vs Relevance Homework Reading pp 145152 Recommended Exercises do at least the starred problems 43III of relevance amp weak induction 44I of presumption amp ambiguity ID: 279834
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Slide1
Presentation: Fallacies - Presumption
vs.
RelevanceSlide2
Homework
Reading: pp. 145-152
Recommended Exercises
(do at least the starred problems)4.3.III (of relevance & weak induction)4.4.I (of presumption & ambiguity)4.4.III: 1-50
RememberHow does each specific argument commit a fallacy of that type? Where precisely is the offending element in the argument?
The Study Guide is available online
Model exercise for the examSlide3
Kinds of Informal Fallacies
Fallacies of:
Relevance
Weak InductionPresumptionAmbiguity or Whole/PartAmbiguity
Whole/PartWhere premises do support the conclusionInsufficient evidence to warrant conclusionConclusion unlikelyFallacies of inductionSlide4
Kinds of Informal Fallacies
Fallacies of:
Relevance
Weak InductionPresumptionAmbiguity or Whole/PartAmbiguity
Whole/PartPremises are logically immaterial to conclusion Attention drawn away from supporting evidence appeal to some irrelevant concernoften intentionally deceptivePremises appear relevantSlide5
Kinds of Informal Fallacies
Fallacies of:
Relevance
Weak InductionPresumptionAmbiguity or Whole/PartAmbiguity
Whole/PartPremises reiterate or presuppose conclusionSimple or deceptiveMay also presume what needs provingSlide6
Fallacies of Presumption
Begging the Question
Complex Question
Either … or … (false dichotomy)Suppressed Evidence
Formally, identical to valid argumentsSlide7
Fallacies of Presumption
Begging the Question
Conclusion is restatement of some premise
Simple: In same wordsComplex: In different words of same meaningDeceptive: Key premise missing but asserted as premiseCircular argumentPremises presuppose conclusion which, itself, presupposes premisesSlide8
Fallacies of Presumption
P
⊢
P
1 (1) P ASlide9
Fallacies of Presumption
BQ (restatement)
We have a brain in our skulls but no mind. The mind is a myth, since the mind is just a fairy tale we tell ourselves to believe in life after death.
A myth and a fairy tale are one and the same thing
Shaky premiseSlide10
Fallacies of Presumption
Circular Reasoning
To cast abortion as a solely private moral question…is to lose touch with common sense: How human beings treat one another is practically the definition of a public moral matter. Of course, there are many private aspects of human relations, but the question whether one human being should be allowed fatally to harm another is not one of them. Abortion is an inescapably public matter.
Source: Helen M. Alvaré, The Abortion Controversy, Greenhaven, 1995, p. 23.(http://www.fallacyfiles.org/begquest.html)Slide11
Fallacies of Presumption
Circular Reasoning
To cast abortion as a solely private moral question…is to lose touch with common sense
: How human beings treat one another is practically the definition of a public moral matter. Of course, there are many private aspects of human relations, but the question whether one human being should be allowed fatally to harm another is not one of them. Abortion is an inescapably public matter.Source: Helen M. Alvaré, The Abortion Controversy, Greenhaven, 1995, p. 23.(http://www.fallacyfiles.org/begquest.html
)Slide12
Fallacies of Presumption
Circular Reasoning
To cast abortion as a solely private moral question…is to lose touch with common sense: How human beings treat one another is practically the definition of a public moral matter. Of course, there are many private aspects of human relations, but
the question whether one human being should be allowed fatally to harm another is not one of them. Abortion is an inescapably public matter.Source: Helen M. Alvaré, The Abortion Controversy, Greenhaven, 1995, p. 23.(http://www.fallacyfiles.org/begquest.html
)Slide13
Fallacies of Presumption
Circular Reasoning
To cast abortion as a solely private moral question…is to lose touch with common sense:
How human beings treat one another is practically the definition of a public moral matter. Of course, there are many private aspects of human relations, but the question whether one human being should be allowed fatally to harm another is not one of them. Abortion is an inescapably public matter.Source: Helen M. Alvaré, The Abortion Controversy, Greenhaven
, 1995, p. 23.(http://www.fallacyfiles.org/begquest.html)Abortion is a public matter.Why?Abortion is a not a private matter.Slide14
Fallacies of Presumption
“Either … or …” fallacy
You should just drop out of school. Either take a full course load or drop out. And with everything going on right now you can’t take a full course load.
