Fallacies of Presumption, Ambiguity, and Illicit Transference – Study Notes

Clarifying Weak vs. Strong Analogies

• Strength heuristic
  • More relevant similarities between two cases → stronger analogy.
  • More (or more significant) differences → weaker analogy.
• Problem of “borderline” cases
  • When parallels are chiefly symbolic or metaphorical it can be hard to rate strength.
  • Example revisited from §3.3: “Boiling-point” of water vs. social “boiling-point” that drives citizens to revolt.
  • Physical boiling = \text{heat}\; + \; \text{pressure} \; \Rightarrow \; \text{phase-change / explosion}.
  • Social boiling = \text{oppression}\; + \; \text{pressure} \; \Rightarrow \; \text{revolt}.
  • Literal similarities are absent; figurative similarities (pressure ⟶ critical change) may still make the analogy rhetorically strong.
• Two broad kinds of analogies
  1. Scientific / literal analogies
  • Compare entities of the same kind, focusing on shared empirical properties.
  • Salmon example (pattern induction):
    • Instance 1: eat salmon → get sick.
    • Instance 2: eat salmon → get sick.
    • Predictive inference: Instance 3: eat salmon → (probably) get sick.
  1. Figurative / illustrative analogies
  • Compare entities of different kinds to make an abstract point vivid.
  • Mark Twain: “The difference between the right word and the almost-right word is the difference between lightning and the lightning bug.”
  • Goal = illuminate severity/importance, not claim literal overlap.
• Assessment guideline
  • Ask: Does the figurative comparison help the audience grasp the force or structure of the target claim?
  • If yes → reasonable (strong-enough) analogy; if no → weak analogy.
  • Judgement can legitimately differ among interpreters, but criticism should focus on rhetorical efficacy, not on absence of literal sameness.

Fallacies of Presumption

• Premises try to “sneak in” what must actually be proved.
• Four main types
  • Begging the Question (Petitio Principii)
  • Complex Question
  • False Dichotomy
  • Suppressed Evidence

Begging the Question

• General pattern: arguer creates illusion that premises alone justify conclusion, when in fact they illicitly rely on the conclusion.
• Three classic varieties (Hurley):
  1. Key (often controversial) premise is left unstated.
  • Murder argument
    • P: “Murder is morally wrong.”
    • (Hidden P): “Killing and eating animals = murder.”
    • C: “Therefore, killing and eating animals is wrong.”
    • Hidden premise is controversial & undefended.
  • Taxing the wealthy argument
    • P: “Wealthy people earn more than average citizens.”
    • (Hidden P): “Those who earn more should not be taxed more.” ← Needs evidence.
  1. Conclusion merely restates a premise (verbal camouflage).
  • Capital-punishment example: “It is justified because it is legitimate and appropriate.”
    • “justified” = “legitimate & appropriate” → no new support.
  1. Circular reasoning (statement chain ends up where it began).
  • SKT wireless commercial:
    • P1: “SKT has the best wireless service.”
    • P2: “Therefore, clearest sound.”
    • P3: “Customers hear better → must be best wireless.”
    • P4: “Digital technology explains this, which you’d expect from the best wireless.”
    • The conclusion literally re-invokes P1 → no independent starting point.
• Not every restatement is fallacious
  • If premise is true and argument form is valid, the argument is sound though trivial (e.g. “No dogs are cats. Therefore, no cats are dogs.”).

Complex Question

• Two (or more) questions fused into one; replying "yes" or "no" tacitly grants a presupposition.
• Structure: Presupposition → Forcing acknowledgment.
• Cheating example: “Have you stopped cheating on exams?”
  • “Yes” → you used to cheat.
  • “No” → you still cheat.
• Contains an implicit argument extracting admission from any direct answer.

False Dichotomy (False Dilemma)

• Form: P \lor Q (either/or) + ¬P ⇒ Q (or symmetrical).
• Error: disjunctive premise is not jointly exhaustive.
• Concert example: “Either you let me go or I’ll be miserable forever.”
  • Ignores alternatives (e.g. short-term disappointment, alternative activities, improved mood later, etc.).
• Argument is formally valid but unsound due to false P \lor Q.

