In Heart of Darkness, Joseph Conrad probes the hypocrisy of colonialism and the quest for truth.

Colonialist efforts in the 19th century were justified by Europeans as an effort to improve both European and native communities. It was justified as an effort to bring wealth to Europe and civilization to the “savages” who inhabited the colonies. In particular, great eloquence was dedicated to the latter justification. Europeans stated that it was “the White man’s burden” to educate, purify, and elevate the status of native people in the colonies. According to this logic, rather than infringing on the self-government and liberty of the colonies, Europeans were helping indigenous people improve their societies. Heart of Darkness pierces through this moral veneer by presenting the detrimental effects of colonialism. In the novel, Marlow recalls the Eldorado Expedition, which “went into the patient wilderness, that closed upon it as the sea closes over a diver. Long afterwards the news came that all the donkeys were dead. I know nothing as to the fate of the less valuable animals. They, no doubt, like the rest of us, found what they deserved.” Here, Marlow’s narrative removes the gloss that covered colonialism in public imagination. The detrimental effects of colonialism are likewise on full display when Marlow recalls the “lone white man turning his back suddenly on the headquarters, on relief, on thoughts of home—perhaps; setting his face towards the depth of the wilderness, towards his empty and desolate station.” Marlow reveals the pain colonialism bestows upon the colonists when he points out that “the reaches opened before us and closed behind, as if the forest had stepped leisurely across the water to bar the way for our return. We penetrated deeper and deeper into the heart of darkness.” Colonialism is often imagined as the quest for money and glory. Marlow’s narrative presents the alternative. His narrative reveals that colonialism only brings loneliness and isolation. 

The novel also explores an individual’s quest for truth. In the novel, Marlow seeks out Kurtz, the lighthouse figure of European civilization and morality in the middle of the dark, uncivilized jungle. Ironically, Marlow’s quest for truth leads him to the conclusion that truth is simultaneously nowhere and everywhere. Marlow remarks that  “it is impossible to convey the life-sensation of any given epoch of one's existence—that which makes its truth, its meaning—its subtle and penetrating essence. It is impossible. We live, as we dream—alone.” The truth seems to lay in the heart of darkness, which represents nothingness. The ideological construct of truth seems to be obscure, almost irrelevant. It does not seem to pinpoint a specific location or a specific idea. Yet, at the same time, truth also seems simple, tangible. Truth seems to also exist within civilization. Marlow points out that, when the prospect of discovering ivory is brought out among the colonists, “outside, the silent wilderness surrounding this cleared speck on the earth struck me as something great and invincible, like evil or truth, waiting patiently for the passing away of this fantastic invasion.” Here, truth seems to lay in the idea of obtaining ivory. 

Ultimately, Heart of Darkness presents two opposites -- civilization and heart of darkness (nothingness) -- as existing at the same time. Both are true and the truth can be found in both. The novel challenges the audience to look beyond simple dichotomies and to recognize the limit that exists in the popular construct of the existence of polar sides in every situation.