And to Marlow, it reminds him of a snake bringing the image of evil. Marlow allows his fear to lead him into his new job with great caution. The existentialist idea that "fear drives us" is possibly why Marlow gains a false impression of what his experience will lead him to. With this underlying symbolism, Conrad shows the true intentions of the "noble mission;" usually seen as pure, but is actually full of darkness and corruption. As Marlow travels from the Outer Station to the Central Station and finally up the river to the Inner Station, he encounters examples of torture and cruelty. He sees a group of black prisoners walking along in chains under the guard of another black man. He remarks, "I've seen the devil of violence, and the devil of greed, and the devil of hot desire; but by all the stars! There were strong, lusty, red-eyed devils, that swayed and drove men - men, I tell you. But as I stood on this hillside, I foresaw that in the blinding sunshine of that land I would become acquainted with a flabby, pretending, weak-eyed devil of a rapacious and pitiless folly." (Conrad 14) These devils symbolize the evils of imperialism in Marlow's opinion. The sunshine, although bright and beaming, does not evoke happiness. Instead, Conrad uses light to directly emphasize the dehumanization of the native peoples. .
The African jungle is one of the most predominant symbols for darkness in the story. White Europeans see the jungle as a symbol for primitiveness and savagery; and most readers connect the jungle with a mysterious darkness. As Marlow proceeds deeper into the heart of the African jungle, he realizes that barbarism is an essential part of civilization: "What thrilled you was just the thought of their humanity - like yours - the thought of your remote kinship with this wild and passionate uproar.