Robert, imagination is the smoke in which unconscious motives emerge as images. The question I'm trying to answer is, Why were Europeans fascinated by Africa? Why was Marlow there? The answer as I see it is that African culture is the Dionysian complement to the European Apollonian. Marlow was as much under the spell as was Kurtz. The power of the spell comes from unrecognized psychological needs. Even with the disease, brutality, irrationality, the stench and flies -- Africa is a thing of beauty, and the people too. The mythic is usually gory. Part of the irony in Marlow's 'pilgrims vs. cannibals' is that Christianity is a religion of symbolic cannibalism.
Yes, self knowledge is disclosed through imagination, but this is meditation after the event -- like on a yawl at night with an evocative atmosphere. "When it's dark enough, we can see the stars" (Emerson).
I agree, Robert, that there is salvation through imaginative reconstruction of tragedy. The Heart of Darkness transmutes the sufferings of Africa as Illiad and Odyssey do the sufferings of Troy. And I still believe that Penelope would feel less despair in tragedy if she would cook something creative -- put herself into it
-- for her friends. Worked for Jesus.