Suppressed Evidence (Cherry Picking)

• Important contrary evidence is left out; premises appear complete but are not.
• Dog example: “Most dogs are friendly → safe to pet this one.”
  • Suppressed: dog is foaming at mouth (possible rabies).
• Cassette-player argument: fewer cassette players today ⇒ people listen to less music.
  • Ignores new listening media (MP3, streaming).
• Contrast with begging the question:
  • Begging = omitted premise is needed to support the SAME conclusion.
  • Suppressed evidence = omitted premise would support a DIFFERENT conclusion.

Fallacies of Ambiguity

• A word/expression is used with >1 sense within the argument.
• Two major sub-types.

Equivocation

• Same lexical item appears multiple times with different meanings.
• “Law” example
  • P1: Any law₁ (statute) can be repealed.
  • P2: Gravity is a law₂ (natural).
  • C: Gravity can be repealed.
• “Large mouse” example
  • ‘large’ (relative to mice) vs. ‘large’ (relative to animals in general).

Amphiboly

• Ambiguity due to sentence structure (syntactic/grammatical).
• Pattern
  1. Someone’s statement S is quoted.
  2. Arguer selects an unintended reading of S.
  3. Conclusion drawn from misreading.
• Statue of Liberty example
  • Statement: “Standing in Greenwich Village, the Statue of Liberty could easily be seen.”
  • Misread: Statue is located in Greenwich Village.
• Pronoun-antecedent example
  • “John told Henry that he had made a mistake.”
  • Ambiguity of ‘he’ (John vs Henry) exploited.

Fallacies of Illicit Transference

• Mis-attributing properties between parts and wholes.
• Two directions.

Composition

• Features of parts wrongly projected onto whole/class.
• Team example: every player is excellent ⇒ team is excellent.
  • Overlooks teamwork, coordination.
• Cup made of invisible atoms ⇒ cup is invisible.
• Distinction from Hasty Generalization
  • Hasty Gen: moves from some instances to a universal claim about all members (distributive predication).
  • Composition: moves from members to claim about the group as a single entity (collective predication).
  • Flea illustration
  • “Fleas are small” (general statement) vs. “Fleas are numerous” (class statement).
  • Car vs. fire-truck fuel example: because each car uses less fuel than each fire truck → class of cars uses less fuel overall (false).

Division

• Reverse of composition: attribute whole’s property to each part/member.
• Airplane example: plane made in Seattle ⇒ every part made in Seattle (false).
• Royal Society: society is 300 years old ⇒ any member is 300 years old (false).

Practical & Philosophical Implications

• Reasoning quality affects ethical, economic, scientific, and political decision-making.
  • Mislabeling metaphor as literal (weak analogy) can mislead policy debates.
  • Begging the question commonly occurs in moral/ideological arguments—vigilance prevents dogmatism.
  • False dilemmas often fuel propaganda by obscuring nuanced alternatives.
  • Suppressed evidence corrodes fair inference in journalism and scientific reporting.
  • Ambiguity fallacies highlight importance of precise language in law and academia.
  • Illicit transference warns against naïve aggregation (e.g. ecological fallacy, Simpson’s paradox).

Key Take-away Checklist for Exam

• When assessing an argument, ask sequentially:
  1. Are premises presumptively smuggling in the conclusion (begging, complex, dichotomy, suppression)?
  2. Is any term or syntax switching meaning mid-argument (equivocation, amphiboly)?
  3. Are properties being illegitimately transferred between parts/whole (composition, division)?
• Use the specific sub-class tests:
  • Begging: missing premise? paraphrased premise? loop?
  • Complex Q: would each possible answer concede an un-agreed claim?
  • False Dichotomy: can you think of a third live option?
  • Suppressed Evidence: does known contrary data change probability of conclusion?
  • Equivocation: underline repeated words—are senses constant?
  • Amphiboly: locate ambiguous punctuation/pronoun placements.
  • Composition/Division: ask “distributive or collective?”
• Whenever formal validity (P \lor Q, \; \neg P \Rightarrow Q) shows up, double-check truth of disjunctive premise.
• Remember: Soundness = Validity + all true, complete premises.
• Avoid trivial but non-informative tautologies; aim for informative, independently supported arguments.