Conrad's greatest illustration in Heart of Darkness is the harsh environment that is created when one man declares his superiority over another. The underlying resemblance to slavery here in the United States in previous ages is a unique and strangely accurate one.
Heart of Darkness also shows such illustrations of the European view of the mentality of these uncivilized natives as on page 58, when speaking of how hungry, starving really, these natives were. He writes, "Why in the name of all the gnawing devils of hunger they didn't go for us- they were thirty to five- and have a good tuck-in for once, amazes me now when I think of it. They were big powerful men, with not much capacity to weigh the consequences, with courage, with strength,.". In the same sentence Conrad mentions courage and strength with "not much ability to weigh the consequences.". It seems that these natives were thought of more as animal than human in the eyes of these British men- precisely the sentiment of the times.
The very nature of the men who traveled to the Congo from Europe is depicted with crystal clarity on page 79 of Heart of Darkness. The narrator is telling a story of a fight in which Kurtz was going to shoot a man. ""What for?" "Well, I had a small lot of ivory the chief of that village near my house gave me. Well, he wanted it, and wouldn't hear reason. He declared that he would shoot me unless he I gave him the ivory and then cleared the country, because he could do so, and had a fancy for it, and there was nothing on earth to prevent him from killing whom he jolly well pleased."" The Englishmen show such superiority over the natives with their organized, capable minds, yet place themselves on the same level by reducing themselves to fighting-even killing- for physical, materialistic things. This is where the darkness within really starts to come out in the story. We see more and more savagery in the characters as their roles develop, and always a sense of preeminence over the uncivilized natives.