catching the marlin, fights off the sharks even when it's clear that the battle against them is hopeless. Whenever the situation gets particularly difficult and despair threatens to overwhelm Santiago, he turns to a number of tactics to fuel his resistance to defeat: he recalls memories of his youthful strength; he relies on his pride by demanding that he prove himself a worthy role model for Manolin or by comparing himself to his hero Joe DiMaggio; and he prays to God, even though his prayers do nothing to ease his physical suffering.
Ultimately, Santiago represents every man's struggle to survive. And just as Santiago's effort to bring the marlin back to land intact is doomed, no man can ever escape death. Yet through Santiago's struggle, Hemingway makes the case that escape from death is not the issue. As Santiago observes near the end of his struggle with the marlin, "a man can be destroyed but not defeated." In other words, victory over the inevitable is not what defines a man. Rather, it a man's struggle against the inevitable, even when he knows it is inevitable, that defines him. And the more difficult the struggle, the more worthy the opponent, the more powerfully a man can prove himself.
Pride is often depicted as negative attribute that causes people to reach for too much and, as a result, suffer a terrible fall. After he kills the first shark, Santiago, who knows he killed the marlin "for pride," wonders if the sin of pride was responsible for the shark attack because pride caused him to go out into the ocean beyond the usual boundaries that fishermen observe. Santiago immediately dismisses the idea, however, and the events of The Old Man and the Sea support his conviction that pride is not the cause of his difficulties.
In fact, Santiago's pride is portrayed as the single motivating force that spurs him to greatness. It is his pride that pushes him to survive three grueling days at sea, battling the marlin and then the sharks. Yet it is important to recognize that Santiago's pride is of a particular, limited sort. Pride never pushes him to try to be more than he is. For instance, when Manolin tells him, "The best fisherman is you," early in the story, Santiago humbly disagrees. Rather, Santiago takes pride in being exactly what he is, a man and a fisherman, and his struggle can be seen as an effort to be the best man and fisherman that he can be. As he thinks in the middle of his struggle with the marlin, he must kill the marlin to show Manolin "what a man can do and what a man endures." Santiago achieves the crucial balance between pride and humility—that "[humility] was not disgraceful and it carried no true loss of pride."
The friendship between Santiago and Manolin plays a critical part in Santiago's victory over the marlin. In return for Santiago's mentorship and company, Manolin provides physical support to Santiago in the village, bringing him food and clothing and helping him load his skiff. He also provides emotional support, encouraging Santiago throughout his unlucky streak. Although Santiago's "hope and confidence had never gone," when Manolin was present, "they were freshening as when the breeze rises." And once he encounters the marlin, Santiago refuses to accept defeat because he knows Manolin would be disappointed in him.
Yet most of the novella takes place when Santiago is alone. Except for Manolin's friendship in the evenings, Santiago is characterized by his isolation. His wife has died, and he lives and fishes alone. Even so, just as he refuses to give in to death, he refuses to give in to loneliness. Santiago finds friends in other creatures. The flying fish are "his principal friends on the ocean," and the marlin, through their shared struggle, becomes his "brother." He calls the stars his "distant friends," and thinks of the ocean as a woman he loves. Santiago talks to himself, talks to his weakened left hand, and imagines Manolin sitting next to him. In the end, these friendships—both real and imagined—prevent Santiago from pitying himself. As a result, he has the support to achieve what seems physically impossible for an old man.
The title of the novella, The Old Man and the Sea, suggests the critical thematic role that age plays in the story. The book's two principal characters, Santiago and Manolin, represent the old and the young, and a beautiful harmony develops between them. What one lacks, the other provides. Manolin, for example, has energy and enthusiasm. He finds food and clothing for Santiago, and encourages him despite his bad luck. Santiago, in turn, has wisdom and experience. He tells Manolin stories about baseball and teaches him to fish. Santiago's determination to be a good role model for Manolin is one of his main motivations in battling the marlin for three days—he wants to show Manolin "what a man can do."
Santiago's age is also important to the novella because it has made him physically weak. Without this weakness, his triumph would not be so meaningful to him. As Santiago says, he "had seen many [fish] that weighed more than a thousand pounds and had caught two of that size in his life, but never alone" and never as an old man. Santiago finds solace and strength in remembering his youth, which is symbolized by the lions on the beach that he sees in his dreams. He recalls these lions—slow, graceful but fierce creatures—from the perspective of an old man. In doing so, he realizes that he too, although slow, can still be a formidable opponent.
Since The Old Man and the Sea is the story of a man's struggle against a marlin, it is tempting to see the novella as depicting man's struggle against nature. In fact, through Santiago, the novella explores man's relationship with nature. He thinks of the flying fish as his friends, and speaks with a warbler to pass the time. The sea is dangerous, with its sharks and potentially treacherous weather, but it also sustains him by providing food in the form of dolphins and shrimp. Finally, Santiago does not just see the marlin as an adversary, he loves it as a brother. In the middle of their struggle, Santiago says to the marlin, "Come on and kill me. I do not care who kills who." Santiago's statement shows the depth of his admiration for the marlin and hints at the fundamental law of nature that unites man and animal: all beings must die, must kill or be killed. In this way, man and nature are joined in a circular system, in which death is necessary and fosters new life.
The Old Man and the Sea is full of Christian imagery. Over the course of his struggles at sea, Santiago emerges as a Christ figure. For instance: Santiago's injured hands recall Christ's stigmata (the wounds in his palms); when the sharks attack, Santiago makes a sound like a man being crucified; when Santiago returns to shore he carries his mast up to his shack on his shoulder, just as Christ was forced to bear his own crucifix; and Santiago's final position, resting on his bed, resembles Christ's position on the cross. More importantly, Santiago resembles Christ in that, like Christ, he transforms loss into triumph, faces the inevitability of death without complaint and, in doing so, transcends it. Christ literally is resurrected, while Santiago regains Manolin as an apprentice, providing both the companionship he had lost and the chance to pass his knowledge on to the next generation.