To understand coherence one must first understand reasoning, and the formal logical elements of inductive and deductive reasoning are instructional for young students learning to understand ways to reasoning. When making a claim and determining whether it stands, a student can use these types of reasoning to test her claim. Inductive reasoning leads to a probable conclusion by weighing available premises. For example, let’s assume that a man watches a weather forecast on Tuesday that predicted rain on Wednesday, and on Wednesday morning he takes an umbrella with him to work. The premise, the expertise and prediction of the meteorologist, leads him inductively to the probable conclusion that it would rain. And so, to avoid getting wet, he takes an umbrella the following morning. Turning this into a metaphor, we could say that Inductive Reasoning is Reading a Map (forecast). By understanding the symbols and markings of the map, we are able to anticipate what will follow.
Deductive reasoning contrasts with inductive reasoning in that it looks backward as opposed to forward. Let’s assume that the same man we mentioned before left his home in the morning and did not come home until early evening. When he comes home, he discovers that the grass is wet. He knows he did not have his sprinklers scheduled, he did not notice any sign of a broken water main on his drive, but he does remember the weather forecast from the night before. By deducting the possible causes of wet grass, the man will deductively arrive at the conclusion that it must have rained while he was away, although much of his reasoning will be done at the subconscious level. Turning this into a metaphor, we could say that Deductive Reasoning is Elimination. By eliminating any invalid premises, we are able to arrive at a (probable) conclusion.
In the same way that these types of reasoning help us sort through experience and plan action each day, they will also help students to test and qualify the claims presented in their own papers. Understanding the moving parts of these terms via metaphor will allow students to apply them to their experience as well as their writing. My hypothesis here is that teaching logical reasoning through the use of metaphorical expression will help students unfamiliar with the terminology of logic to understand its role in founding an argument.