Learning Objectives

  • Recognize appeals to logos
  • Use the STAR method to evaluate appeals to logos

Appeals to Logos

Logos is about appealing to your audience’s logical side. You have to think about what makes sense to your audience and use that as you build your argument. As writers, we appeal to logos by presenting a line of reasoning in our arguments that is logical and clear. We use evidence, such as statistics and factual information, when we appeal to logos.

In order to develop strong appeals to logos, we have to avoid faulty logic. Faulty logic can be anything from assuming one event caused another to making blanket statements based on little evidence.

Appeals to logos are an important part of academic writing, but you will see them in commercials, as well. Although they more commonly use pathos and ethos, advertisers will sometimes use logos to sell products. For example, commercials based on saving consumers money, such as car commercials that focus on miles per gallon, are appealing to the consumers’ sense of logos.

As you work to build logos in your arguments, keep the following strategies in mind:

  • Both experience and source material can provide you with evidence to appeal to logos. While outside sources will provide you with excellent evidence in an argumentative essay, in some situations, you can share personal experiences and observations. Just make sure they are appropriate to the situation and you present them in a clear and logical manner.
  • Remember to think about your audience as you appeal to logos. Just because something makes sense in your mind, doesn’t mean it will make the same kind of sense to your audience. You need to try to see things from your audience’s perspective. Having others read your writing, especially those who might disagree with your position, is helpful.
  • Be sure to maintain clear lines of reasoning throughout your argument. One error in logic can negatively impact your entire position. When you present faulty logic, you lose credibility.
  • When presenting an argument based on logos, it is important to avoid emotional overtones and maintain an even tone of voice. Remember, it’s not just a matter of the type of evidence you are presenting; how you present this evidence is important as well.


Watch the video below and think about how it appeals to logos.

You can view the transcript for “2009 Toyota Prius Hybrid Cars- Safety Review” here (opens in new window).

Evaluating Logos

Logos may seem like the most straightforward of the logical appeals, but recognizing such appeals is trickier than you might expect. Especially in the age of “alternative facts,” it is important that you be able to recognize valid logical and/or factual evidence. The STAR criteriaSufficiency, Typicality, Accuracy, and Relevance—are a handy means of evaluating content and deciding whether or not it is logically valid.

Measure  Question  Examples and Notes


Is there enough cited evidence to support the conclusion?

Generally, only “strongly” and not “weakly” supported conclusions should be accepted. The more controversial a claim is, the more evidence authors should provide before expecting an audience to accept it. If the evidence is not sufficient, the author may need to modify or qualify the claim, by stating that something is true ‘sometimes’ rather than ‘always’.


Is the cited evidence typical or representative?

If an author makes a claim about a whole group but the evidence is based on a small or biased sample of that group, the evidence is not “typical.” Similar problems stem from relying just on personal experiences (anecdotal evidence) and from “cherry picking” data by citing only the parts that support a conclusion while ignoring parts that might challenge it.


Is the cited evidence up to date and accurate?

Authors using polls, studies and statistics must ask whether the data were produced in a biased way and also ask whether the sample was large and representative of its target population so that results were outside the “margin of error.” (Margin of error: If a sample is too small or not well chosen, results may be meaningless because they may represent random variation.)


Is the cited evidence directly relevant to the claim(s) it is being used to support?

An author may supply lots of evidence, but the evidence may support something different from what the person is actually claiming. If the evidence is not relevant to the claim, the author may need to modify or qualify the claim—or even to acknowledge that the claim is indefensible.

Manipulative Appeals to Logos

Diagramming an argument can help you determine if an appeal to logos is manipulative. Are the premises true? Does the conclusion follow logically from the premises? Is there sufficient, typical, accurate, and relevant evidence to support inductive reasoning? Is the speaker or author attempting to divert your attention from the real issues? These are some of the elements you might consider while evaluating an argument for the use of logos.

Pay particular attention to numbers, statistics, findings, and quotes used to support an argument. Be critical of the source and do your own investigation of the “facts.” Maybe you’ve heard or read that half of all marriages in America will end in divorce. It is so often discussed that we assume it must be true. Careful research will show that the original marriage study was flawed, and divorce rates in America have steadily declined since 1985 (Peck, 1993). If there is no scientific evidence, why do we continue to believe it? Part of the reason might be that it supports our idea of the dissolution of the American family.

Try It

Study the mapped visualization of crime in the U.S. below and answer the questions about how it appeals to logos.

map of US showing number of crimes per state

The misrepresentation of information or data is often accompanied by logical fallacies. We’ll examine these in more detail later, but they generally jump to conclusions, make generalizations, or frame the argument in a way that manipulates the logic of an argument.

Logos and Kairos

Kairos is the fourth rhetorical appeal, but it is almost always best explained in context with the other rhetorical appeals. The word comes from the ancient Greek καιρός (kairós), and means when time or conditions are right for the accomplishment of a crucial action; the opportune and decisive moment.

In his article “Critical-Rhetorical Ethnography: Rethinking the Place and Process of Rhetoric,” Aaron Hess provides a definition of kairos for the present day that bridges the two classical applications. Hess addresses Poulakos’s view that, “In short, kairos dictates that what is said must be said at the right time.” He suggests that kairos also considers appropriateness. According to Hess, kairos can either be understood as “the decorum or propriety of any given moment and speech act, implying a reliance on the given or known” or as “the opportune, spontaneous, or timely.”

Kairos is an important part of appeals to logos because all logical information is contextual. In other words, you can not use data from a 1960s study about cancer treatment without contextualizing it: it is no longer timely in 2017.

The appropriateness of information is also related to kairos. Even if information is logical and factually correct, it may not always be timely to present it. You must evaluate the rhetorical situation in order to balance the appeals appropriately, and an important part of the rhetorical situation is the time.


kairos: a time when conditions are right for the accomplishment of a crucial action; the opportune and decisive moment.

logical fallacy: a flaw in reasoning or a flawed structure that undermines the validity of an argument

logos: appeal to logic



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