Rhetoric and Logic and Artificial Intelligence

Review: Logic vs. Rhetoric | Syllogism vs. Enthymeme

Below is the transcript of a decent overview of the difference between the syllogism and the enthymeme, and more broadly, logical reasoning vs. rhetorical persuasion–what we have been exploring in our initial discussions of rhetoric, documentary, and the Central Park Five. It was generated by Google’s new AI-search, Gemini.

We can extend the logic vs. rhetoric dynamic to AI. AI, built upon computational, mathematical, algorithmic logic, is thoroughly logical–updating of the syllogism. But the human use of any output generated by AI is a matter of rhetorical persuasion: information in need of interpretation, re-presenting.

Is there a place for AI and other artificial technologies in rhetorical invention? There has been from the beginning. One could argue that rhetoric itself is a technology that enables humans to artificially extend their powers of thinking into speech, memory, and composition. The “artistic” evidence or proof that is central to rhetorical persuasion, which refers to the shaping and composing of argument by human hands and minds, shares roots with artificial.

So, yes, you might find some AI-tools useful. But focus on them not for generating your own ideas or writing, but as tools for putting existing ideas and texts (which can and should be sourced) into conversation and composition with your emerging ideas and writing.

My AI guidelines, included in the syllabus under Academic Integrity:

Washington College has the following policy regarding academic integrity and plagiarism: Plagiarism is defined by the Honor Code as “willfully presenting the language, ideas, or thoughts of another person as one’s original work.”  Turning in the work of someone else (or something else in the use of an AI tool) and representing it as your own is plagiarism.  Relying on other texts, resources, and intelligence (both human and artificial) to generate our work is basic to what we do as scholars and writers. Acknowledging those resources is also basic to what we do. For that reason, quoting or paraphrasing or otherwise using the words or ideas of other people and resources (such as Wikipedia or ChatGPT)  without properly acknowledging your source is also a problem.  If you ever have any question at all about whether you are using a source correctly, ask me about it to learn more.  We will be talking and learning more about the rhetorical uses and potential abuses of artificial intelligence tools like ChatGPT (including two concerns you should keep in mind: AI can fabricate information and sources; the companies are not concerned with your data privacy). My guideline is that if you use any language (phrase, sentence, or longer) generated by an AI or other digital tool, it must be cited like any other reference to a text. Submitting a paper for this class that contains all or part of a paper that you submitted in another class, without the permission of both professors involved, is also a violation of the Honor Code. A student found guilty of plagiarism may fail the assignment or the course, and may be referred to the Honor Board for further adjudication.  Whenever you hand in a paper for this course, you will include as part of a preface an acknowledgement of the resources you have relied upon and a statement that your work has been completed in accordance with the Honor Code.

Integrity suggests wholeness; a synonym would be ecology. Your integrity affects the integrity of the whole learning environment here, in the class (where you are relying upon the response of your peers) and on campus. We will be talking further about the integrity of your writing and the ways that your writing can be inventive without being plagiarized. The point is that I take plagiarism seriously, but as such, also want you to learn and ask questions about it.

Logic vs. Rhetoric (transcript from Google’s Gemini):

What’s the difference between a syllogism and an enthymeme?

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Syllogisms and enthymemes are both forms of deductive reasoning, but they have some key differences:

Structure:

• Syllogism: A complete formal argument with three explicitly stated propositions:
  • Major premise: A general statement accepted as true.
  • Minor premise: A specific statement about something related to the major premise.
  • Conclusion: A logical deduction based on the two premises.
• Enthymeme: An incomplete syllogism where one or more parts (usually a premise) are left unstated. The audience is expected to fill in the missing information based on their shared knowledge or context.

Certainty:

• Syllogism: Aims for absolute certainty based on universally accepted truths. If the premises are true, the conclusion must necessarily be true.
• Enthymeme: Deals with probabilities and relies on shared beliefs or common knowledge. The conclusion is usually likely, not guaranteed.

