Explaining Why

"Why?" may be the question most commonly asked by human beings. We are fascinated by the reasons for everything we experience in life. We ask questions about natural phenomena: Why is the sky blue? Why does a teakettle whistle? Why do some materials act as superconductors? We also find human attitudes and behavior intriguing: Why is chocolate so popular? Why do some people hit small leather balls with big sticks and then run around a field stomping on little white pillows? Why are America's farms economically depressed? Why did the United States go to war in Vietnam?

Explaining why something occurs can be the most fascinating — and difficult — kind of expository writing. Answering the question "why" usually requires analyzing cause-and-effect relationships, but the causes maybe too complex or intangible to identify precisely. We are on comparatively secure ground when we ask why about physical phenomena than can be weighed, measured, and replicated under laboratory conditions. Under those conditions, we can determine cause and effect with precision. Fire, for example, has three necessary and sufficient causes: combustible material, oxygen, and ignition temperature. Without each of these causes, fire will not occur (each cause is "necessary"); these three causes are, taken together, enough to cause fire (all three are "sufficient"). The cause-and-effect relationship, in this case, can be illustrated by an equation:

• cause 1: combustible substance
• cause 2: oxygen
• cause 3: ignition temperature
• effect: fire

Analyzing both necessary and sufficient causes is essential to explaining an effect. You may say, for example, that wind shear (an abrupt downdraft in a storm) "caused" an airplane crash. In fact, wind shear may have helped cause the crash (been necessary), but by itself wind shear was not the total (sufficient) cause of the crash: An airplane with enough power may be able to overcome wind shear forces in certain circumstances. An explanation of the crash is not complete until you analyze the full range of necessary and sufficient causes, which may include wind shear, lack of power, mechanical failure, and even pilot error.

Sometimes, explanations for physical phenomena are beyond our analytical powers. Astrophysicists, for example, have good theo¬retical reasons for believing that black holes cause gigantic gravita¬tional whirlpools in outer space, but they have difficulty explaining why black holes exist — or whether they exist at all.

In the realm of human cause and effect, determining causes and effects can be as tricky as explaining why black holes exist. Why do some children learn math easily, while others fail? What effect does failing at math have on a child? What are necessary and sufficient causes for divorce? What are the effects of divorce on parents and children? You may not be able to explain all the causes or effects of something, but you should not be satisfied until you have considered a wide range of possible causes and effects. Even then, you need to qualify or modify your statements, using such words as^might," "Usually," "often," "seldom," "many," or "most," and then giving as much support and evidence as you can.

In the following paragraphs, Jonathan Kozol, a critic of America's educational system and author of Illiterate America, explains the multiple effects of a single cause: illiteracy. Kozol supports his explanation by citing specific ways that illiteracy affects the lives of people.

Illiterates cannot read the menu in a restaurant.

They cannot read the cost of items on the menu in the window of the restaurant before they enter.

Illiterates cannot read the letters that their children bring home from their teachers. They cannot study school department circulars that tell them of the courses that their children must be taking if they hope to pass the SAT exams. They cannot help with homework. They cannot write a letter to the teacher. They are afraid to visit in the classroom. They do not want to humiliate their child or themselves...

Many illiterates cannot read the admonition on a pack of cigarettes. Neither the Surgeon General's warning nor its reproduction on the package can alert them to the risks. Although most people learn by word of mouth that smoking is related to a number of grave physical disorders, they do not get the chance to read the detailed stories which can document this danger with the vividness that turns concern into determination to resist. They can see the handsome cowboy or the slim Virginia lady lighting up a filter cigarette; they cannot heed the words that tell them that this product is (not "may be") dangerous to their health. Sixty million men and women are condemned to be the unalert-ed, high-risk candidates for cancer...

Illiterates cannot travel freely. When they attempt to do so, they encounter risks that few of us can dream of. They cannot read traffic signs and, while they often learn to recognize and to decipher symbols, they cannot manage street names which they haven't seen before. The same is true for bus and subway stops. While ingenuity can sometimes help a man or woman to discern directions from familiar landmarks, building, cemeteries, churches, and the like, most illiterates are virtually immobilized. They seldom wander past the streets and neighborhoods ij they know. Geographical paralysis becomes a bitter metaphor for their I! entire existence. They are immobilized in almost every sense we can imagine. They can't move up. They can't move out. They cannot see beyond.