Logical Fallacies – Core Lecture Notes

Original full recording was (52\text{ minutes}) long; instructor re-recorded and resumed at slide (11) .
Aim of this shorter lecture: focus on the most common logical fallacies that
- show up in students’ own argumentative essays, and
- begin to appear in non-peer-reviewed sources once research moves beyond scholarly databases (e.g., blogs, news, casual conversations).
Overarching goal: help students
- recognize flawed reasoning patterns in outside sources, and
- avoid reproducing those flaws in their own writing, especially the upcoming rhetorical analysis, proposal, and position papers.

Ego: desire to win an argument or inability to admit wrongness.
Bias: selective exposure to confirming evidence (echo chambers).
Ignorance: sincere unawareness of misinterpretation or misrepresentation.
Inherent human desire for neat solutions: we sometimes "torture" logic to reach an answer when the genuine answer may be ambiguous or unknowable.

Peer-reviewed literature usually filters out blatant fallacies, but popular sources do not.
Students often introduce fallacies inadvertently while trying to strengthen their own stance (e.g., over-generalising, jumping to unrelated conclusions, or fear-mongering).
Identifying these patterns now prevents weaker arguments later.

Drawing a broad, categorical conclusion from limited, atypical, or anecdotal evidence.
Formula: tiny sample / single incident ➔ sweeping statement about an entire group / phenomenon.

Complex realities are flattened into simplistic narratives; research rigor (sample size, representativeness) is ignored.

"My car has gas but won’t start; therefore the gas gauge must be broken" – ignores (\approx 1000) other possible mechanical causes.
"It’s June and I’m wearing a coat – global warming is a sham" – uses one cold day to negate (>100{,}000) peer-reviewed climate studies.
Anecdote: "Uncle smoked (4) packs/day, lived to (92) – cigarettes can’t be that bad."
Alice in Wonderland (Lewis Carroll):
- Salt water ➔ assumes she’s in same sea she once visited.
- Concludes a railway must be nearby because last seaside trip had one.
2011 campaign quote (Herman Cain): discomfort with Muslim cabinet members because "some" Muslims are militant – extrapolates a fraction to entire faith community.
2016 campaign misstep (Clinton): "basket of deplorables" comment – halves Trump supporters into a negative stereotype, alienating potential voters.

Relying on only one pro-gun or anti-gun article, then refuting “opposition” without reading genuine counter-evidence, produces a hasty generalization and weak refutation.

Buddy Burger
- Premise: voted "best food in town" by local paper.
- Conclusion: owner Phil should be mayor.
- Culinary skill ≠ political competence.
Florida Bar Exam practice question
- Aunt wants warm weather & low property taxes.
- Texas rejected for high taxes.
- Therefore she must move to Florida – ignores any other warm, low-tax states.
2011/12 press exchange with Mitt Romney
- Asked how to prove ideological consistency; answers that he has been married (42) years.
- Marriage longevity does not validate policy steadiness.

Students sometimes stack strong evidence on Topic A, then pivot to a policy proposal (Topic C) unrelated to that data, expecting readers to accept the leap.

Asserts that permitting Action A will inevitably trigger extreme negative Outcome Z.
Relies on fear-based conjecture, not causal proof.
Structure: If A, then Z; Z is horrific ➔ Don’t allow A.

Interracial marriage cartoon (post-Loving v Virginia (1967) ): "If Blacks can marry Whites, people will soon marry house pets."
Roe v Wade (1973) caricature: "Legal abortion ➔ legal infanticide any year now." (Rumour persists; traced by instructor to an Onion satire.)
(2003) anti–same-sex-marriage rhetoric: "If gays marry, incest & bigamy are next."
Bully cartoon: Allow bully on lawn today ➔ he will "eat your baby" within (48) hours.

Loving v Virginia oral arguments: opponents equated interracial marriage with polygamy, incest, or child marriage; claimed the ban on interracial unions "stands on the same footing" as bans on those taboos – classic slippery slope strategy.

"If we pass common-sense background-check laws, the government will confiscate all guns by the end of the president’s term" – ignores constitutional hurdles & political realities.

Trace steps between A and Z: Are intermediary stages plausible, evidenced, and likely?
- Bridge-regulation hypothetical: relaxing engineering codes in Louisiana could reasonably culminate in collapses – not a fallacy.
- Pet-marriage or gun-confiscation scenarios: highly improbable, no mechanism outlined – definite slippery slope.

Fallacies weaponize emotion (fear, prejudice) and undermine rational civic discourse.
Over-generalization fuels stereotypes, discrimination, and bad policy.
Non sequiturs distract audiences from substantive evaluation.
Slippery slopes freeze reform by exaggerating risk and stoking panic.

Earlier slides (not in this recording) covered memory experiments showing that minor word-choice tweaks can alter eyewitness recollection – underscores how easily human cognition can be misled, setting the stage for fallacy susceptibility.

Cross-check sample sizes, methodologies, and representativeness before generalising.
Ensure conclusion flows directly from presented premises; draft argument maps.
When projecting consequences, supply step-by-step causal chains and empirical precedent.
Seek out disconfirming evidence to counter personal ego/bias.
Have peer reviewers flag leaps, stereotypes, or scare tactics.

Logical fallacies stem from normal human motivations but degrade argument quality.
Mastery involves both detection and disciplined avoidance in one’s own prose.
Today’s focus: Hasty Generalization, Non Sequitur, Slippery Slope – three of the most common in student writing and public rhetoric.
Further fallacies will be introduced as the course progresses; keep annotating examples in your reading notes.