Light v. Dark
In Marlow’s and the narrator’s eyes, everything that is light is viewed as something positive and the things that are dark are portrayed as malignant. As the Nellie sets on its voyage in the immutable sea, the unnamed narrator looks back at London and view it with such a negative connotation. When he looks back he says, “The air was dark above the Gravesend, and farther back still seemed condensed into a mournful gloom, brooding motionless over the biggest, and greatest, town on earth” and but “it was difficult to realize his work was not out there in the luminous estuary, but behind him, within the brooding gloom.” As they set their eyes with what lays beyond to their destination the setting becomes lighter and presents itself with optimism.
Civilization v. Savagery
The state of being civilized is defined by conforming and abiding by laws to keep order. In Heart of Darkness its illustrated that one of the Belgians excuse to go imperialize Africa was that they were going to “civilize” the natives there but instead what Marlow saw was bloodshed. As Marlow says his farewells to his aunt she is oblivious to what really happens on the other side. She thinks that the Belgians are there to aid the “savages” into formal society, “weaning those ignorant millions form their horrid ways.” In many ways those who claim to be civilized, the Belgians, in reality act like barbarians themselves. They are only there for gaining power and wealth and are treating the natives brutally. They are enslaving, exploiting and killing the Africans and the Belgians themselves are acting depraved towards those they refer to as “savages.” London can also be viewed as once enlightened because as Marlow said they were once found under darkness and were then “civilized” by the Romans.