Presentation: Fallacies - Relevance vs. Weak Induction
Homework
• Study Fallacies 1-18
– Review pp. 103-132
• Fallacies (definition § 4.1)
• § 4.2 Fallacies of Relevance (1 – 8)
• § 4.3 Fallacies of Weak Induction (9 – 14)
– For Next Class: pp. 139-152
• § 4.4 Fallacies of Presumption & Ambiguity (15 – 22)
Fallacies of Relevance
Relevance vs. Weak Induction
• Fallacies of Relevance
– Premises are logically immaterial to conclusion
– Typical features:
a) tactic of distraction
b) conclusion rests on emotional appeal
– Premises may appear to be psychologically relevant
• Fallacies of Weak Induction
– Premises are relevant to conclusion
– Insufficient evidence to warrant conclusion
Fallacies of Relevance
1. Appeal to Force
2. Appeal to Pity
3. Appeal to the People
–
–
Direct
Indirect
4. Argument against the Person
(Ad hominem)
–
–
–
5.
6.
7.
8.
Abusive
Circumstantial
You, too!
Missing the Point
Of Accident
Straw Man
Red Herring
In each case,
1. The premises are
immaterial to
conclusion
2. Premises often
distract attention
from relevant
evidence
Fallacies of Relevance
• Appeal to the People
– Two Kinds
1. Direct Approach
– Appeal to group
– Appeal to emotions, either positive or negative
– Evidence overlooked due to cloud of emotional attachment
Political speech
2. Indirect Approach
– Appeal to individuals
– Appeal to attachment or relationship to crowd
– Evidence overlooked in favor of emotional attachment
Advertisements
Fallacies of Relevance
• Ad Hominem Arguments (against the person)
– Three varieties
•
Abusive: attack on character of arguer
–
•
Circumstantial: attack by reference to specific
irrelevant circumstances affecting arguer
–
•
Turn attention away from the argument to the arguer
Evidence for proposed conclusions overlooked in such
attacks
You, too!: attack by charge of hypocrisy
–
Irrelevant behavior characteristics overshadow argument
Fallacies of Relevance
• Red Herring (stinky fish)
– Someone diverts attention from subject at hand
• Introduction of a controversial, hot-button issue
• The original argument tied illegitimately to
controversial position (the stinky fish)
– Controversial position attacked for its
outlandishness
Relevance
Weak
Induction
1. 1.
TheThe
premises
premises
are are
immaterial
relevanttotoconclusion
conclusion
2. Premises provide insufficient evidence to warrant
2.
Premises
conclusion
oftenofdistract
attention
from relevant evidence
Example:
Question
Evidence
(red herring)?
Fallacies of Relevance
Appearing on ABC's This Week, the Ohio Republican (Minority Leader
John Boehner) was asked what to describe the GOP plan to dealing
with greenhouse gas emissions, "which every major scientific
organization said is contributing to climate change."
Two Distinct Fallacies
Boehner replied: "The idea that carbon dioxide is a carcinogen that is
harmful to our environment is almost comical. Every time we
exhale, we exhale carbon dioxide. Every cow in the world, you know
when they do what they do you've got more carbon dioxide."
Oversimplification?
Red Herring?
"It's clear we've had change in our climate," he added. "The question is
how much does man have to do with it and what is the proper way
to deal with this? We can't do it alone as one nation."
The Huffington Post, “Boehmer Cites Cow Farts to Downplay Global Warming”
Fallacies of Relevance
• Straw Man
– Someone misrepresents another’s argument
• Presents weaker argument
– Straw man vs. real man
– Attacks weaker argument as if it were the original
• Distorted argument often a fabrication
Fallacies of Relevance
• The Darwinian theory of evolution cannot be
true. Evolution asserts that the human being
is a descendant of certain primate species. My
parents are certainly human, as were theirs.
Just as it is absurd to believe that a human
being could birth a chimpanzee, it is absurd to
believe a monkey could produce a human.
A misrepresentation of Dawinian theory of evolution.
As such irrelevant evidence against.
Fallacies of Relevance
Question of Evidence?
" The most talked-about aspect of the defense case undoubtedly
concerned Mark Fuhrman, the LAPD officer who had found the bloody
glove and who, as a prosecution witness, denied using the word
"nigger." It turned out that Fuhrman had used "the n word"--many
times--and it was on tape. Laura Hart McKinny, an aspiring
screenwriter from North Carolina, had hired Fuhrman to consult with
her on police issues for a script she was writing. McKinny taped her
interviews with Fuhrman, who not only used the offensive racial slur,
but disclosed that he had sometimes planted evidence to help secure
convictions. Needless to say, the defense wanted McKinny on the
stand, and they wanted the jury to hear selected portions of her tapes.
The prosecution strenuously objected, arguing that McKinny's
testimony was irrelevant absent some plausible evidence suggesting
that evidence was planted in the Simpson case. The prejudicial value
of the testimony, the prosecution insisted, would exceed its probative
value.”
The Trial of O.J. Simpson by Doug Linder
Fallacies of Relevance
• Appeal to Force
• Appeal to Pity
• Appeal to the People
– Direct
– Indirect
• Argument against the
Person
– Abusive
– Circumstantial
– You, too!
•
•
•
•
Missing the Point
Of Accident
Straw Man
Red Herring
• Premises are
logically immaterial
to conclusion
• Attention drawn
away from
supporting evidence
– appeal to some
irrelevant concern
– often intentionally
deceptive
• Premises appear relevant
Homework
• Study Fallacies 1-18
– Review pp. 103-132
• Fallacies (definition § 4.1)
• § 4.2 Fallacies of Relevance (1 – 8)
• § 4.3 Fallacies of Weak Induction (9 – 14)
– For Next Class: pp. 139-152
• § 4.4 Fallacies of Presumption & Ambiguity (15 – 22)