Logos is a rhetorical device that uses logic, reasoning, and factual evidence to support an argument or persuade an audience.
Logos refers to one of the three main technical means of persuasion in rhetoric. According to Aristotle, it is the means that has to do with the arguments themselves.
Aristotle claims that there are three technical means of persuasion:
“Now the proofs furnished by the speech are of three kinds. The first depends upon the moral character of the speaker, the second upon putting the hearer into a certain frame of mind, the third upon the speech itself, in so far as it proves or seems to prove” (Aristotle, Rhetoric, ca. 367-322 B.C.E./1926, Book 1, Chapter 2, Section 3).
Each of these corresponds to the three means of persuasion:
- Ethos (Appeal to credibility): Persuasion through establishing the character of the speaker.
- Pathos (Appeal to emotion): Persuasion through putting the hearer into a certain frame of mind.
- Logos (Appeal to logic): Persuasion through proof or seeming proof.
For Aristotle, speech consists of three things: the speaker, the hearer, and the speech. These correspond to ethos, pathos, and logos, respectively. The latter is the subject of this article.
Definition of Logos
At its core, logos refers to the use of logic (or perceived logic) to persuade.
However, logos may be the most confusing of the three means of persuasion because the word has been used by different philosophers to mean different but related things.
- Heraclitus of Ephesus used the word logos to refer to something like the message that the world gives us (Graham, 2021).
- The sophists used the term to refer to discourse in general.
- Pyrrhonist skeptics used the term to refer to dogmatic accounts of debatable matters.
- The Stoics meant by it the generative principle of the universe.
I could list further examples, but for this article, Aristotle’s definition will suffice.
Logos, in rhetoric, refers to persuasion through logical argumentation or its simulation (Keith & Lundberg, 2017).
As Aristotle writes,
“… persuasion is produced by the speech itself, when we establish the true or apparently true from the means of persuasion applicable to each individual subject.” (Aristotle, Rhetoric, ca. 367-322 B.C.E./1926, Book 1, Chapter 2, Section 6).
Syllogisms, enthymemes, examples, and other arguments use logos to influence people’s thinking. Due to the structure of this persuasion tool, it is the only one that can directly argue for the speaker’s point of view. What Aristotle stresses over and over again is that deceptive or fallacious arguments can have a persuasive effect if the fallacy is concealed well enough.
Persuasion through logos requires only that the hearers think that something has been proven, whether it actually has been is a different matter.
Logos Examples
- Scientific Research: Any form of scientific research is fundamentally grounded in logos, as it relies on empirical data, statistical analysis, and logical reasoning to draw conclusions. For example, if you were to present the scientific evidence to a consumer about why your product is the best, it may convince them to switch brand loyalty over to you.
- Legal Arguments: In court, attorneys use logos extensively when presenting evidence, citing precedents, or constructing logical arguments to persuade the judge or jury. Generally, it is expected that the jury be presented the best objective evidence in order for them to make an objective decision. However, at times, they will rely on pathos, and the judge’s job is often to curtail this if needed.
- Newspaper Editorials: Newspaper editorials often use logos to make a persuasive point, presenting facts, statistics, and logical analysis to support the writer’s viewpoint. Without facts and data, the readers my close the newspaper and dismiss the writer as simply engaging in hearsay.
- Referencing in Essays: In essays, we are often required to cite our sources. This is, in part, relying on ethos (appeal to credibility), but at the same time, it’s also allowing the reader to go ahead and check the primary data to ensure it’s correct.
- Financial Reports: Financial analysts use logos when they analyze data, financial statements, and market trends to provide investment advice. They know an investor wants to make the most evidence-based decision as possible with the data, so they need to present this evidence as clearly as possible.
- Medical Diagnosis: Doctors use logos when they diagnose patients by interpreting symptoms, medical histories, and test results to arrive at a logical conclusion. Without evidence, customers may distrust the doctor and refuse to follow the doctor’s advice.
- Speeches and Presentations: Speakers and debaters often use logos in their speeches or presentations to make their points more persuasive, providing evidence, statistics, and logical analysis to back up their arguments, with the intent of convincing the audience and winning the debate over the competitors (although, pathos is highly convincing in speeches as well).
