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Chapter 3 - Clarifying Meaning
THE PRINCIPLE OF CHARITY
principle of charity: to find the fairest and most plausible interpretation of
a speaker’s statement
primary purpose is to discover the truth behind statement
charitable vs. uncharitable
eg. I had the worst possible day ever.
charitable: Poor you!
uncharitable: You could’ve been hit by a car.
being charitable addresses the heart of the matter
being uncharitable can lead to the straw man fallacy: arguing the wrong
point, usually by taking a statement too literally
Ambiguity and Vagueness
ambiguity: having two or more different but possibly precise meanings
avoid unless it serves a clear literary purpose
vagueness: lacking a precise meaning, unclear what it would take for
statement to be satisfied
eg. Your total comes to about $50.
sometimes necessary to convey a vague idea
eg. Lots of people own televisions.
pointless to be more precise
arise from use of words within sentences, not words themselves
referential ambiguity: arises when a word or phrase can refer to two or
eg. He is a big opera star.
distributive: to say something about each and every member of the class
eg. We have a large wrestling team. -> big members
collective: to say something about the class itself
eg. We have a large wrestling team. -> many members Grammatical Ambiguity
grammatical ambiguity: structure of sentence allows for multiple
eg. I told him to call me in the morning.
Use and Mention
use-mention ambiguity: failure to distinguish between using or
mentioning a word or phrase
eg. Paddy is Irish.
the person named Paddy is of Irish descent -> use
the name “Paddy” is an Irish name -> mention
ANALYTIC, CONTRADICTORY AND SYNTHETIC STATEMENTS
statements whose truth or falsity is determined by their meaning
analytic: statement that is true by definition
eg. Bachelors are unmarried men.
Triangles have three sides.
contradictory: statement that is false by definition
synthetic: whose truth can only be determined by relying on observation
a non-analytic, non-contradictory statement
NECESSARY AND SUFFICIENT CONDITIONS
antecedent condition: a condition that must be met in order for a claim to
consequent: the outcome of such a condition
necessary condition: if x condition is false then y condition is also false,
but the truth of x does not guarantee the truth of y
eg. Being at least 18 years of age is a necessary condition for being eligible
to vote in federal elections in Canada.
if you are not 18 you cannot vote, but being 18 does not guarantee you the
right to vote (electoral officers and insane persons ineligible to vote)
the author asserts that its falsity or absence guarantees that the logical
consequent won’t be true
sufficient condition: the truth or presence of x guarantees y but the falsity
or absence of x does not prevent y eg. Holding a BA from the University is a sufficient condition for being a
member of the University Alumni Association.
if you hold a BA you are a member of the UAA but even if you do not hold a
BA does not mean you are not a member of the UAA (you could hold a BSc)
author asserts that the condition is something whose truth or presence
guarantees that the logical consequent will be true
sometimes conditions are both necessary and sufficient casual conditions
eg. It is a condition for a candidate to be declared the winner of an election
that they received the most votes of this election.
sufficient: any candidate receiving the most votes must be declared the
necessary: any candidate to be declared the winner must receive the most
- listing all necessary conditions makes them jointly sufficient conditions
eg. The necessary conditions for being eligible to vote in federal elections in
being at least 18 years of age,
not being an elections officer or an insane person, and
being a Canadian citizen.
these conditions are jointly sufficient because anyone who satisfies all
three of them are eligible to vote
the listing of all sufficient conditions states the necessary condition in the
sense that at least one of x conditions must be met for y condition to be true
a necessary condition guarantees that y won’t be true unless x is true
a sufficient condition guarantees that y will be true if x is true 9/13/2013 5:41:00 PM
Wednesday Oct 3
Chapter 4 - Reconstructing Arguments
reconstructing the argument: process of determining the argument by
defining the premises, conclusion and relationship between them
must not violate author’s intent or principle of charity
- four steps:
identify all inference indicators
identify the conclusion
identify the premises
write the argument in standard form
C or MC
IC1, IC2 (intermediary conclusions)
no need to add “M” for missing intermediary conclusions
the premises can be in any order but the conclusion must come last
eg. We should focus the economy more on manufacturing. The reason is
that our wealth is only increased to the extent that we produce concrete
goods like electronics, cars, games, etc.
inference indicator: “The reason is that”
P1: Our wealth is only increased to the extent that we produce of concrete
goods like electronics, cars, games, etc.
