Frederick Crews, The Random House Handbook, Second Edition
An essay can be defined as a brief piece of nonfiction that tries to make a point in an interesting way. Will we be able to write them at all? Looking ahead, perhaps you experience a feeling that assails every writer from time to time – the suspicion that words may fail you. (And if words fail you, your readers may fail you.)
Essay falls into four types, corresponding to four basic functions of prose: description (or picturing); narration (or telling); exposition (or explaining); and argument (or convincing).
A descriptive essay aims to make a place, an object, a character, or a group. The write tries, not simply to convey facts about the object, but to give readers a direct impression of that object, as if they were standing in its presence. The descriptive writer's task, we might say, is one of translation: he (or she) wants to find words to capture the way his (or her) five senses have registered the item, so that a reader of those words will have a mental picture of it.
A narrative essay recounts something that has happened. That something can be as small as a minor personal experience or as large as a way, and the narrator's tone can be either intimate and casual or neutrally objective and solemn. Inevitably, a good part of narration is taken up with describing. But a narrative essay differs from a descriptive one in its emphasis on time and sequence. The essayist turns storyteller, establishing when and in what order a series of related events occurred.
An expository essay is one whose chief aim is to present information or to explain something. To expound is to set forth in detail, so that a reader will learn some facts about a given subject: the climate of Australia, sewage treatment by evaporation, the style of Beethoven's late sonatas, your goals in life. As we have seen, however, no essay is merely a set of facts. Behind all the details lies an attitude, a point of view. In exposition, as in all the other types, details must be selected and ordered according to the writer's sense of their importance and interest. Though the expository writer is not primarily taking a stand on an issue, he (or she) cannot -- and should not try to -- keep his (or her) opinions completely hidden. There is no interesting way of expounding the subject without at least implying a position.
When the writer's position is not implied but openly and centrally maintained, the essay is argumentative. This word may be startling to readers who think of an argument as a quarrel, often involving raised voice and frazzled tempers. That is one common meaning, but not the one that applied to discussions of writing. An argument is simply a reasoned attempt to have one's opinions accepted. Quarrelsomeness need not enter an argumentative essay at all. On the contrary, the essayist who appears to be losing his temper will also appear to be losing the argument. The ideal is to present supporting evidence that points so plainly to the correctness of your stand that you can afford to be civil and even generous toward those who believe otherwise. Much of that supporting evidence will inevitably consist of exposition: you want to show that facts a, b, c, and d oblige any reasonable person to agree with conclusion x. But if you give any of those facts more emphasis than the idea they were meant to prove, you are losing track of the fundamental purpose of argumentation.
In one vital respect argument stands alone among the four types: it is the only one in which there are technically right and wrong methods of proceeding. Quite apart from its truth or falsity, an argument is either valid or in valid (“logical” or “illogical”) according to whether or not the rules of reasoning have been properly observed. If the writer’s conclusion necessarily follows from his or her premises or supporting statements, the argument is valid – whether or not it contains errors of fact. And the argument is invalid if a rule of reasoning has been broken in the process of getting from premises to conclusion. This is not a point of interest to logicians only. Ordinary readers will recognize an invalid argument as weak, even if by good fortune its wrongly derived conclusion happens to be true.
This may sound disheartening, even forbidding. But the logic that applies to essay writing falls entirely within the common sense we all possess. There is no need to memorize a great many abstract rules in order to undertake an argument. The argument should be logical, but it should not display its logic in an arid, self-consciously rule-abiding way. You need only sharpen your awareness of the most usual mistakes in reasoning, and you will be able to compose essays that withstand logical criticism without sounding as if they had been written by a computer.
In practice, it would be difficult to write an essay that drew on just one of the four basic types. Nor would there be much point in trying, since each of the four functions – to picture, to tell, to explain, and to convince – can help to serve any of the others. A typical essay might describe something in order to narrate its part in a historical episode, tell a story to enliven an exposition, or expound something in order to back an argument.