The setting of the frame story in Heart of Darkness just may be the most important setting to discuss in all of great twentieth century literature. (And now that we’ve placed upon ourselves an enormous burden, let’s get started.)
Marlow tells the story of his travels up the Congo River. That makes the setting…the Congo. And more generally, Africa. We get the whole picture from his descriptions – the jungle, the trees, the fog, the scary darkness, the whole nine yards. Sound good?
But then we remember that Marlow is telling us this story…on the Thames in England. Which, much like the Congo, is also a river. It’s almost as if the Thames River is made parallel to the Congo River. And what would that mean? If the Thames is like the Congo, then Europe is like Africa, the white men in England are like the black men encountered in Africa, and Marlow is like Kurtz.
We already have evidence of Marlow being like Kurtz (see the discussion in Marlow's "Character Analysis"). We already decided that Marlow sees himself as similar to the native Africans. And, based on Marlow’s first words ("And this also has been one of the dark places of the earth"), we’ve got a rather solid argument for Europe being like Africa. England, too, was a place of "primitive darkness" until men from Rome (in this scenario, the noble, altruistic "civilized" people invading to do good) rode up and conquered it. Not to mention, if you somehow were unsure by the end of the text, the last line states that the Thames River leads into "the heart of an immense darkness." If you thought the heart of darkness was the interior of Africa, think again.
If Conrad makes this point and successfully draws these parallels, the entire story is imbued with a deeper and more profound meaning. Marlow’s journey into darkness becomes about defining darkness itself; the term evolves into a subjective and relative one, a shifting label. Africa is only dark and primitive for the Europeans trying to conquer it. And what about the darkness in Europe? Marlow even makes the ominous comment that the light they live in now is a "flicker" – that darkness may return to the land soon. Not to mention we haven’t asked just what is darkness, anyway. How "dark" are the native Africans when we consider that Kurtz is the one putting heads on sticks? What if we look for the darkness inside men’s hearts, instead of the literal darkness at the geographical heart of a country? Once we establish with the setting that the Thames is like the Congo, anything is up for debate. We don’t know about you, but we pretty much think that Conrad is the coolest guy ever for coming up with this.