MP2: We should do what we can to increase our wealth.
MP3: The economy is not maximally focused on manufacturing as it is.
MP4: Manufacturing is the sector that produces concrete goods like
electronics, cars, games, etc.
C: We should focus the economy more on manufacturing.
MISSING PREMISES AND CONCLUSIONS
presupposition: a statement logically required to make an argument’s
stated claim(s) true missing premise must, if true, support conclusion
missing premise should be as plausible as possible
to construct a missing conclusion, follow the same steps as for constructing
a missing premises
try to reconstruct a reasonable thought
fill in premises until argument is deductive if trying to make evidence as
clear or unclear as possible
helps clarify the point of the argument and simplifies the assessment of it to
one question: are the premises true?
premises and conclusion should be rephrased as necessary and
dependencies removed in the rest of the text
eg. “John is not outside, I’ve seen him inside.”
inference indicators: none
P1: John was seen inside the classroom.
MP2: If John was seen inside, he is inside.
MP3: If John is inside, he is not outside.
C: John is not outside.
Reports of Arguments
a statement that says so-and-so argued in a certain way
eg. John refuses to vote in elections because he believes that all politicians
states an argument but does not necessarily make one
sometimes an argument is reported in order to make it
an attempt to show why or how something happen(s/ed) when there is little
reason to doubt the truth of the conclusion
eg. My car won’t start because it is out of gas.
may look like an argument
eg. When politicians are perceived as corrupt, they tend to lose votes.
P1: Politician is perceived as corrupt
C: Politician will lose votes ... but it is also an explanation of why the politician lost votes
when we argue for a claim, we try to convince an audience that it is true
when explaining a fact, we try to show how it came to be true
causal explanation: explain an event by reference to its causes
non-causal explanation: explained in reference to function, rules, etc.
eg. we explain volleyball by explaining the rules of volleyball
THE STRUCTURE OF ARGUMENTS
tree diagram: schematic representation of the structure of an argument
using letters to represent the premises and conclusions and an arrow to
an argument with just one premise supporting its conclusion
eg. She must have walked home because her bike has a flat tire.
P: Her bike has a flat tire
C: She must have walked home.
an argument made of two or more premises that support the conclusion
eg. You should not smoke because it smells bad and it is bad for your health.
P1: Smoking smells bad.
P2: Smoking is bad for your health.
C: You should not smoke. T argument
an argument in which two or more premises work together to support the
premises provide virtually no support for the conclusion on their own
eg. If you have a meeting I’ll drive. You do have a meeting, so I’ll drive.
P1: If you have a meeting, I’ll drive.
P2: You do have a meeting.
C: I’ll drive.
How to decide between V or T
if premises alone can provide support for the conclusion, it is a V argument
ask: does P1 significantly support C even if we suppose that P2 is false?
does P2 significantly support C even if we suppose that P1 is false? if yes
and yes, then it is a V argument
sometimes premises act together and separately (both V and T diagrams) in
eg. A charismatic leader is what we need and Angela can get peoples’
attention. She is the most qualified person for the job.
P1: We need a leader who can get peoples’ attention.
P2: Angela can get peoples’ attention.
P3: Angela is the most qualified person for the job.
MC: Angela should get the job as a leader.
contains more than one arrow as it contains sub-conclusions ask: C1, therefore C2? or C2, therefore C1?
when sub-conclusions exist, it is used as both a conclusion and a premise
watch out for when people are merely stating an opinion rather than an
eg. The liquid leaking from your car is water. There are only three liquids in
the engine: water, oil, and gasoline. The liquid that is leaking is not oil
because it is not viscous, and it is not gasoline because it has no odor.
MP1: A liquid is leaking from your car engine.
P1: There are only three liquids in the engine: water, oil, and
IC1: The liquid that is leaking is not oil.
P2: The liquid that is leaking is not viscous.
MP2: Oil is viscous.
IC2: The liquid that is leaking is not gasoline.
P3: The liquid that is leaking has no odor.
MP3: Gasoline has an odor.