- Instruction Manuals: Logos is used in instruction manuals for constructing furniture where a logical sequence of steps is provided to guide users in assembling a product or operating a piece of software. An instruction manual won’t say “if you feel like it,…” because this won’t get the job done – constructing the item!
- Funding Proposals: In making a funding pitch, proposals are often supported by logos in the form of cost-benefit analyses, case studies, and logical reasoning to convince others that their money will be in good hands.
- Problem-Solving: In a group’s blue skies brainstorming session or a problem-solving meeting, logos is used when the participants identify the problem, analyze the factors contributing to the problem, and propose logical solutions based on evidence and reasoning.
- Technological Innovations: When developing a new product or technology, engineers and designers use logos to analyze the needs of the market, create a logical design to meet those needs, and justify their decisions with reasoning and evidence. In fact, engineers need strong analytical skills and have to rely extensively on logos (rather than pathos or ethos) in their daily job roles.
Logos as Perceived Logic
Aristotle writes that even fallacious arguments are examples of logos, because they seem to prove something. In other words, logos isn’t just being logical, rather it’s attempting to appear logical.
Here are some examples:
- Straw Man Fallacy: This happens when an individual distorts, exaggerates, or misrepresents someone’s argument in order to make it easier to attack. For example, “My opponent believes in healthcare reform, he must want to give free healthcare to everyone.” Here, they are attempting to construct some logic that isn’t really there – they’re actually creating false facts to put forward a point of view!
- Slippery Slope Fallacy: This is an argument that suggests taking a minor action will lead to major and often ludicrous consequences. For example, “If we allow students to redo tests, they’ll want to redo homework, quizzes, and even final exams!” Here, the argument sounds like it could be logical, but draws a long bow and makes claims that something will happen, even though it may not (and probably won’t) actually come to pass.
- False Dichotomy Fallacy: This fallacy occurs when an argument presents only two options or sides when there may be more. For example, “You’re either with us, or against us.” Once the false dichotomy is constructed, logos can be used to convince people one perspective is better than the other, as if only the two exist.
- Hasty Generalization Fallacy: This happens when someone makes a broad conclusion based on a small or unrepresentative sample size. For example, “I met a rude person from City X, therefore everyone from City X must be rude.” Here, they are attempting to use logic – and their argument is ostensibly logical – but in reality, it (like the slippery slope) draws a long bow and is unlikely to actually be true.
Logos Strengths
- Appeal to rationality: For many people, the apparent rationality of a speech is its most important and persuasive part. Especially in academic settings where the orator cannot make themselves stand out through appeals to ethos and pathos, logos is often the most important part of the rhetorical triangle.
- Trustworthiness: While pathos and ethos are often viewed with suspicion, there is no such negative stigma attached to logos. Appeals to emotion or personal authority may seem dishonest and manipulative, but arguments, unless fallacious, rarely seem so.
- Counter arguments: Logos is the only mode of persuasion that can directly address objections because the evaluation of opposing views is itself a rational activity.
Logos Weaknesses
- Subjective matters: In certain settings, logos can be far less persuasive than pathos and ethos. This is particularly evident in settings where there are no objective criteria for deciding if the speaker is right or wrong.
Conclusion
Logos refers to one of the three main technical means of persuasion in rhetoric. According to Aristotle, it is the means that has to do with the arguments themselves.
See Also: The 5 Types of Rhetorical Situations
References
Aristotle. (1926). Rhetoric. In Aristotle in 23 Volumes, Vol. 22, translated by J. H. Freese. Harvard University Press. (Original work published ca. 367-322 B.C.E.)
Hansen, H. (2020). Fallacies. In E. N. Zalta (Ed.), The Stanford Encyclopedia of Philosophy (Summer 2020). Metaphysics Research Lab, Stanford University. https://plato.stanford.edu/archives/sum2020/entries/fallacies/
Rapp, C. (2022). Aristotle’s Rhetoric. In E. N. Zalta (Ed.), The Stanford Encyclopedia of Philosophy (Spring 2022). Metaphysics Research Lab, Stanford University. https://plato.stanford.edu/archives/spr2022/entries/aristotle-rhetoric/