 Arguments are considered rational when they
correspond with accepted standards of reasoning.
 Reasoning
 “The power of comprehending, inferring, or thinking in
orderly rational ways.”
 Reasoning involves 3 steps
 Identify data/grounds used to develop claim
 Reason from data through logical induction or deduction
 Offer claim or conclusion that builds upon the data and
constitutes a new and original insight
 Focus of this chapter will be on step 2
 Inductive-arguing from specific to general conclusion
 Deductive-moving from general instances to specific
conclusions
 When you have knowledge or info about specific cases
but lack understanding of factors that may unite these
cases into general conclusion
 Moving from specific evidence to general conclusion
 3 types of inductive arguments
 Arguments by Example
 Arguments by Analogy
 Arguments from Causal Correlation
 Argument by Example
 Arguing on basis of examples
 Using examples from known cases to draw
conclusions about unknown cases
 Ex. Bill, Diane, and Lynn were communication majors
and they got into really good law schools (specific
examples). Communication must be a good pre-law
major (general conclusion).
 Ex. Last time I tried to get help from advising office, I
got passed around from person to person. No one knew
the answers to my questions. That dept. is incompetent
 Testing arguments by example - things to consider
 1. Are there enough examples offered to support claim
 Ex. If Bill, Dianne, and Lynn were only 3 comm. majors then
argument is no longer strong-overgeneralization
 2. Are examples cited typical of the category or class that
the arguer is trying to generalize to?
 Ex. Because Advising Office couldn’t answer 1 person’s
questions doesn’t mean they are incompetent. Maybe
questions were rare or not relevant to their dept.
 3. Are negative examples of rival stories sufficiently
accounted for in argument
 Ex. Were there other comm. Majors who didn’t get into law
school?
 4. Are cited examples relevant to the claim being
advanced
 Fallacy-a flaw in the reasoning process
 Hasty Generalization-type of fallacy
 Arguments from examples that move too
quickly or without sufficient rationale
 Arguments by Analogy
 Seeks to identify similarities between cases that might
seem dissimilar, in order to allow conclusion to be
made-building argument by comparing
 Literal Analogy
 Drawing direct comparison btwn. 2 or more cases
 Ex. Students who want education only to prepare for
careers are like apprentices attaching themselves to
carpenters
 Figurative Analogy
 Makes comparisons btwn. classes that are dissimilar but
have common characteristics
 Ex. The builders and developers have attached the
underdeveloped hillsides of the city like hungry locusts
 Arguments from Causal Correlation
 Examines specific cases and identifies a
relationship or correlation
 Ex. Excessive exposure to violence on television or
in video games leads to a willingness to accept
violence as appropriate behavior and decreases
people’s sense of revulsion toward violence in real
life.
 Testing Causal Correlations-things to consider
1. Consistency of correlation
 Is there true correlation or just chance
2. Is the correlation a strong one?
 Requires looking at all the data
 Looking at context and other factors
3. Does cause effect pattern follow predictable time
sequence?
 How long does it take to see the effect after cause…and is
effect truly coming from that cause.
 Ex. Children exposed to lead suffer learning disablities
 Does it take hours, weeks, months for symptoms to surface?
 Generalizing from theories or principles believed to be
true to claims about individual cases.
 Moving from general evidence to specific claims
 2 types of deductive arguments
 1. Arguments from Sign
 2. Arguments from Causal Generalization
 Arguments from Sign
 Relies on presence of certain attributes seen in
specific case to prove that it can be related to a
generalization that is assumed to be true
 Ex. Bob is suffering from fever, sore throat, fatigue,
headache, muscle weakness, and night sweats. He
might have contracted mononucleosis
 People who usually suffer from this symptoms have mono.
 Testing Arguments from Sign-things to consider
 1. Are the cited signs always indication of general
conclusion?
 Ex. The symptoms mentioned may also be symptoms for other
medical issues
 2. Are there enough signs present to support conclusion
offered?
 Ex. If Bob only had fever and sore throat, that may not be
enough to conclude mono.
 3. Are contradictory signs present and have they been
carefully considered?
 Ex. Bob is gaining weight along with his other symptoms
which is unusual for mono…need to account for weight gain.
 False reasoning by sign
 Moving too quickly from limited number of signs
 Guilty by association
 Ex. Attacking a person because of people he is friendly
with
 Arguments from Causal Generalization
 Argues from general principles that are assumed to
be true to judgments about specific cases under
consideration
 Ex. Steven is bound to abuse his children because he
was himself abused as a child
 Ex. It is unwise to raise interest rates. Every time rates
have been raised, a recession has followed
 Testing Causal Generalization Arguments 1. Is cause sufficient to produce effect
 Ex. Steven’s abuse may impact his parenting style but many
people have been abused and are still good parents
 2. May the cause result in other effects
 Ex. Steven’s abuse may actually motivate him to be better
parent
 3. May intervening factors preclude expected
relationship between cause and effect
 Ex. Higher interest rates may actually stabilize and
strengthen economy
 False Reasoning by Causal Generalization
 Making a false generalization
Deductive arguments can be tested by phrasing them
in syllogistic form and examining structural
properties…


Syllogism-a formal, logical type of reasoning
Consists of
1. a major premise (general case)
2. a minor premise or (specific case), and
3. a conclusion.
Ex. Major Premise: All men are mortal
Minor Premise: Socrates is a man
Conclusion: Therefore Socrates is a mortal
Ex.Major Premise: All Christians believe in God
Minor Premise: Fred is a Christian
Conclusion: Fred believes in God
 These are examples of categorical syllogism-one
that makes a statement about all cases within
the given category
 Absolute statement
 If then syllogism
 Major Premise: If students study they get better grades
 Minor Premise: The students will study
 Conclusion: The students will get better grades
 Either or statements
 Major Premise: The University must either raise tuition
or cut faculty and programs
 Minor Premise: The University is unwilling to make
cuts
 Conclusion: Therefore tuition must be increased
 Used to understand the components of argument and
provides insight into reasoning process
 1. Claim-proposition
 2. Grounds-support or basis for claim
 3. Warrant-connection between grounds and claim
 4. Backing-support for warrant
 5. Modality-degree of certainty for claim
 6. Rebuttal-exceptions that might be offered to claim