C: The liquid that is leaking from your car engine is water. 9/13/2013 5:41:00 PM
Chapter 5 - Assessing Arguments
a sound argument: true premises and logical strength
premises must be:
concerns each premise considered on its own
the premises must be acceptable as premises for the argument
not just a matter of being true (contrary to Hughes & Lavery)
eg. If such actions were not illegal, the would not be prohibited by the law
P1: If actions x were not illegal, they would not be prohibited by the law
MP1: Actions x are prohibited
MC: Actions x are illegal
the fallacy of begging the question: a premise of an argument begs the
question when it is no more acceptable to the intended audience of the
argument than the conclusion of the argument (differs from H&L p. 116-
definition too broad)
MP1 begs the question in that it would not be acceptable to anyone that
needs convincing of the conclusion (it is a rewording of conclusion)
a premise P can be true but not acceptable as part of a given argument
concerns the relationship between each individual premise, considered on its
own, and the rest of the argument
premises are relevant when they provide some support for the conclusion
concerns the relationship between all premises considered collectively and
premises are adequate when they provide sufficient support for the
conclusion to warrant it
adequacy implies relevance, so adequacy is what really matters ASSESSING ARGUMENTS
Identify the main conclusion
what is the author driving at?
Identify the premises
what reasons do the author provide as support for the conclusion?
Identify the structure of the argument
Check the acceptability of the premises
if counterfactual argument, the premises will not be true
Check the relevance of the premises
must be considered in context of argument
Check the adequacy of the premises
notice the degree of support
Look for counter-arguments
The Role of Fallacies
H&L speak of two approaches to assessing arguments: the criterial approach
and the fallacies approach
fallacies don’t really provide a method of assessment, they are just common
errors made in an argument: flaws that typically make premises
unacceptable or inadequate
still useful to be aware of common fallacies in order to detect and avoid
fallacy of affirming the consequent: results in premises that don’t adequately
support the conclusion
the premises can be true while the conclusion is false
lacks logical strength
If p, then q.
Therefore p. 9/13/2013 5:41:00 PM
Ch 6 - Assessing Acceptability
assesses the individual premises on their own
how we go about assessing a claim depends on what kind of claim it is
EMPIRICAL VS. NON-EMPIRICAL
empirical: a claim that can be verified or falsified through observation or
eg. My car won’t start.
no general rule to assess premises
how well defended a premise must be to be acceptable depends on context
sometimes we want proof: a defense that shows that the premise is true
eg. publication of scientific results, conviction for murder
sometimes proof is an unreasonable standard
“It is common knowledge that…” - careful!
check whether satisfactory empirical evidence has been provided
written ≠ true
universal claims are hard to prove
one counterexample is enough to refute the claim
vague statistical claims are hard to assess
eg. Most students wear purple. -> how many is most?
non-empirical: cannot be verified or falsified by empirical evidence
analytic and contradictory statements are non-empirical
eg. The government should provide free health care.
moral claims (the way the world is does not dictate the way things ought to
eg. No one should ever lie. You ought to donate to Oxfam.
aesthetic claims (what’s good in a non-moral sense)
eg. Heavy metal is better than rap. Domino’s is better than Pizza Pizza.
mathematically provable, analytic, and contradictory claims
eg. Bachelors are unmarried.
moral and aesthetic claims can be defended by using one of two methods: by appealing to general moral or aesthetic principles
by spelling out facts about which a moral or aesthetic judgment is required
in more detail
universalization maxim: if an action is such that everyone doing it is
impossible or obviously undesirable, then it is a bad action (Kant)
eg. There are no barriers preventing free riders at suburban train stations in
Sydney. Is it wrong to free-ride?
obviously undesirable if everyone does it
utilitarian maxim: one should maximize the greatest good for the greatest
when you choose between different courses of action, choose the one that
maximizes the total happiness in the world
eg. You ought to donate to Oxfam in order to alleviate poverty in the world.
particular statement: a statement about specific people or objects
eg. Alice the butterfly entered my house yesterday.
existential statement: a generic statement to the effect that something
meets a certain condition
key words: some, someone, somebody, there is, at least...
eg. Some butterfly entered my house yesterday. There is at least one
student with a red sweater in this class.
universal statement: a statement to the effect that all members of a class
satisfy a condition
key words: all, every
eg. Every butterfly entered my house yesterday. All Western students wear
statistical statement: a statement to the effect that a certain proportion of
members of a class satisfy a condition
eg. 50% of all butterflies entered my house yesterday. Most Western
students wear purple.
every simple statement will be either empirical or non-empirical, and will
have either particular, existential, universal, or statistical strength
eg. All swans are beautiful. (universal non empirical)
eg. Bob ought to apologize. (particular non-empirical) eg. No one called the office. (universal empirical)
eg. A car is parked wrongly. (existential empirical— if “wrongly” means
against the law)
eg. Pizza with BBQ sauce is usually too sweet. (statistical non-empirical)
eg. There is a good solution to the problem. (existential non-empirical,
depending on definition of “good”)
eg. Most students live near campus. (statistical empirical)
complex cases exist that fall in more than one category at once
eg. It is wrong that there is one subject that Alice fails most of the time.
