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:

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-bound pollutants such as fertilizer, pet waste, sewage, and pesticides) is a problem that must be addressed.

image
Sign warning of contaminated water
© Krista Kennella/ZUMA PRESS

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.