Writing Well

A + B = C: Appeal to Reason

Word Watch

Writing that appeals specifically to reason is often called argumentation.

Appeals based on reason rely on facts rather than on emotion. In turn, each logical argument in your essay must be supported by evidence: facts, statistics, expert testimony, or details about the argument. The basic organization for a persuasive essay or letter developed on a logical argument looks like this:

Here's an example of a logical argument constructed this way. It's in the form of a cover letter to accompany a resumé.

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Remember that a persuasive essay doesn't have to prove a point beyond a shadow of a doubt; it need only convince your readers that your viewpoint is valid and deserves serious consideration.

Logical arguments are developed in two basic ways: inductively or deductively.

Specific to General: Inductive Reasoning

Inductive reasoning draws a logical conclusion from specific facts. It depends on drawing inferences from particular cases to support a generalization or claim. Many of our everyday conclusions are based on inductive reasoning. For example, if three people whose judgment you respect tell you that a particular movie is worth seeing, you'll conclude that the movie is most likely something you'll enjoy. It might even be worth the $8.50 ticket (not counting the popcorn and soda).

Therefore, the success of an essay built inductively depends on the strength of your examples. When it comes to examples in argumentation, more is often better, but space is always a consideration. As a result, you're better off presenting a handful of examples in detail than a pile of proof without much backing. When in doubt, stick with the magical number three: introduction, three examples, conclusion. This gives you a balanced, five-paragraph essay or letter and meets reader expectations.

General to Specific: Deductive Reasoning

Deductive reasoning moves in the opposite direction, from a general premise to particular conclusions. Sometimes, it depends on a logical structure called a syllogism. Here's an example:

Word Watch

A syllogism is a pattern of logical thinking used in deductive reasoning. It has three parts: a major premise, a minor premise, and a conclusion.

If you accept the major premise that all men will eventually kick the bucket and the minor premise that Herman is a man, then you have to accept the conclusion. Most written arguments collapse because the major premise isn't true. The rest of the argument, built on a rickety frame, is bound to crash. Here's an example from Alice in Wonderland:

However, a syllogism can be valid but not true, as in this example:

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Rarely will a writer lay out a deductive argument this neatly, however. In most cases, for example, the first statement will be implied rather than stated.

To use deductive reasoning correctly, first make sure that the major premise is true. If it isn't valid, the rest of the argument will bomb. Then craft a minor premise that logically follows the first one. Finally, decide if the conclusion is sound.

It's not likely that you'll be using formal syllogisms in your writing, but you will be using this method of thinking when you construct an argument deductively. The following excerpt from the Declaration of Independence relies on a deductive pattern to make its argument. See if you can find the major premise. (Hint: It's in the very beginning.)

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Excerpted from The Complete Idiot's Guide to Writing Well © 2000 by Laurie Rozakis, Ph.D.. All rights reserved including the right of reproduction in whole or in part in any form. Used by arrangement with Alpha Books, a member of Penguin Group (USA) Inc.

To order this book direct from the publisher, visit the Penguin USA website or call 1-800-253-6476. You can also purchase this book at Amazon.com and Barnes & Noble.


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