(part empirical, part non-empirical, at once particular, existential, universal,
begging the question: premises are circular to the conclusion, anyone who
does not already believe in the conclusion would not be compelled to believe
it by its premises
inconsistency: not all premises can be true
such arguments can be used to prove anything
equivocation: when a premise is open to two interpretations and the
interpretation that is unacceptable is required by the conclusion
eg. Drug dependency is a serious problem in our society. Just look how
many people can’t function without coffee.
the implicit that coffee is a drug is only true in a weak “drug” that does not
support the conclusion
one of the most common fallacies
false dichotomy: a premise that presents options as exhaustive, exclusive,
or both when they are not
exhaustive options: cover all the possibilities
eg. Alice is either pregnant or she is not.
non-exhaustive: more than two possibilities
eg. Bob is either young or he is old.
exclusive options: cover possibilities that cannot be combined
eg. It’s either the AM or PM.
non-exclusive options: possibilities can be combined
eg. being a faculty member or a student
one of the most common fallacies 9/13/2013 5:41:00 PM
Ch 7 - Assessing Relevance
assesses the relationship between each individual premise on its own and
the rest of the argument
relevance: premises prove some support for its conclusion
general test: do premises make the conclusion more likely to be true?
use judgment, non-empirical
FALLACIES OF RELEVANCE
ad hominem (“to the man”): making a negative claim about a person in
order to disprove a statement, when such claim is irrelevant to the
commonly occurs as a counterargument
to check: if someone else had made this claim, would the counterargument
be an appropriate one?
abusive: attempt to discredit a claim by making an attack on irrelevant
aspects of the person making the claim
eg. “Yeah, but you’re a greedy jerk.”
circumstantial: attempt to discredit a claim by pointing out irrelevant
features of the person’s circumstances (typically, features that make it more
likely that the person will want the claim accepted)
eg. “Yeah, but you work for the chocolate company.”
tu quoque (“you also”): when A rejects B’s claim on the grounds that the
claim is inconsistent with B’s actions or what they said
eg. “Yeah, but you ate candy earlier.”
guilt by association: involves a faulty analogy which is so transparently
faulty that the purpose of drawing this analogy is defeated in a formal
eg. “Yeah, but the Nazis thought chocolate was better too.”
appeal to pity: attempt to persuade by seeking pity
eg. “You should give me a good mark, I worked so hard on it.”
appeal to force: attempt to persuade by threat
eg. “You should give me a good mark or I’ll kill you.”
appeal to authority: attempt to persuade by saying it is the opinion of an
authority figure when the person is not an authority on the subject
eg. “You should give me a good mark because Obama would.” appropriate to appeal to authority when they are entitled to their status
eg. “I believe there are electrons because physicists say so.”
appeal to popularity: attempt to persuade by saying it is the popular
usually relevant but not adequate to establish the conclusion
eg. “You should give me a good mark, everyone else thinks so too.”
straw man fallacy: when someone makes the position they are arguing
against seem worse than it is in order to refute it
often arises from lack of charity
eg. “What I object to the most about people who oppose capital punishment
is that they believe that the lives of convicted murderers are more important
than the lives of the policemen and prison guards who protect us.” 9/13/2013 5:41:00 PM
Ch 8 - Assessing Adequacy
assesses the relationship between all premises considered collectively and
the premises of an argument are adequate when they provide sufficient
support for the conclusion to warrant it
we ought to accept the conclusion if we believe the premises
it is possible to have a false conclusion with adequate premises
mostly about logical strength— maximum logical strength = premises will
always be adequate
premises can be made adequate to establish its conclusion by weakening the
eg. Original: P1: There are dark clouds in the sky. C: It’s going to rain.
Revised: P1: There are dark clouds in the sky. C: There is a
chance it will rain.
Use general principles of deduction and induction.
Use your judgment regarding degree of support the premises have for the
Watch out for common fallacies.