"And this also," said Marlow suddenly, "has been one of the dark places of the earth." 

These are the first words that Marlow utters to the group aboard the Nellie as they wait patiently in the River Thames, the sun setting over London. While the narrator views this statement as one that came out of nowhere, its connection to the novella’s title makes it an important clue for the reader, foreshadowing Marlow’s perspective later in the text. He is specifically referring to the fact that the Thames was a site of conquest for the Romans centuries prior, but the idea of London as a “dark place” also speaks to its role as the source of contemporary colonialism. The double meaning inherent in Marlow’s first words implies that he will simultaneously come to recognize the evil inherent in colonization and continue to uphold its legacy.

"It seemed somehow to throw a kind of light on everything about me—and into my thoughts. It was sombre enough too—and pitiful—not extraordinary in any way—not very clear either. No. Not very clear. And yet it seemed to throw a kind of light."

Marlow offers this reflection as he begins to introduce the story of his journey up the Congo River to his listeners, and it serves as a clue to readers that the upcoming narrative will be one of transformation. The “light” metaphor, in which “light” represents newfound knowledge and understanding, emphasizes the extent to which Marlow’s perspective changed as a result of his experiences. This light, however, is “not very clear,” a description which speaks to the impressionistic quality of Marlow’s storytelling as well as his inability to explicitly define how he changed. The murkiness he ascribes to his personal enlightenment suggests that his experiences in the Congo only partially transform his understanding of colonialism.

"You know I hate, detest, and can't bear a lie, not because I am straighter than the rest of us, but simply because it appalls me. There is a taint of death, a flavour of mortality in lies—which is exactly what I hate and detest in the world—what I want to forget."

As he recounts his first conversations with the Brickmaker about Kurtz and Europe, Marlow explains to his listeners that he hates lies. This admission invites a number of questions about his character as the rest of the narrative unfolds. Most notably, Marlow completely rejects this personal philosophy when he blatantly lies to Kurtz’s Intended at the end of the novel. In telling her that Kurtz’s last words were her name and encouraging her belief in his goodness, Marlow not only lies to her but perpetuates the greater lie that colonizers are honorable figures. The contradiction between Marlow’s words and actions also raises broader questions about his reliability as a storyteller, especially given that the novella comes from a literary period characterized by unreliable narrators.