FALLACIES
FALSE OR ILLOGICAL ARGUMENTS THAT OFTEN, AT
FIRST, APPEAR TO MAKE SENSE
THREE CATEGORIES
Interpreting
Evidence
• Hasty
Generalization
• Non Sequitur
• Post Hoc, Ergo
Propter Hoc
• Of the Beard
• False Analogy
• Bandwagon
Evading Evidence
Black or White
Oversimplification
Apriorism
Impossible
action/appeal for
perfection
• Appeal to
emotion
•
•
•
•
Diversionary
Tactics
• Ad Hominem
• Poisoning the
Well
• Distraction
• Abandonment
of Discussion
• Pointing to
another wrong
• Appeal to
Ignorance
• Circular
Reasoning
INTERPRETING EVIDENCE
• Common characteristic:
• “People Fallacies”
• People make these mistakes from evidence to conclusion
through insufficient evidence and lack of relevant
reasoning.
FALLACY OF HASTY GENERALIZATION
• Making a generalization or conclusion based on
insufficient evidence
• "All teens are ...... because I saw one .......
• "Girls are horrible drivers.“
FALLACY OF NON-SEQUITUR
• Latin for “it does not follow”
• Conclusion does not logically follow from the
evidence
• No relevant connection between evidence and conclusion
(or cause/effect)
• Most common fallacy
• “I didn’t do my homework last night because my dog
needed a bath”
FALLACY OF POST HOC, ERGO PROPTER
HOC
• Latin for “after this, therefore because of this”
• Based on irrelevancies
• if A precedes B, it need not therefore be the cause
of B, even though we may lazily assume it is
• A may have been the only sufficient cause of B
• A may have been one of several necessary causes
• A and B may be entirely coincidental
POST HOC, ERGO PROPTER HOC
EXAMPLE
• conclusion is based on a very recent event that has
no evidence to establish a connection between
event and effect
• "Since that new school was built, drug use among our teens
has skyrocked. Better that it would never have
been
built.“
• falsely argued cause-to-effect or effect-to-cause relationship
FALLACY OF THE BEARD
• Name
derived from
ancient
Greek
Philosophers
who
pondered
how many
hairs it took
to make a
beard
• Answer is
different in
China than
America
• Domino Effect
• chain-reaction argument where one
force (cause) produces one effect, and
then goes on to predict the same cause
will produce numerous other effects
• attempts to make future predictions
• If students move computers in school, they
may be held liable if they damage the
computer. In the process of damaging the
computer, students may injure themselves
or others. The injured student/s could then
sue the school, in which case the school
may suffer in terms of teacher salary,
equipment it can afford, and ultimately, the
quality of education students receive.
FALLACY OF FALSE ANALOGY
• comparison between two things where the relevant
differences outnumber the real similarities
• analogy weakens an argument if improper, if
grounds for comparison are too vague, or if the
analogy is stretched too far
• School is like prison.
FALLACY OF THE BANDWAGON
• an action is urged, and the reason/evidence for
that action is simply that others are doing it
• appeals to everyone's sense of wanting to belong
or be accepted
• Everyone on the team wears hightops; it's the only
way to go.
THREE CATEGORIES
Interpreting
Evidence
• Hasty
Generalization
• Non Sequitur
• Post Hoc, Ergo
Propter Hoc
• Of the Beard
• False Analogy
• Bandwagon
Evading Evidence
Black or White
Oversimplification
Apriorism
Impossible
action/appeal for
perfection
• Appeal to
emotion
•
•
•
•
Diversionary
Tactics
• Ad Hominem
• Poisoning the
Well
• Distraction
• Abandonment
of Discussion
• Pointing to
another wrong
• Appeal to
Ignorance
• Circular
Reasoning
EVADING EVIDENCE
• Common characteristics:
• Basic disregard for evidence
• Judgments are based on emotions or previously
held beliefs
• Based on some evidence, but not substantive evidence.
FALLACY OF BLACK AND WHITE
• Oversimplification of issue where answer is one
extreme or the other
• Opposite ends: black/white or good/bad
• Fails to recognize wide range of possibilities
• EX: You are either with me, or against me.
FALLACY OF OVERSIMPLIFICATION
• A subdivision of “Fallacy of Black or white”
• Does not indicate choices between two extremes
• Takes complex problem, comes to a quick and easy
solution
• Solution is not based in evidence, and usually does not solve
problem– can worsen it
• Ex: The best way to solve rising traffic deaths is to
get of liquor in our country.
