Writing Well: A + B = C: Appeal to Reason

A + B = C: Appeal to Reason

  • Whether our argument concerns public affairs or some other subject, we must know some, if not all, of the facts about the subject on which we are to argue. Otherwise, we can have no materials out of which to construct arguments.
  • —Aristotle, Rhetoric
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:

  • Introduction. Catches the reader's attention and states your argument. Includes a concise statement of your position on an issue that will interest your readers.
  • Body. States each logical argument by presenting supporting evidence. Disarms the opposition, establishes the writer's credibility, and sets an effective tone.
  • Conclusion. Restates your argument and summarizes your main points.

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

  • 3 Covered Bridge Road
    Los Angeles, CA 90039
  • April 4, 2000
  • Mr. Juan Perez, Manager
    Fox Hollow Inn
    1414 Jericho Turnpike
    Los Angeles, CA 90039
  • Dear Mr. Perez:
  • I am writing in response to the advertisement you placed in Sunday's Los Angeles Times for a part-time matre d'htel at the Fox Hollow Inn. Next year, I will receive my degree in Restaurant Management from the Culinary Arts Institute. I believe that both my education and experience are directly related to your needs.
  • As a junior, I have taken many courses in Restaurant Management and have earned a B+ average in my major. As a result, I have a great deal of formal instruction in running a restaurant efficiently. I can perform most dining room procedures skillfully, especially serving as a welcoming and efficient host. Last month, I was named “Junior Man of the Year” for Restaurant Management, in recognition of my hard work and accomplishments.
  • Besides taking courses in this field, I have years of hands-on experience. For the past two years, I have been working at the campus restaurant, the Fireside Lounge. In this capacity, I have been a line cook, server, and matre d'htel. This year, I organized the annual Wine and Cheese Party (a benefit for the Heart Fund) as well as staffing dozens of major receptions and parties.
  • I would welcome the opportunity to join your staff because you enjoy a reputation for helping students gain experience in the industry. I am enclosing my resum and am available for an interview at your convenience.
  • Sincerely,
  • Matt Ling
  • enc.
Write Angles

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.

  • Major premise: All men are mortal.
  • Minor premise: Herman is a man.
  • Conclusion: Therefore, Herman is mortal.

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:

  • “Very true,” said the Duchess: “flamingoes and mustard both bite. And the moral of that is—Birds of a feather flock together.”
  • “Only mustard isn't a bird,” Alice remarked.
  • “Right, as usual,” said the Duchess. “What a clear way you have of putting things!”

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

  • Major premise: Ten chefs can cook faster than one chef.
  • Minor premise: One chef can make a souffl in an hour.
  • Conclusion: Therefore, 10 chefs can make a souffl in six minutes.
Write Angles

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.)

  • When in the course of human events, it becomes necessary for one people to dissolve the political bands that have connected them with another, and to assume among the powers of the earth, the separate and equal station to which the laws of nature and of nature's God entitle them, a decent respect to the opinions of mankind requires that they should declare the causes which impel them to the separation.
  • We hold these truths to be self-evident: that all men are created equal; that they are endowed by their Creator with certain unalienable rights; that among these are life, liberty, and the pursuit of happiness; that to secure these rights, governments are instituted among men, deriving their just powers from the consent of the governed; that whenever any form of government becomes destructive of these ends, it is the right of the people to alter or abolish it, and to institute new government, laying its foundation on such principles and organizing its powers in such form, as to them shall seem most likely to effect their safety and happiness.
  • —Thomas Jefferson, Declaration of Independence (1776)
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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.

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