Marlow's encounter with Kurtz may be regarded as the culminating point of Marlow's understanding of the nature of man because throughout this journey Marlow has experienced many different sides to different things all around him, including Kurtz himself. I do not think a person could learn or have an opinion about something unless they have seen both sides of it. This story is very concerned with both the evil of man in his essential nature and the disease of modern, social man to show both aspects of this idea.