FALLACY OF APRIORISM
• “a priori”= Latin for “before”
• conclusion is based on a previously held belief,
despite the fact that there is new, objective
evidence that should change the original belief
• I refuse to use public restrooms or public drinking
fountains. Everybody knows that these places are a
harbor for germs, especially the HIV virus. There is
no way I will risk getting a disease like AIDS just
because I am thirsty or need to use the restroom.
FALLACY OF IMPOSSIBLE
ACTION/APPEAL FOR PERFECTION
• Ignores human condition by arguing that a problem
can be solved by an impossible action
• nothing needs to be done now--the problem will solve itself
(when there is perfection on earth)
• often 'non-sequitur' fallacy as well because conclusion
does not follow from evidence
• EX: Indian gaming casinos: are they right or wrong?
With the upsurge of Christianity on reservations, the
Indians will surrender their hearts and wills to God,
and He will act through their conscious.
FALLACY OF APPEAL TO EMOTION
• Substitute emotional appeal for proper evidence
and reasoning.
• Emotion-packed words used in lieu of evidence
• Pity, fear, love, pride, tradition, patriotism
• People often do make decisions and take actions based on
feelings rather than sound logic.
• Advertising!
THREE CATEGORIES
Interpreting
Evidence
• Hasty
Generalization
• Non Sequitur
• Post Hoc, Ergo
Propter Hoc
• Of the Beard
• False Analogy
• Bandwagon
Evading Evidence
Black or White
Oversimplification
Apriorism
Impossible
action/appeal for
perfection
• Appeal to
emotion
•
•
•
•
Diversionary
Tactics
• Ad Hominem
• Poisoning the
Well
• Distraction
• Abandonment
of Discussion
• Pointing to
another wrong
• Appeal to
Ignorance
• Circular
Reasoning
DIVERSIONARY TACTICS
• Common Characteristics:
• Introduce escape manipulations or “Diversionary tactics”
• Argumentative device that smokescreens/evades real issues of
argument
• Attempt to discredit person who has argument
• Point to another, irrelevant issue and claim improper wrong
to debate introduced issue
FALLACY OF AD HOMINEM
• Latin for “to the man”
• Refusal to confront issues; confronts person
• Discredits character, reputation, or motives
• Use name calling
• Ex: I don’t know who this guy is, but he sounds like a
fool to me.
FALLACY OF POISONING THE WELL
• Subdivision of Ad Hominem fallacy
• Difference: discredit the source before the argument is
presented, not after
• Ex: Now it’s time to hear your side of the story, and
we can just guess what your remarks are going to
be. Audience, please bear with us during this flight
of fantasy.
FALLACY OF DISTRACTION
• Introduces new ideas that are not related
• Uses two ploys
• Humorous/sarcastic comment
• Direct question back to arguer/questioner
• EX: a couple is arguing about a perceived flirtation
with another woman. The girl brings up the fact that
her significant other rarely returns her phone calls in
a timely manner.
FALLACY OF ABANDONMENT OF
DISCUSSION
• Form of distraction fallacy
• Act of refusing to argue or listen to opposing views
• Since issue is a tradition, it would be improper to question or
discuss it
• Simply refuse to argue
• Ex: There is no need to bring up sex education in
schools because the idea is immoral
FALLACY OF POINTING TO ANOTHER
WRONG
• Form of distraction fallacy
• Accused person presents defense by pointing to a
wrong or fault in person who started argument
• Two wrongs don’t make a right
• EX: Student fails his test. He argues that since others
did very poorly on the test as well, it was not his
fault.
FALLACY OF APPEAL TO IGNORANCE
• It’s not true because it cannot be disproved
• Santa Claus
• Just because you’ve never seen Santa doesn’t make him
imaginary, just like the fact that you’ve not seen $5 million
doesn’t mean it doesn’t exist.
• It is false because it can not be proved
• UFOs do not exist! If they do, show me one piece of
evidence
FALLACY OF CIRCULAR REASONING
• Appears to have all requirements of proper
argument
•
conclusion, signpost, evidence
• Evidence for conclusion is the same or means the
same as the conclusion itself
• EX: Capital punishment is justified because we have
a long history of putting to death people who
commit heinous crimes.