Arguments require proofs, and according to Aristotle, there are both artistic or internal and inartistic or external kinds of proofs.

Inartistic proofs are those that exist independently of the act or artifact under consideration—they may well effect the persuasiveness of the text, but the rhetor doesn’tinvent or create them. The rhetor collects them and puts them to use. Some inartistic proofs include:

• Expert witness testimony
• Citations from authorities
• Interviews, contracts, or other documents
• Physical evidence (say, DNA or fingerprints from a crime scene)
• Statistics
• Opinion surveys
• Other generally accepted facts

Inartistic proofs offer powerful support in an argument, but they don’t prove much at all by themselves. The rhetor has to build an argument around them–that means that inartistic proofs typically need to be situated by artistic proofs.

In the sensationalized trial of OJ Simpson in 1995, for example, the prosecution presented the indisuptable physical evidence of the bloody gloves worn by the killer in the murder of Nicole Brown Siimpson and Ron Goldman. But this incriminating evidence against OJ ended up getting him acquitted when the prosecution asked him during the trial to put on the gloves and he could not get his hands into them. Defense attorney Johnnie Cochran created a successful counter-argument around that fiasco, famously uttering the words: “If it doesn’t fit, you must aquit.” An enthymeme turns the physical evidence into a successful argument:

• Major Premise (unstated): The gloves worn by the killer must fit the killer’s hands
• Minor Premise: The gloves worn by the killer do not fit OJ’s hands
• Conclusion: (Therefore) OJ was not the killer

The inartistic proof (physical evidence) is situated here via the artistic proof: logos.

Artistic proofs fall into 3 categories, according to Aristotle: logos, ethos, and pathos.

LOGOS: the logical proofs the rhetor offers, the proofs that appeal to the audience’s sense of reason. Here are some types of logical reasoning used by rhetoricians:

• Inductive reasoning: begins with a series of specific instances that add up to a generalized conclusion. Example: I sampled six different apples from this tree, and they were all sour. Conclusion: this tree’s apples are sour. Or: There were ten car accidents in Austin last week in which people were seriously injured. In eight of those cases, the driver was chatting on a cell phone. Conclusion: you are more likely to have a serious wreck if you talk on a cellphone while driving.
• Deductive reasoning: begins with a generalization (major premise) that the audience will likely agree to, and then applies the generalization to a specific case (minor premise) and draws a conclusion about that minor premise. So:

1. Major premise: It’s unjust for two people who do the same job to not make the same pay. Minor premise: Jane is doing the same job as Jack and earning only 2/3 the pay. Conclusion: That is unjust.
2. Major premise: All true champagne is made in the Champagne area of France. Minor premise: Laurent-Perrier is a true champagne. Conclusion: Therefore it must be made in France.

I could also put that enthymatically, leaving out the major premise or the conclusion (or both) b/c I think you’ll all be able to fill it in: “Jane is doing the same job as Jack and only making 2/3 the pay!” (You can do the rest…you fill in the blanks.)

• rhetorical examples. Citing an instance of what you’re talking about—“let me tell you about Mr. Smith, who worked hard in a machine shop for 25 years and then got lung cancer. Because he didn’t have insurance, he couldn’t get treatment.” A rhetor could also rely on familiar fictional examples, like Aesop’s fables or a scene from a novel or film, or a rhetor could cite historical or hypothetical examples. These examples may or may not add up to induction (it may take several examples to proceed inductively); but the key is that they ought to operate synecdochally: as synecdoche, part for whole. Mr. Smith could be any of us.
• Analogy. Placing one example beside another for comparison, as when proponents of legalizing marijuana say its prohibition is analogous to the prohibition of alcohol, which also didn’t work.
• Argument by contrast: placing one example beside another for contrast, as when proponents for invading Iraq argued that it was nothing like Vietnam.

A rhetorician (rhetorical critic–that’s you!) attempts to discern the logical moves in an argument, particularly what it is that the rhetor assumes you already believe (the presumed commonplace).

ETHOS. The effect that the speaker’s credibility or character has on the audience. According to Aristotle, to be credible, rhetors must seem to show intelligence, fair-mindedness, and good will toward the audience to be successful. There are two kinds of ethical appeal:

1. Situated ethos is the inartistic kind, the ethos a speaker walks in with. It involves one’s reputation, one’s credentials (M.D., Ph.D., ex-con, etc.), one’s basic appearance, known associations, etc.
2. Invented ethos is created by the speaker during the speech. What you decide to wear is already part of your invented ethos, as is your tone and style of delivery.

To display intelligence, a rhetor must do her homework and be well informed; to display fair-mindedness, he must present his case in a balanced way; and to display good will toward the audience, she must articulate the necessary information for an audience to make a good decision. Just for example:

• Dealing fairly with one’s opposition can be an indication of how fair-minded he or she is, and probably of how trustworthy.
• Citing the relevant sources correctly and fairly demonstrates that you’ve done your homework, that you’re trustworthy and intelligent.
• Speaking clearly and articulately also demonstrates intelligence and confidence. On the other hand, if you try too hard to sound intelligent by using big words or jargon or copping a ‘tude, you’re likely not to come off well. If you speak to a casual crowd at Joe’s Bar and Grill in the queen’s English, you’re likely to come off as out of touch or pretentious.
• Dressing appropriately demonstrates a sense of respect and responsibility. If you go for a corporate job interview wearing flipflops and a nose ring, it’s possible that you’re creating the wrong ethos for the occasion. If you went to a job interview at a tattoo parlor wearing your best business suit, you’d probably also be creating the wrong ethos for the occasion.
• How a rhetor presents him or herself (with confidence, arrogance, nervousness, etc.) is an element of his or her character creation. And it will affect in some small or big way that rhetor’s credibility with the audience at hand.

The critic must discern how the rhetor’s character, both as known to the audience prior to the rhetorical act or artifact and as presented to the audience during the act or artifact, facilitates the acceptance of belief on the part of the audience.

PATHOS. Appeals designed to generate emotions and a sense of identification in the audience by stirring their sympathies and imagination. Pathos therefore refers to both the emotional and imaginative impact of the message on the audience. Emotions the rhetor might want to stir include a sense of pity, fear, shame, anger, joy, shared pride, etc. There are a handful of ways to move the audience emotionally; two significant ones:

• Vivid description, a bringing before the eyes or actualization, a way of speaking or writing that makes the lifeless living through metaphor. Giving the listener or reader a sense that s/he is there, experiencing what is being described, is one of the most powerful types of pathetic appeal. Moving personal narratives that turn an abstraction into something palpable and present are particularly powerful. Using actual images can do this, as well.
• Emotionally charged language and delivery—showing signs yourself of the very emotion you hope to arouse in your audience.

Pathetic appeals are typically described as a two-step process: first, the speaker presents causes for the emotion (“pathemata,” or singular: “pathema”) to arouse, intensify, or change the audience’s emotion. Then that emotion functions in the audience as a reason for embracing an idea or taking action.