Besides being an existentialist journey into the human soul, Heart of Darkness is also a social commentary. Throughout the novella, Conrad points out social evils in satirical ways. In Heart of Darkness, Conrad draws attention to the social mores of Imperialism, condescension, and greed.
One of the unjust social mores that Conrad criticizes in Heart of Darkness is the two-facedness of European imperialism. The men who work for the Company describe what they do as "trade," and their treatment of native Africans is part of a benevolent project of "civilization." While in reality, they just stole ivory and treated the natives brutally and inhumanely. Conrad used phrases such as "nothing earthly" and "black shadows of disease and starvation" to describe the natives to indicate how the Company callously treated the natives as objects.
Another social attitude that Conrad address in Heart of Darkness is the condescension with which people view others whose cultures they do not understand. One of the ironies of the book is how the "savage" cannibals were able to show restraint while restraint is something unknown to Kurtz. Bedazzled, Marlow "would just as soon have expected restraint from a hyena prowling amongst the corpses of a battlefield." Marlow also treats the natives as inferior objects. For instance, when one of the members of his crew is killed, he is more concerned with his shoes than with the loss of life.
In Heart of Darkness, Conrad also concentrates on the obstacles of personal greed and laziness. The Pilgrims, for instance, all want to be appointed to a station so that they can trade for ivory and earn a commission, but none of them actually takes any effective steps toward achieving this goal. Kurtz, although anything but lazy, in his rapacity, steals and kills for his ivory. The general manager, also guilty of avarice, said "we will not be free from unfair competition until one of these fellows is hanged as an example.