Purpose:

• Syllogism: Used in logic and mathematics to demonstrate the validity of an argument.
• Enthymeme: Used in rhetoric and persuasion to convince or inspire an audience. Appeals to emotions and shared values alongside logic.

Examples:

• Syllogism: All humans are mortal (major premise). Socrates is a human (minor premise). Therefore, Socrates is mortal (conclusion).
• Enthymeme: He’s always been honest (unstated premise: honest people are trustworthy). You can trust him (conclusion).

In short:

• Syllogism: Formal, complete, seeks absolute certainty.
• Enthymeme: Informal, incomplete, uses probabilities and shared knowledge to persuade.

I hope this clarifies the differences!

https://gemini.google.com/share/e490446e0831

Invention, part 2: rhetorical techniques of argument and logical fallacies

Our further reading into the techniques and figures of argumentation moves us deeper into what the rhetor does during the process of invention, the discovering of all available means of persuasion in a given case. If the proof or evidence (logos) is scientifically certain (called “inartistic”), then it’s a matter for logic: the issue is irrefutable or indisputable, the information is not in need of interpretation. However, if the truth of the evidence is not certain, not irrefutable, but in fact arguable, then it’s a matter for rhetoric: it is information in need of interpretation, which means a plausible perspective must be developed, which means necessarily that it can be refuted. These are known as “artistic” proofs. We can begin to see why rhetoric applies so well to documentary film and writing, and also why rhetoric gave Plato the idealist such concerns. “Artistic” suggests that understanding of the truth is shaped (fabricated, made) by human hands and minds.

We have read about Stasis and can apply the 4 questions to Central Park Five as a key element of invention: for the prosecutor’s in the case, for Burns in re-presenting the case, and ultimately for us in analyzing Burns’ case (your first writing project).

We can also call upon the knowledge of Logical Fallacies. One of the ways to understand the rhetorical power–but at the same time, the rhetorical problem–of these techniques is to recognize that many of them can also be viewed as logical fallacies, depending on how they are used. We are decidedly in the messy, murky, and manipulative rhetorical realm of the human world when using and identifying these techniques, not in the pure, ideal realm of logic (Plato pointing up above). Argumentum ad Populum (arguing from popular opinion) is both a figure of address and an informal logical fallacy.

In other words, these rhetorical techniques of argumentation are tools for developing an enthymeme, not for the logical syllogism. In fact, we might think of a logical fallacy as a rhetorical technique that in some way is disguising itself as a logical syllogism. To be more specific: there are two types of fallacies or invalid ways of arguing. Formal fallacies, in which the logic rules of the syllogism are violated (the realm of philosophy and scientific evidence). And there are informal fallacies, the realm of rhetoric, where the problem is not with validity as much as relevance. A number of fallacies known by various names could be grouped under this mistake in reasoning: making sweeping generalization, or making a general conclusion about a more specific example or class without qualification. For example: false cause, or anecdotal, or the genetic fallacy.  The Fallacy Files provides a related example known as secundum quid, when qualifications are ignored:

Form:

Xs are normally Ys.
A is an X. (Where A is abnormal.)
Therefore, A is a Y.

Example:

Birds normally can fly.
Tweety the Penguin is a bird.
Therefore, Tweety can fly.

Or there is the fallacy of false causation known by the Latin phrase Post hoc ergo propter hoc (Latin: “after this, therefore because of this”), an informal fallacy that states: “Since event Y followed event X, event Y must have been caused by event X.” It is often shortened simply to post hoc fallacy. Do we see secundum quid or the post hoc fallacy at work in the Central Park Five case?

These fallacies operate through a break-down in reasoning (logos)–that’s why they are known as logical fallacies. But as informal fallacies, we are really talking about rhetoric more than logic. We are in the world of probability and plausible and qualified perspectives (Some Xs are Ys, in certain cases), not in the pure world of logic and universal certainty (All Xs are Ys). Identifying it as a fallacy doesn’t prevent its use, since the use of the fallacy can be–as I think we see in the case of the Central Park Five–rhetorically effective and powerful.  However, a better grasp of the rhetorical problem of generalization gives us greater power for our rhetorical analysis. We can better see and critique what is going on. We can call foul, argue that it is a generalization that does not offer proper qualification.

