With the emergence of the Social Darwinism and the expansion to the West of the United States, many people were inclined to believe that if one wants to survive, one must become the fittest of them all. This philosophy of aggressive individualism flourished and became widely recognized in the United States. However, while realists fanatically pursued this Social Darwinism, idealists disdained the idea and insisted that it is not physical aspects that is needed for one’s survival, but rather spiritual aspects such as maintaining one’s humanity and morality that is required for one’s soul is immortal. Noticing this widespread phenomenon, Jack London, a famous American litterateur, wrote The Sea-Wolf in response and depicts Humphrey’s revolt against the rule of Wolf Larsen to reveal that humans needs both morality and physical abilities to survive.

At the beginning of the story, London arranges an encounter between Wolf Larsen, the emblem of realism, and Humphrey Van Weyden, the symbol of idealism, on the Ghost to foreshadow the coming conflicts between the two beliefs. Larsen, the captain of the Ghost, transforms the vessel into his kingdom, where laws and ethics lose their functions, imposing his principles on all crew members: the fittest endure, and human lives are worth less than a penny. Under the suppression of Larsen, all crew members fight only for one goal: survival. For Humphrey, a man who has lived on his parents’ fortune and grew up as a gentleman with manners, life on the Ghost compels him to accept the realism concept. However, Humphrey still holds onto the idealistic idea that the human soul is immortal. To dissuade him of such a belief, Larsen uses his vigorous body to afflict physical violence on Humphrey and forces Humphrey to work endlessly, mocking the contradiction between Humphrey’s desire for physically survive and his insistence of the immortal soul. London uses the juxtaposition of unconscious desire with conscious belief to prove that no matter how firm a soul is, it can never omit the natural lust of physical survival. On the other hand, to survive with good reputation and respect, having only physical strength is not enough; it must be accompanied by humanity.

After multiple interactions with Larsen, Humphrey admits that he fights for the survival, and his insistence of humanity gradually collapses. Nevertheless, Maud, an educated and beautiful female writer, accidentally arrives on board of the Ghost, and her lovely nature emancipates Humphrey’s humanity from the prison of extreme realism. Being an idealist, Maud believes in the immortal soul and the power of humanity. Sharing the similar opinions on critical values with Maud, Humphrey falls in love instantly with Maud; yet, he cannot reveal his feelings to her due to the existence of Larsen, who is stronger than him and wants Maud to become his property. Supported by love, Humphrey retorts Larsen’s words and atrocity. Several times, these confrontations escalate and Humphrey contemplates killing Larsen, but Maud’s begging and his desire to save her from the Ghost stop him. Therefore, Humphrey and Maud furtively escape from the vessel one night. Before Maud’s arrival, Humphrey was not brave enough to escape; however, London depicts the change in Humphrey to indicate the power of love. Influenced by Maud’s and Larsen’s survival philosophies, Humphrey is no longer confused; he combines both of them and becomes a man with both humanity and physical strength, representing London’s own perspective on life.
After floating on the ocean and bearing the cold temperature, Maud and Humphrey finally arrive at Endeavor Island, an unexplored area full of seals. There, Humphrey must protect Maud and overcome the difficulties the severe environment presents. Challenging the impossible, Humphrey uses his love to furnish him with infinite power, which trains him both physically and mentally. He learns how to kill seals, light a fire, and build a hut. However just as everything seems to proceed on the right track, the Ghost emerges at the island. Desperate and frightened, Humphrey sneaks onto the vessel and observes Wolf Larsen standing alone on the ship. He soon realizes tyrant Larsen's mates betrayed him due to the attack and temptation from Larsen’s enemy, Death Larsen. Moreover, Humphrey notes that Larsen is lonely and is so sick that he is losing gradually his senses. Although Humphrey can seek his revenge on Larsen, he chooses to take care of the dying tyrant. Through this scene, the author reveals the transition of the dominant position: both physically and mentally strong, Humphrey is now more potent than Wolf Larsen, who immersed himself in wild Social Darwinism.

At the end of the novel, Maud and Humphrey successfully rescue themselves from the world composed of merely Social Darwinism, while Wolf Larsen, still stubbornly clinging onto his rules, carries his philosophy to rest on the seafloor forever. Beginning as a weak figure, Humphrey gradually obtains the physical strength throughout the journey, and eventually defeats Larsen, the emblem of ultimate human in fitness. Jack London unveils that with the power of humanity and fitness, people can survive in satisfactory conditions and conquer impossible challenges.