1. Categorical (RBJ 193) -- X is a Y, where presenter and audience agree on what Y is
2. Definition (207) -- X is a Y, where there isn't necessarily any agreement on what Y is; presenter must jump that hurdle before being able to make the definition argument. And some concepts defy definition (e.g. Y = love, truth, free will).
3. Cause and effect -- Event X -> result Y; numerous possibilities can be mistaken for this. See the separate page on this subject for details.
4. Resemblance/similarity (262) -- X is like (or, ~) Y. This argument is seen in:
   • products: brand 1 ~ brand 2; generic ~ brand
   • societal behavior: this generation ~ previous
   • memory: "deja vu all over again"
   • current events: situation ~ precedent
5. Evaluation (281) -- X is good (or bad). The evaluation is made by the audience, or a subset (or even a single member) of the audience. This means that though aspects of the presentation are weighed (including facts), the decision may still come down to a consensus, or a vote, or even the opinion of one person "in charge."
6. Proposal (308) -- Do X! (or, We should do X) This argument is most likely to succeed when the warrant (as usual, shared) includes positive outcomes/benefits. We see this argument in commercials, votes/polls, and courting :-) :-) :-).

Rhetoric is the art of making some sort of claim and defending it with evidence. The need for a defense suggests that the audience won't "buy in" without it.

So I tell students their claims must be

1. controversial, in the sense that there's no guarantee the audience or the research materials will completely support it;
2. about an engineering-related topic, in the sense that the evidence can be judged through some combination of analysis, demonstration, inspection, similarity, and/or testing.

Here's the full list of difficulties I've seen with student (and workplace) proposals:

1. Claim is too broad. (Example: "genetic engineering is/isn't improving our quality of life.") Our lives aren't long enough for us to prove this to more than a handful of people.
2. Claim is intuitively indefensible. (Example: "the Mars Climate Orbiter was lost because of one error committed by one person.")
3. Claim involved excessive dependence on pathos, that is, it's an emotional plea. (Example: "cloning is wrong.")

If a claim absolutely depends on the audience buying into an emotion-based warrant, they might as well give up now. Many students have trouble with this, because they're used to dealing in first-semester Rhetoric with "the great issues of the day" (e.g. abortion, gun control, death penalty, etc.) and see emotion-based argument all the time.

The engineer in practice can't get away from emotion, because products are often sold (and companies funded) on the basis of customer (or investor) perception, rather than simply cold logic. But the defense of a claim in the profession is seldom successful without heavy "logos" content.

4. The terminology used in the claim is too vague. (Example: "I am a self-starter and team player with outstanding oral and written communications skills.")

   The success of a claim absolutely depends on the words the speaker uses creating the same picture in the minds of the audience that the speaker has. In the profession, vague terms are used all the time:

   • "quality"
   • "progress"
   • "acceptable/unacceptable"
   • "human error"
   • "engineering judgment"

   and I call on the student to define terms like those, make them measurable.

5. Their research involves concepts beyond their present understanding, or includes jargon they can't even pronounce. It's easy for me to tell them not to bother with anything so difficult, but what if they find that part of the argument involves making the rest of us understand what we'd otherwise ignore? (Example: "We must replace methylene chloride with wheat starch media to depaint aircraft safely.")
6. Some people don't understand the term "controversy." This doesn't mean just the kind of sensational controversy that lines the media. Any decision involving two or more choices, where the audience is either undecided on the appropriate choice or is leaning against the speaker, is "controversial." (Example: "aircraft fly over neighborhood A more often than over neighborhood B, so A has a greater noise problem." Is that necessarily so? Whether it is or not, to whom is the question "controversial?")
7. The presenter fails to fully consider the background and state of mind of the audience. The mismatch can be narrow or broad, trivial or consequential. It used to be important to target a presentation to the technical background of the audience. When that's the case, making changes as needed is pretty easy: more jargon (or less), more detail (or less).

   I've often found recently that the technical audience has made up its mind, and is often opposed to your claim. If you must present to such an audience anyway, be careful not to make it worse. Avoid doublespeak, avoid pretentiousness. Breathe and speak smoothly. But don't back off from your claim. The audience must have a chance to judge the claim on its merits, without being distracted by your inability to deal with opposition.

8. The presenter uses trendy terms, or terms with personal meaning -- but which have no objective meaning. (Example: "microstructure." This term has no objective definition, no unit of measure. Like "truth" and "beauty.")
9. The claim is politically biased. (Example: "the company will be saved/destroyed by downsizing.")