Longer essays may also contain an introductory page that defines words and phrases of the essay's topic. Most academic institutions require that all substantial facts, quotations, and other porting material in an essay be referenced in a bibliography or works cited page at the end of the text. This scholarly convention helps others (whether teachers or fellow scholars) to understand the basis of facts and quotations the author uses to support the essay's argument and helps readers evaluate to what extent the argument is supported by evidence, and to evaluate the quality of that evidence. The academic essay tests the student's ability to present their thoughts in an organized way and is designed to test their intellectual capabilities.
It might be contended, of course, that the attitude to the African in Heart of Darkness is not Conrad's but that of his fictional narrator, Marlow, and that far from endorsing it Conrad might indeed be holding it up to irony and criticism. Certainly Conrad appears to go to considerable pains to set up layers of insulation between himself and the moral universe of his history. He has, for example, a narrator behind a narrator. The primary narrator is Marlow but his account is given to us through the filter of a second, shadowy person. But if Conrad's intention is to draw a cordon sanitaire between himself and the moral and psychological malaise of his narrator his care seems to me totally wasted because he neglects to hint however subtly or tentatively at an alternative frame of reference by which we may judge the actions and opinions of his characters. It would not have been beyond Conrad's power to make that provision if he had thought it necessary. Marlow seems to me to enjoy Conrad's complete confidence -- a feeling reinforced by the close similarities between their two careers.