Induction

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Induction vs. Deduction

de·duc·tion (dĭ-dŭk′shən)
1. The process of reasoning in which a conclusion follows necessarily from the premises; reasoning from the general to the specific.
2. A conclusion reached by this process.
Usage The logical processes known as deduction and induction work in opposite ways. When you use deduction, you apply general principles to specific instances. Thus, using a mathematical formula to figure the volume of air that can be contained in a gymnasium is applying deduction. Similarly, you use deduction when applying a law of physics to predict the outcome of an experiment. By contrast, when you use induction, you examine a number of specific instances of something and make a generalization based on them. Thus, if you observe hundreds of examples in which a certain chemical kills plants, you might conclude by induction that the chemical is toxic to all plants. Inductive generalizations are often revised as more examples are studied and more facts are known. Certain plants that you have not tested, for instance, may turn out to be unaffected by the chemical, and you might have to revise your thinking. In this way, an inductive generalization is much like a hypothesis.