Read the excerpt from "An Image of Africa: Racism in Conrad’s Heart of Darkness. ” Conrad, after all, did sail down the Congo in 1890 when my own father was still a babe in arms. How could I stand up more than fifty years after his death and purport to contradict him? My answer is that as a sensible man I will not accept just any traveller's tales solely on the grounds that I have not made the journey myself. I will not trust the evidence even of a man's very eyes when I suspect them to be as jaundiced as Conrad's. What type of evidence does Achebe use to support his claim in this passage?