What Is Inductive Reasoning?
Inductive reasoning begins with specific observations (or evidence) and goes on to draw a general conclusion. You can see how induction works by looking at the following list of observations:
Nearly 80 percent of ocean pollution comes from runoff.
Runoff pollution can make ocean water unsafe for fish and people.
In some areas, runoff pollution has forced beaches to be closed.
Drinking water can be contaminated by runoff.
More than one third of shellfish growing in waters in the United States are contaminated by runoff.
Each year, millions of dollars are spent to restore polluted areas.
There is a causal relationship between agricultural runoff and water-
borne organisms that damage fish.
After studying these observations, you can use inductive reasoning to reach the conclusion that runoff pollution (rainwater that becomes polluted after it comes in contact with earth-
138
Children learn about the world by using inductive reasoning. For example, very young children see that if they push a light switch up, the lights in a room go on. If they repeat this action over and over, they reach the conclusion that every time they push a switch, the lights will go on. Of course, this conclusion does not always follow. For example, the light bulb may be burned out or the switch may be damaged. Even so, their conclusion usually holds true. Children also use induction to generalize about what is safe and what is dangerous. If every time they meet a dog, the encounter is pleasant, they begin to think that all dogs are friendly. If at some point, however, a dog snaps at them, they question the strength of their conclusion and modify their behavior accordingly.
Scientists also use induction. In 1620, Sir Francis Bacon first proposed the scientific method—a way of using induction to find answers to questions. When using the scientific method, a researcher proposes a hypothesis and then makes a series of observations to test this hypothesis. Based on these observations, the researcher arrives at a conclusion that confirms, modifies, or disproves the hypothesis.
REACHING INDUCTIVE CONCLUSIONS
Here are some of the ways you can use inductive reasoning to reach conclusions:
Particular to general: This form of induction occurs when you reach a general conclusion based on particular pieces of evidence. For example, suppose you walk into a bathroom and see that the mirrors are fogged. You also notice that the bathtub has drops of water on its sides and that the bathroom floor is wet. In addition, you see a damp towel draped over the sink. Putting all these observations together, you conclude that someone has recently taken a bath. (Detectives use induction when gathering clues to solve a crime.)
General to general: This form of induction occurs when you draw a conclusion based on the consistency of your observations. For example, if you determine that Apple Inc. has made good products for a long time, you conclude it will continue to make good products.
General to particular: This form of induction occurs when you draw a conclusion based on what you generally know to be true. For example, if you believe that cars made by the Ford Motor Company are reliable, then you conclude that a Ford Focus will be a reliable car.
Particular to particular: This form of induction occurs when you assume that because something works in one situation, it will also work in another similar situation. For example, if Krazy Glue fixed the broken handle of one cup, then you conclude it will probably fix the broken handle of another cup.