Logic and Scientific Thinking

Misinformation

Bogdan G. Popescu
bgpopescu@tec.mx

Tecnologico de Monterrey

Welcome

Learning Outcomes

  1. Locate the failure: the premises — false, or stripped of scope — vs. the link.
  1. Diagnose the gallop as a tactic, not a fallacy — four criteria before the name.
  1. Apply the defense: pick one claim, demand its evidence — and inoculate.

Recap

Question Answer from the previous sessions
The four families? Faulty reasoning · misused sources · distorted claims · emotional appeals
The three-step diagnosis? Name the move · quote the words · say what would decide it
What did every fallacy attack? The link between premises and conclusion — mostly

Today’s question: what if the premises are the problem?

Misinformation

What Is Misinformation

  • False or misleading information, presented as fact.
    • A fact: a checkable claim that survives the check. Misinformation only looks like one.
  • It can sit inside a perfectly valid argument.
    • Valid: if the premises are true, the conclusion must follow.
  • The new question: are the premises true?

From earlier sessions: valid form + true premises = sound. Misinformation attacks the premises.

Where Arguments Fail

An argument has only two points of attack (Schopenhauer, The Art of Controversy, 1896):

The target Its name The toolkit
The link — “the conclusion doesn’t follow” fallacy — formal or informal validity · the twins · the families
The premises — his “grounds” misinformation fact-checking · sources

Everything else in his manual is conduct: tricks on the checker, not defects in the argument.

Today’s example of conduct: the Gish gallop — a tactic that hides both failures at once.

Bad Premises

(An invented scenario — a classroom specimen.)

P1. If a cafeteria scores below 60 on its health inspection, the university must close it.
P2. “Our cafeteria scored 42.”
C. The university must close our cafeteria.
  • Check the link: modus ponens
  • Every tool from the fallacy sessions comes back clean.
  • So where is the failure?

Bad Premises

P1. If a cafeteria scores below 60 on its health inspection, the university must close it.
P2. “Our cafeteria scored 42.” → the actual inspection report: 92.
C. The university must close our cafeteria.
  • Misinformation is the wrong number — not the wrong connection.
  • A perfect form, fed false input.
  • The premise is just false.

True Words, Misleading Scope

The study: “Among 120 adults with mild symptoms, the treatment reduced self-reported pain by 8% over twelve weeks.”

The headline: “Scientists prove the treatment works.”

  • No quoted number is false.
  • The qualifiers vanished: which people · which outcome · how much · how long.

Misinformation can be manufactured by subtraction.

The Gallop, Checked

P1. “scored 42” → the number is false (the report says 92).
P2. “food poisoning” → asserted, not shown — was it even the cafeteria?
P3. “staff not certified” → what’s the link to the closure rule? Never stated.
P4. “prices went up” → the connection is missing entirely.
  • One false premise + three claims that never connect — the flood hides both failure types.
  • Each check is cheap alone. Four at once, at speed, is the tactic.

The Debate, Again

This time, don’t follow the argument — count the claims.

The Flood

So — how many checkable claims did you just hear?

1917 · 313 ships · 285 ships · “the low 200s” · sequestration · the Air Force since 1947 · FDR · two conflicts at once · a trillion dollars · Congress proposed it · “it will not happen” · maintaining spending · 1916 · horses · bayonets · aircraft carriers · nuclear submarines · the Joint Chiefs · veterans’ support · “your budget doesn’t work”

In those keywords: a claim about every 7 seconds.

Is that a fallacy?

  • Not necessarily — a dense answer can be honest.

But volume used deliberately, with claims too weak to survive checking — that tactic has a name.

Calling a Gallop

Many claims alone is not a gallop. Before using the name, show:

  1. Who is doing it — name the speaker, not the exchange.
  2. Speed: claims arrive faster than the format allows rebuttal.
  3. Strategy: the quantity itself, not the content, is meant to persuade.
  4. Weakness: several claims would not survive checking.

So what? Volume works on the checker — next: why it works, psychologically.