Burns demonstrates that such rhetorical knowledge does not always win out in the rough world of politics and the tabloid press, where narratives based on preconceptions are quickly formed and then hard to revise. In this way, the police/prosecution/press are not guilty of injustice, in the scientific or legal or formal, logical senses of invalid argument. They use rhetorical tools of persuasion and narrative and invention that are available to them. The fallacy of their argument is informal, rhetorical: it is a problem of relevance. 

Burns shows us that this rhetorical knowledge also matters in the world of documentary. In countering the rhetoric used by the police and media, she re-presents an argument that she contends is more relevant to the case and its complexities. Are you persuaded by the fallacies she illuminates? In what way does the film and its available means of representation (image, sound, voice, etc.) aid Burns in this illumination? Which scenes or moments stand out?

Further Reading:

For a decent review of the syllogism vs. the enthymeme–and our larger discussion of logic vs. rhetoric, check out this AI-generated Google response. It’s also a good time, as we head toward the first writing project, to read through my guidelines and expectations for properly attributing AI tools if you use them as a resource or a source (in the syllabus under Academic Integrity).

You can further explore the world of logical fallacies at the Taxonomy of Logical Fallacies.

A more reader friendly listing of numerous informal fallacies can be found at My Logical Fallacies. What other fallacies do you see at work in the argumentation supporting the case against the Central Park Five. Is Burns guilty of any fallacies of her own, particularly in her refutation of the case? For example, in her refutation of the police, does she simply turn the accusations against the accusers, known as Tu Quoque, a form of argumentum ad hominem?

Since rhetoric combines reasoning with language and words, one very basic and important method of rhetorical analysis is always to think about the roots of the words we use. In other words, etymology–with a resource like the OED or the Etymology Online [both linked under our Resources on the right side of Available Means]. For example:

fallacy (n.)

late 15c., “deception, false statement,” from Latin fallacia “deception, deceit, trick, artifice,” abstract noun from fallax (genitive fallacis) “deceptive,” from fallere “deceive” (see fail (v.)). Specific sense in logic, “false syllogism, invalid argumentation,” dates from 1550s. An earlier form was fallace (c. 1300), from Old French fallace.

argument (n.)

early 14c., “statements and reasoning in support of a proposition or causing belief in a doubtful matter,” from Old French arguement “reasoning, opinion; accusation, charge” (13c.), from Latin argumentum “a logical argument; evidence, ground, support, proof,” from arguere “make clear, make known, prove” (see argue). Sense passed through “subject of contention” (1590s) to “a quarrel” (by 1911), a sense formerly attached to argumentation.

We could also think of a fallacy as a problem when reasoning becomes unbalanced, out of whack. Analogy is a figure of reasoning by comparison and proportion. It emerges from mathematical logic and Plato, but makes its way to rhetoric.

analogy (n.)

early 15c., “correspondence, proportion,” from Old French analogie or directly from Latin analogia, from Greek analogia “proportion,” from ana “upon, according to” (see ana-) + logos “ratio,” also “word, speech, reckoning” (from PIE root *leg- (1) “to collect, gather,” with derivatives meaning “to speak, to ‘pick out words'”).

A Greek mathematical term given a wider sense by Plato. The meaning “partial agreement, likeness or proportion between things” is from 1540s. In logic, “an argument from the similarity of things in some ways inferring their similarity in others,” c. 1600.

also from early 15c.

The Rhetoric of Invention: plausible perspectives

Logic (or dialectics, philosophy) is the fist, rhetoric is the open hand. Both are ways of pursuing arguments. What’s the difference?  Leith says the difference is a matter of persuasion (rhetoric’s version of logos, likely and probable evidence or proof) as opposed to the kind of “proof absolute” associated with formal logic used in math and science, and valued by philosophical logic (60). Leith points to the importance of Aristotle in establishing this understanding of rhetoric’s emphasis on persuasion as opposed to certainty.

