Approaches to Writing - Logical Evidence
Logical Explanations
Logical explanations are another type of support for your subpoints. Unlike evidence--facts, statistics, quotations, etc. located through research--logical explanations demonstrate your own careful reasoning.

The most common expression of logic is called a "syllogism." You may be familiar with this term from a logic course you have taken. (If not, you may want to familiarize yourself with this and some of the other fundamentals of logic by visiting the Web site, Argumentative Writing & Categorical Logic.)

A syllogism shows how a "major premise" and a "minor premise" result in a logical "conclusion"--that is, if both the major premise and minor premise are true.

For example, the following syllogism is logical:

Major Premise: All dogs are mortal.
Minor Premise: MaLaBu is a dog.
Conclusion: MaLaBu is mortal.

The following syllogism is NOT logical, because the major premise is not true:

Major Premise: All dogs are blind.
Minor Premise: MaLaBu is a dog.
Conclusion: MaLaBu is blind.

How can a syllogism serve as evidence in your argumentative paper? It can help explain the logic of one of your subpoints. It can offer "proof," just as evidence does, but proof that is more abstract than evidence.

For example, consider this subpoint (in blue) offered by a student in support of one of her main points (in brown). The evidence (in red) is quite convincing that physical harm awaits children who participate in violent gangs, but the claim that responsible parents do not care about their children's futures when they tolerate the threat of physical harm needs logical explanation (in green): By tolerating their children's involvement in violent gangs, parents signal to their children they no longer care about their children's future. Members of violent gangs often suffer physical injuries, long-term disabilities, or even death. These are possible calamities that no responsible parent would tolerate. According to sociologist Ruth Horowitz, who conducted a three-year study of Hispanic gangs in one Chicago community in the early 1970's, physical injuries among gang members are "relatively common." The physical injuries reported in her study were a result of gang members being hit by a baseball bat, fighting at school, and participating in drive-by shootings. Although most violent incidents among these gang members did not end in death, the community still experienced an average of five gang-related deaths per year. As Kristen Sandor O'Connor, author of "Gangs," warns parents, "If we don't educate ourselves and our kids, we may find ourselves . . . paying a deadly price." Since physical harm may affect a child for life, parents who would tolerate their children's involvement with violent gangs clearly show their disregard for their children's futures.

NOTE: A syllogism can easily be incorporated into your paragraph in sentence form (as above).

Any questions or comments for Kenn?

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