Why It Works

Why Flooding Works

Why can a flood work? Three documented mechanisms:

  • We accept before we reject.
    • You can’t understand “the ball is red” without briefly picturing it — believing is automatic; doubt is a second step. (Gilbert et al. 1993)
  • Quantity can look like quality.
    • When people are not examining arguments closely, more reasons can seem more persuasive. (Petty & Cacioppo 1984)
  • Confidence sounds like competence.
    • A confident speaker may seem more competent, even when that confidence is misplaced. (Price & Stone 2004)

Why Flooding Works

The flood exploits all three:

  • too fast to reject
  • too much to evaluate
  • too confident to dismiss.

The Cost of Checking

Not stupidity — economics:

  • Accepting a claim is free. Checking it is work: understand → reason → decide.
  • Under a flood of claims, the cheap option wins — rationally.
  • You felt it during the debate clip — twice now.

Your capacity to check claims is finite — and floods are designed to exhaust it.

The Defense

Beating the Flood

%%{init: {"theme":"neutral","themeVariables":{"fontSize":"16px"},"flowchart":{"useMaxWidth":true,"nodeSpacing":50,"rankSpacing":50}}}%%
flowchart LR
  C["false claim<br/>cheap to make"] --> U["unprepared:<br/>believes it"]
  U --> R["repetition<br/>feels true"]
  R --> RB["rebuttal<br/>(costly, late)"]
  RB --> P["belief<br/>persists"]
  C --> I["inoculated:<br/>knows the trick"]
  I --> D["met with<br/>suspicion"]
  style P fill:#f3ded9,stroke:#b44527,color:#b44527
  style I fill:#cfe0d8,stroke:#4a7c6f
  style D fill:#cfe0d8,stroke:#4a7c6f

The defense:

  • name the tactic aloud
  • pick one representative claim
  • demand its evidence
  • refuse to chase the other twenty.

Inoculation, Tested

A false claim is about to reach your friend: “the cafeteria scored 42.”

  • No preparation → your friend hears the claim without knowing how to evaluate it.
  • Supportive defense → “The cafeteria has a good safety record.”
    • This strengthens the existing belief but does not answer the coming claim.
  • Refutational inoculation →
    • “You may hear that it scored 42.
    • Ask to see the inspection report: the official score is 92.”

Move 3 is inoculation — sixty years of studies favor it; promising, not established (McGuire 1961; Banas & Rains 2010).

Exercise — Build a Gallop

In pairs (6 min):

  1. Build (3 min): flood a harmless claim — “our cafeteria is the best in the city” — with 8+ quick claims: numbers, names, dates, comparisons. Weak is fine; fast is the point.
  2. Swap & defend (3 min): pick one of their claims, demand its evidence — and refuse to chase the rest.

Debrief: how did flooding feel from each side? — producing the tactic trains detecting it.

Conclusion

Where is the failure?

  • Schopenhauer’s map: two targets — premises and link; everything else is conduct.
  • Misinformation — false premises: a wrong number, or true words minus their scope.
  • The gallop — the conduct example: volume that hides both failures at once.
  • Calling it takes the four checks — overload felt is not strategy shown.
  • Checking capacity is finite — floods are designed to exhaust it.
  • The defense: one claim, its evidence — and inoculation before exposure.

Homework: find one real flood — and run the four checks on it.

References

  • Banas, J. A., & Rains, S. A. (2010). A meta-analysis of research on inoculation theory. Communication Monographs, 77(3), 281–311.
  • Gilbert, D. T., Tafarodi, R. W., & Malone, P. S. (1993). You can’t not believe everything you read. Journal of Personality and Social Psychology, 65(2), 221–233.
  • McGuire, W. J. (1961). The effectiveness of supportive and refutational defenses in immunizing and restoring beliefs against persuasion. Sociometry, 24(2), 184–197.
  • Petty, R. E., & Cacioppo, J. T. (1984). The effects of involvement on responses to argument quantity and quality: Central and peripheral routes to persuasion. Journal of Personality and Social Psychology, 46(1), 69–81.
  • Price, P. C., & Stone, E. R. (2004). Intuitive evaluation of likelihood judgment producers: Evidence for a confidence heuristic. Journal of Behavioral Decision Making, 17(1), 39–57.
  • Schopenhauer, A. (c. 1831/1896). The Art of Controversy (T. B. Saunders, Trans.). Swan Sonnenschein.