Marlow’s journey up the Congo River is an allegory for Joseph Conrad’s exploration of human nature. After all, the title Heart of Darkness represents both the Congo itself (the remote, inaccessible “heart” of Africa, which is the “dark continent”) and the metaphorical darkness that Conrad sees in the depths of the human soul. The double meaning of Marlow’s voyage is clear from the beginning: Marlow declares that he became a sailor because he was always drawn to the “many blank spaces on the earth”—most of all central Africa, which was “the biggest, the most blank,” a place of “delightful mystery.” While other Europeans seek glory and riches in the Congo, Marlow seeks knowledge and truth. This introduction sets up Marlow’s voyage as an allegory for the human search for meaning: as he pursues his curiosity about Africa, he is also testing out his ideas about himself, human nature, and Europe’s colonial ambitions.
Surely enough, by the end of Marlow’s journey, the brutality of European colonialism has shown him that selfishness and corruption lie at the heart of human nature. Marlow realizes this gradually, as each stage in his journey up the Congo River brings him closer to the truth. For instance, when he first reaches the river mouth, he sees a French ship pointlessly shelling the coast, which suggests that colonialism is futile and absurd. Later, at the Outer and Central Stations, he meets incompetent, passionless men like the Brickmaker and Accountant, who show him that colonialism is soulless, motivated solely by profit and completely indifferent to the value of human life.
Finally, upon reaching the Inner Station, Marlow learns that the legendary Kurtz is not a civilized ivory trader, but rather an insane mercenary who seizes ivory through murder. For the whole novella, Kurtz represents Marlow’s hope that there are noble ideas and good intentions at the heart of colonialism—and, by extension, human nature. But, after pinning his hopes on Kurtz for so long, Marlow must finally admit that he was duped, and that human nature is ultimately governed by nothing but greed and corruption. This is why generations of readers have viewed Marlow’s journey as a representation of Conrad’s ideas about human nature. Anyone who delves into the human soul, Conrad suggests, is likely to find that people’s beliefs and principles are little more than empty excuses for greed and gluttony. Even society, for Conrad, is really just a way for people with power to collectively trample on those without it.
However, generations of readers have also criticized Conrad’s allegory for replicating common, racist European tropes about Africa. Specifically, in Heart of Darkness, Africa becomes a metaphor for human nature (while Europe represents human civilization), and “civilized” Europeans use journeys to Africa to get back in touch with their natural, “primitive” sides. While Conrad did argue that there is no fundamental difference between Europeans and Africans, he still presented Africans as “primitive.” Throughout the book, they are faceless, voiceless, subhuman “savages” and “cannibals.” They lack reason and individuality, and Marlow tends to forget about their suffering as quickly as he can, because he’s too busy thinking about the motivations of white men like himself and Kurtz. Thus, by turning Marlow’s journey to the Congo into an allegory for the human search for meaning and knowledge, Conrad risks ignoring Africans’ humanity—and being just as callous and corrupt as the colonizers he decries.