In part 2 of his Rhetoric, Aristotle identifies three modes of persuasion, known to us still by the Greek words ethos, pathos, and logos.  Here is Aristotle:

Of the modes of persuasion furnished by the spoken word there are three kinds. The first kind depends on the personal character of the speaker; the second on putting the audience into a certain frame of mind; the third on the proof, or apparent proof, provided by the words of the speech itself. Persuasion is achieved by the speaker’s personal character when the speech is so spoken as to make us think him credible. We believe good men more fully and more readily than others: this is true generally whatever the question is, and absolutely true where exact certainty is impossible and opinions are divided. This kind of persuasion, like the others, should be achieved by what the speaker says, not by what people think of his character before he begins to speak. It is not true, as some writers assume in their treatises on rhetoric, that the personal goodness revealed by the speaker contributes nothing to his power of persuasion; on the contrary, his character may almost be called the most effective means of persuasion he possesses. Secondly, persuasion may come through the hearers, when the speech stirs their emotions. Our judgements when we are pleased and friendly are not the same as when we are pained and hostile. It is towards producing these effects, as we maintain, that present-day writers on rhetoric direct the whole of their efforts. This subject shall be treated in detail when we come to speak of the emotions. Thirdly, persuasion is effected through the speech itself when we have proved a truth or an apparent truth by means of the persuasive arguments suitable to the case in question.

There are, then, these three means of effecting persuasion. The man who is to be in command of them must, it is clear, be able (1) to reason logically, (2) to understand human character and goodness in their various forms, and (3) to understand the emotions-that is, to name them and describe them, to know their causes and the way in which they are excited. It thus appears that rhetoric is an offshoot of dialectic and also of ethical studies. Ethical studies may fairly be called political; and for this reason rhetoric masquerades as political science, and the professors of it as political experts-sometimes from want of education, sometimes from ostentation, sometimes owing to other human failings. As a matter of fact, it is a branch of dialectic and similar to it, as we said at the outset. Neither rhetoric nor dialectic is the scientific study of any one separate subject: both are faculties for providing arguments. This is perhaps a sufficient account of their scope and of how they are related to each other.

Leith reminds us that many of the categories and divisions rhetoric has us think about are “fuzzy art” since they “overlap and interpenetrate” (43). That applies certainly to these three appeals: structures for thinking about 3 core elements necessary for a persuasive composition, different but related: ethos can blend with pathos and also relate to logos. But it also helps to get a better grasp of each of these aspects.

Aristotle goes further in focusing on logos (and its somewhat fuzzy relation to, and difference from mathematical or philosophical logic, also called dialectics) by distinguishing artistic and inartistic evidence or proof. The kind of evidence used in rhetorical persuasion is most often artistic–crafted by hand.  Inartistic evidence is given and certain. Think of a mathematical proof or scientific formula. This is where the difference between the “syllogism” and the “enthymeme” comes forward.

Syllogism vs. Enthymeme:

As Leith explains in his discussion of “Invention,” Aristotle’s rhetorical “logos” means evidence that the rhetorician presents for proof, but proof which is plausible, not absolute or certain. In the context of judicial rhetoric, as Leith explains, we still identify this rhetorical proof with the phrase “reasonable doubt.” Aristotle’s logos is related to, but different than (a wayward cousin Leith calls it) the philosophical logic of Plato. This difference between rhetoric and logic can be understood further in the difference between the syllogism and the enthymeme (two of our keywords). In Part 1 of his treatise on Rhetoric, Aristotle describes syllogism as the primary technique of philosophical logic or “dialectic,” while the enthymeme is a primary technique of rhetoric. The key difference we see concerns truth viewed as a certainty vs. truth viewed as a probability, what is “approximately true.”

