2. Types of Reasoning
Inductive reasoning- • By example
• By cause
creates generalization • By sign
about people, events, • By comparison
and things. • By authority
Deductive reasoning – • A major premise
how we apply • A minor premise
• A conclusion
generalization
•Fallacy of false dilemma
•Fallacy of appeal to emotion
•Fallacy of non sequitur
•Fallacy of the slippery slope
•Fallacy of ad hominem
Fallacy- an error in •Fallacy of hasty generalization
•Fallacy of circular reasoning
reasoning •Fallacy or appeal to ignorance
•Bandwagon fallacy
•Post hoc ergo propter hoc fallacy
•Fallacy of appeal to pity
•Straw-Man fallacy
3. Example reasoning -involves using specific instances as
a basis for making a valid conclusion.
Tests for reasoning by example
There must be
sufficient # of
The examples
examples to
must be typical
justify the
of the whole
generalized
conclusion
Important The examples
counter must be
examples must relevant to the
be accounted time period of
for your argument
4. Sign reasoning-involves inferring a connection between two
related things, so that the presence or absence of one indicates
the presence or absence of the other.
Other substance/attribute Cumulative sign reasoning
relationships must be considered. produces a more probable
connection.
5. Comparison reasoning- is also known as reasoning by analogy. Involves
drawing comparisons between two similar things, and concluding that
• Figurative comparisons: • Literal comparisons:
- attempt to link - attempt to establish a
similarities between link between similar
two cases from classifications; people
different classifications - to people, cars to cars,
- carry no weight in states to states.
terms of providing
logical proof for an
argument.
The more towards the figurative side the comparison is , the less the argument is logically valid.
The more towards the literal side the comparison is, the more logically valid it is.
6. 1. To be considered as proof, the analogy must
be a literal one.
2. The cases need to contain significant points
of similarity.
3. Cumulative comparison reasoning will
produce a more probable conclusion.
7. Reasoning from authority is used when a person
argues that a particular claim is justified because it is
held or advocated by a credible source. This argument
can be used in two ways:
First, an argument can be Second, an argument can
accepted simply because be supported with the
someone you consider an credibility of another
authority advocates it. person.
8. The authority must be credible.
Views of counter authorities must be taken into account.
Cumulative views of authorities increase the validity of
the reasoning.
9. Deductive Reasoning
• The major premise- is a general statement.
Ex. All telemarketers are obnoxious.
• The minor premise – is a statement of a
specific instance related to the major premise.
Ex. The person on the phone is a telemarketer.
• The conclusion – is a statement derived from
the minor premises relationship to the major
premise.
Ex. The person on the phone is obnoxious.
10. 1. Fallacy of the false dilemma- occurs when an
argument offers a false range of choices and
requires that you pick one of them.
2. Fallacy of appeal to emotion- when someone
manipulates peoples’ emotions in order to
get them to accept a claim as being true.
3. Fallacy of non-sequitur- is used when a
statement openly contradicts itself and
makes no sense.
11. 4. Fallacy of the slippery slope – reduces an
argument to absurdity by extending it
beyond its reasonable limits.
5. Fallacy of ad hominem –consists of saying
that someone’s argument is wrong purely
because of something about the person
rather than about the argument itself.
6. Fallacy of hasty generalization – occurs when
an arguer bases a conclusion on too few
examples that are not necessarily typical of
the conclusion being made.
12. 7. Fallacy of circular reasoning – a repeated
assertion of a conclusion without giving
reasons in its support.
8. Fallacy of appeal to ignorance - occurs by
trying to make an argument in a contest in
which the burden of proof falls on the arguer
to show that his or her position is actually
true, not just that it has not yet been shown
false.
9. Bandwagon fallacy – refers to join a cause
because of its popularity.
13. 10. Post hoc ergo propter hoc fallacy – is based
upon the mistaken notion that simply because
one thing happens after another , the first
event was a cause of the second event.
11. Fallacy of appeal to pity – the arguer tries to
get people to agree with their conclusion by
evoking pity and sympathy either with their
situation or with the situation of some third
party.
12. Straw – Man fallacy – the arguer attacks on
argument which is different from, and usually
weaker than, the opposition’s best argument.
14. PERSUASION: THEORY AND PRACTICE
By Kenneth Anderson
“Logical appeals are powerful forces in persuasion.
However, logic alone is rarely sufficient to yield
persuasion. Desires and needs of receivers affect and
determine what they will accept as logical demonstration.
Thus, it is possible for one person to report that he or she
is convinced by the logic used while another person remains
horrified at the lack of logic presented.”
