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3. Rhetoric

 

Summary​

Rhetoric is the art of persuasion. A central theme of the course is the distinction between proof and persuasion: logic gives logical reasons for the truth of a claim, while rhetoric uses techniques that work psychologically and need not involve reason at all. Good critical thinkers learn to tell the two apart.

Clarity and four causes of confusion​

Clear communication conveys meaning accurately. Clarity is threatened by four things:

  • Vagueness – a term whose meaning is excessively inexact, with fuzzy borders (bald, rich, fast, "do a good job"). Some vagueness is normal and acceptable; it becomes a problem only when it makes a claim impossible to assess.
  • Ambiguity – a claim that could carry more than one meaning without contextual clues. Three kinds:
    • Semantic ambiguity (equivocation) – one word has multiple meanings (e.g. "our mothers bore us"; the Who's on First? routine).
    • Syntactic ambiguity (amphibology) – grammar/word order creates two readings ("I shot an elephant in my pajamas").
    • Grouping ambiguity – confusion over whether a term is used collectively or distributively (the basis of the later composition fallacy). Ambiguity can be unintentional (fix it with care) or intentional (used to mislead or to soften a response).
  • Generality – too broad, supplying too little detail ("no animals allowed").
  • Undefined terms – cured by defining terms (see below).

Defining terms​

Definitions serve four purposes: to give a word's meaning, to fix meaning in a context, to reduce vagueness/generality/ambiguity, and to persuade. By purpose, the main types are:

  • Lexical – the ordinary dictionary meaning.
  • Explanatory – unpacks the implications of a known but difficult concept.
  • Stipulative – assigns a meaning for a particular context ("in this class we will use the word legend to mean…").
  • Precising – narrows an unclear term to reduce ambiguity (defining walking vs running by keeping a foot on the ground).
  • Rhetorical (persuasive) – a pseudo-definition that works on feelings via connotation ("casualties refers to our sons and daughters killed in battle").

By manner, definitions can be analytical (denotative: the necessary/sufficient features a thing must have), by example (ostensive: pointing to an instance), or by synonym (dog → canine).

Writing argumentative essays​

A good argumentative essay should: state the issue, state your position, support it with reasons (not just assertions), and address the strongest opposing positions. Tackling the best counter-arguments, not weak ones, makes your case stronger. Thomas Aquinas's method is the model: pose the question, list objections up front, give a short rebuttal, present the body of the argument, then reply to each objection in detail.

Judging credibility​

When a claim is presented, evaluate both the claim itself and its source.

  • The claim – assess its initial plausibility: how well it squares with our background information and direct experience. ("Ginseng makes kids grow faster" has low plausibility; "the tank still has fuel after the warning light" has high plausibility.)
  • The source – credibility rests on knowledge, truthfulness, accuracy, and objectivity. Be more suspicious of an interested party (someone who stands to gain) than a disinterested one. Expertise raises credibility, and expert claims generally outweigh amateur ones, but experts can be wrong and often disagree (the later appeal to authority fallacy). Where you can make the same direct observation yourself, you need not defer to the expert.

Aristotle's modes of persuasion​

Aristotle defined rhetoric as observing the available means of persuasion, and identified three modes:

  • Ethos – the speaker's character and reputation.
  • Pathos – putting the audience in a certain emotional frame of mind.
  • Logos – proof through reasoning and supporting premises.

He also gave the five canons of rhetoric: invention (developing arguments), arrangement, style, memory, and delivery (tone, pace, body language). Logic and rhetoric were the twin anchors of Western education: logic demonstrates truth, rhetoric wins people over. A valid argument may still fail to persuade, and persuasion can succeed without proving anything.

Rhetorical devices​

These use emotionally loaded language to influence beliefs and feelings without genuine proof. Grouped roughly:

  • Slanters (better/worse/shielding) – euphemisms vs dysphemisms (escort vs thug), weaselers that hedge to avoid criticism ("as far as I know", "perhaps"), and downplayers that minimize ("merely", "so-called", scare quotes).
  • Unwarranted assumptions – stereotypes (over-generalizations about a group), innuendo (implying without stating: "far be it from me to call my opponent a liar"), and loaded questions ("have you stopped beating your wife?").
  • Humor and exaggeration – ridicule / sarcasm (mocking a position instead of refuting it) and hyperbole ("dumber than a rock"; calling conservatives fascists or liberals communists).
  • Comparisons and surrogates – rhetorical definitions/explanations and misleading analogies/comparisons (ask: is key information missing? is the same standard used?), plus proof surrogates ("obviously…", "reliable sources say", "everybody knows") and repetition, a staple of propaganda.

Images​

Finally, images are never true or false, they are not claims, yet they powerfully elicit responses and are easily doctored or digitally manipulated to plant a false impression. This sets up the next lecture on advertising.