5.1: The Logic of Arguments: Fundamentals

When you present a solution to a problem or answer a controversial question, persuasion is part of the assignment. There are different approaches to persuade members of your audience-you can appeal to their emotions, their ability to reason or even your own credibility on the topic being discussed. In the Air Force environment, your best approach to support your ideas and persuade others is by building a solid logical argument.

Though the word "argument" is commonly used to describe a quarrel or disagreement, it also has a positive meaning-it’s a series of statements intended to persuade others. In this chapter, when we use the term logical argument, we’re referring to a coherent set of statements that provide a position and support for that position based on information and facts, not just emotions.

This is important for two reasons. First, you build logical arguments every day: when you talk to your team about duties; when you talk to your boss about your workload and schedules; and when you sort out how best to accomplish the mission. If you build strong arguments, things are more likely to work out the way you think they should. Second, others are aiming arguments at you every day and many of these arguments fail logically. If you understand how arguments are constructed and where they go wrong, you’re less likely to buy into a failed logic.

Elements of a Logical Argument

Different textbooks have different terms and approaches to describe logical arguments. This chapter uses terminology found in The Craft of Research, by Booth, Comb and Williams. Logical arguments contain four elements:

• a claim
• evidence that supports the claim
• warrants linking pieces of evidence to the claim
• qualifications that limit the claim

First we’ll describe each of these terms and then we’ll illustrate them in a real-life example of an argument in the next section. The example will help clarify each point.

The Claim

Your claim is simply your position on an issue, your answer to a controversial question or your recommendation for resolving a problem. In academic writing, a claim is also called a thesis.

Evidence That Supports the Claim

By definition, every argument has evidence intended to give reasons for your claim. Another term for evidence is support ("support" and "evidence" are used interchangeably in this text). The similarity of these terms is clear in their definitions:

Evidence (a noun) is the data by which proof or probability may be based or may be admissible as testimony in a court of law.

Support, as a noun, is the information that substantiates a position; as a verb, support is the act to furnish evidence for a position.

If a piece of evidence is questionable, it may be attacked as a sub-claim. Then, you either have to provide additional evidence to prove the sub-claim is true, or eliminate it from your argument.

Warrants That Link Evidence to the Claim

With every piece of evidence, there are often assumptions, either stated or unstated, that link the evidence to the claim and explain why the evidence is relevant to the argument. These linking statements or concepts are called warrants. Warrants are important because they can be potential weaknesses in an argument.

Qualifications That Limit the Claim

Sometimes the argument will have qualifications - conditions that limit the claim. You can think of a qualification as a statement you attach to the claim with a big IF statement. We often notice these qualifications as we critically look at the evidence we have and realize its limitations.

Elements of a Logical Argument: An Example

Let’s use a real life example of a logical argument to show how the different elements work together. Suppose you’re responsible for selecting a guest speaker to teach topic \(\mathrm{XYZ}\) at a PME school. Ms. Jane Doe spoke last year and you’ve decided to invite her back. Your boss wants to know your recommendation and your rationale. Guess what? You’ve just been asked to produce a logical argument

CLAIM: We should invite Ms. Jane Doe to teach topic XYZ at this year’s class.

EVIDENCE, item #1: Ms. Doe has spent 26 years working with XYZ and is an expert in this field.

WARRANT, item #1: Spending 26 years of working with XYZ makes her an expert. (Another implied warrant is that we want an expert to teach topic XYZ.)

If someone wanted to attack this bit of evidence, he might ask you to prove the fact that she’s spent 26 years in the field-let’s see a resume!

If someone wanted to attack the underlying warrant, he may argue that she isn’t really an expert-maybe she’s been doing an entry-level job for 26 years.

But let’s suppose that Ms. Doe is indeed an expert in the field, and this is solid evidence.

EVIDENCE, item #2: Last year’s course directors all thought she did an excellent job.

WARRANT, item #2: These people know what they’re talking about.

If someone wanted to challenge this evidence, he might ask you to produce letters of recommendation. How enthusiastic are the directors about the job she did?

If someone wanted to attack the underlying warrant, he might question the course directors’ judgment. Maybe they were new to the job and didn’t know much about the topic. Maybe they were TDY during the presentation and were basing their recommendation on what they heard from others.

In this case, let’s assume that the course directors are both credible and enthusiastic. EVIDENCE, item #3: Ms. Doe is a very dynamic lecturer.

WARRANT, item #3: It’s good to have a dynamic lecturer.

Recall that evidence you provide to support your claim can be attacked as a sub-claim ... and this last bit of evidence looks vulnerable. How do we know that Ms. Doe is a dynamic lecturer? To back it up, you’d have to "support your support" on item #3 with something like this:

SUBCLAIM: Ms. Doe is a very dynamic lecturer.

SUBCLAIM EVIDENCE #1: Students provided five times the amount of feedback than is typical for a lecture.

SUBCLAIM WARRANT #1: Student interest is proportional to volume of feedback.

SUBCLAIM EVIDENCE #2: Ninety-two percent of feedback was very favorable and 8 percent was very unfavorable.

SUBCLAIM WARRANT #2: Polarized feedback implies a dynamic lecture.

Well, this additional information really does back up the fact that Ms. Doe is a dynamic lecturer, but it also indicates her views are controversial-8 percent of the student population really didn’t like her presentation. You may believe that your school’s goal is education and not to make every student happy, but you might qualify your claim with the following "IF" statement:

QUALIFICATION:

Ms. Jane Doe should be invited back to teach topic XYZ

IF

it is acceptable to have a controversial speaker at the school.