Standard Features:Express disjunctionReasonable alternatives ignored or suppressed
PvQ, ~P ⊢ Q1 (1) P v Q A2 (2) ~P A1,2 (3) Q 1,2 vESlide15
Fallacies of Presumption
Complex
Question
After J. Gordon Liddy served time in prison for his role in the Watergate scandal that brought down President Nixon, he made an appearance on the Dick Cavett show. On the show, Cavett mentioned the high rate of homosexual activity in US prisons.Cavett: “Did you have any trouble adjusting to homosexuality in prison?” Liddy: “No.”
Cavett: “There you have it folks. Mr. Liddy had no trouble adjusting to homosexuality in prison.”The two questions in one:Did you adjust to a homosexual lifestyle in prison?Was it difficult?Slide16
Fallacies of Presumption
Suppressed Evidence
Cough syrup is an effective remedy for adults suffering from common respiratory distress. Kids will benefit as equally.
Recognition of suppressed evidence can be challenging?Obvious instances are, of course, simple to identifyMore difficult cases: background knowledge often necessarySlide17
Fallacies of Presumption
"The Second Amendment to the Constitution states that the right of the people to keep and bear arms shall not be infringed. But a law controlling handguns would infringe the right to keep and bear arms. Therefore, a law controlling handguns would be unconstitutional.
"In fact, the Second Amendment reads, "A well regulated militia being necessary to the security of a free state, the right of the people to keep and bear arms shall not be infringed." In other words, the amendment states that the right to bear arms shall not be infringed when the arms are necessary for the preservation of a well-regulated militia. Because a law controlling handguns (pistols) would have little effect on the preservation of a well-regulated militia, it is unlikely that such a law would be unconstitutional. (
p. 146 of our text)Slide18
Fallacies of Presumption
"The Second Amendment to the Constitution states that the right of the people to keep and bear arms shall not be infringed. But a law controlling handguns would infringe the right to keep and bear arms. Therefore, a law controlling handguns would be unconstitutional.
"In fact, the Second Amendment reads, "
A well regulated militia being necessary to the security of a free state, the right of the people to keep and bear arms shall not be infringed." In other words, the amendment states that the right to bear arms shall not be infringed when the arms are necessary for the preservation of a well-regulated militia. Because a law controlling handguns (pistols) would have little effect on the preservation of a well-regulated militia, it is unlikely that such a law would be unconstitutional. (p. 144 of our text)Slide19
Fallacies of Presumption
"The Second Amendment to the Constitution states that the right of the people to keep and bear arms shall not be infringed. But a law controlling handguns would infringe the right to keep and bear arms. Therefore, a law controlling handguns would be unconstitutional.
"In fact, the Second Amendment reads, "A well regulated militia being necessary to the security of a free state, the right of the people to keep and bear arms shall not be infringed." In other words, the amendment states that the right to bear arms shall not be infringed when the arms are necessary for the preservation of a well-regulated militia. Because
a law controlling handguns (pistols) would have little effect on the preservation of a well-regulated militia,
it is unlikely that such a law would be unconstitutional. (p. 144 of our text)"The Supreme Court, splitting along ideological lines, on June 26 <2008> declared the District of Columbia's ban on handgun ownership unconstitutional." (Washington Post)http://www.washingtonpost.com/wp-dyn/content/story/2008/06/23/ST2008062300649.html?hpid=topnews Slide20
Homework
Reading: pp. 145-152
Recommended Exercises
(do at least the starred problems)4.3.III (of relevance & weak induction)4.4.I (of presumption & ambiguity)4.4.III: 1-50
The Study Guide is available onlineModel exercise for the exam
Remember
How
does each specific
argument commit a fallacy of that type?
Where precisely is the offending element in the argument
?