And further on in Part 2, he defines the enthymeme as a “rhetorical syllogism,” by this asserting that it is an argument that has logic, but deals with probabilities and contingencies, and can be refuted–whereas the pure logic of the syllogism is irrefutable and absolute. The logic of the syllogism or philosophical dialectic (the kind that Plato valued exclusively) leads to truth that is already established. The evidence of the rhetorical syllogism, however, in dealing with the human world of actions and behavior, leads the audience to a decision that is persuasive, but has “alternative possibilities.” The premise is assumed (or half-assed, as Leith puts it), not certain or established, not axiomatic (irrefutable). Think of the way Nichols describes the truth of documentary film: a framework for a plausible perspective; information in need of interpretation. Dialectic and logic, at least as Plato conceived it (the fist), deals with information; rhetoric, as Aristotle conceived it is the open hand, shaping and framing the information because it is in need of interpretation.

Syllogism (scientific/mathematical/philosophical logic)

All X = Y

Z also = X

Therefore Z must = Y

Enthymeme or Thesis or more simply Argument

[Some X = Y]

Z = X

Therefore Z most likely or probably = Y

The etymology of the word “enthymeme” suggests that it entails the reasoning or argumentation that is necessary in an imperfect , shadowy world of dust and smoke, rather than the perfect world of pure logic.

“a syllogism in which one premise is omitted,” in Aristotle, “an inference from likelihoods and signs,” 1580s, from Latin enthymema, from Greek enthymema “thought, argument, piece of reasoning,” from enthymesthai “to think, consider,” literally “to keep in mind, take to heart,” from en “in” (see en- (2)) + thymos “spirit, courage, anger, sense” (from PIE root *dheu- (1) “dust, vapor, smoke”)

Here is a useful, further discussion of the sort of mathematical/axiomatic/scientific logic of the syllogism that Aristotle develops in his other work–in contrast with the rhetorical syllogism he discusses in Rhetoric, where the concern is not validity but relevance and probability. From a recent essay, “How Aristotle Created the Computer”:

Aristotle’s central observation was that arguments were valid or not based on their logical structure, independent of the non-logical words involved. The most famous argument schema he discussed is known as the syllogism:

• All men are mortal.
• Socrates is a man.
• Therefore, Socrates is mortal.

You can replace “Socrates” with any other object, and “mortal” with any other predicate, and the argument remains valid. The validity of the argument is determined solely by the logical structure. The logical words — “all,” “is,” are,” and “therefore” — are doing all the work.

Aristotle also defined a set of basic axioms from which he derived the rest of his logical system:

• An object is what it is (Law of Identity)
• No statement can be both true and false (Law of Non-contradiction)
• Every statement is either true or false (Law of the Excluded Middle)

These axioms weren’t meant to describe how people actually think (that would be the realm of psychology), but how an idealized, perfectly rational person ought to think.

Aristotle’s axiomatic method influenced an even more famous book, Euclid’s Elements, which is estimated to be second only to the Bible in the number of editions printed.

Why then do we need rhetoric? Because humans aren’t computers, aren’t perfectly rational; the world isn’t ideal.

When researching (or discovering, inventing) an argument for rhetorical persuasion (not philosophical logic), Aristotle identifies various “topics” or commonplaces that can serve as a model. You read more about these in the “Judicial Rhetoric” chapter in Leith, and will return to this as we go further into Central Park Five and the case.  Here is a useful listing of all the topics provided by Silva Rhetoricae.

With Aristotle and the rhetorical concept of invention in mind, what can we say–from our emerging rhetorical perspective–about the proof that the police/prosecutors/media produce in the case, and the means that are available to them to produce the truth of their case? What can we say about the proof that Sarah Burns uses and represents in her response? What means are available to her?

Further Reading Resource:

• A chart detailing the various components of Invention outlined in Aristotle’s Rhetoric.
• A great summary of Aristotle’s Rhetoric from the Stanford Encyclopedia of Philosophy.
• Topics of Invention (Silva Rhetoricae).

rhetorical concepts discussed: ethos, pathos, logos; enthymeme vs. syllogism; plausibility; rhetoric vs. dialectic/logic; topics/commonplaces

image credit: “How Aristotle Created the Computer” (The Atlantic, 2017)