9/23/10 Fallacies of Logical Structure I. Fallacies of Logical Structure Kelley says that these fallacies involve subtle logical errors with the argument itself. Dont all of the fallacies involve subt
1
This paper identifies all of the fallacies that you need to know
for the course. (There are hundreds of other fallacies.)
Quiz and PostTest Questions
Quiz and test questions will present you with li
PL 111 FOUNDATIONS OF LOGICAL REASONING
DR. R. E. FITZGIBBONS
BRIDGEWATER STATE COLLEGE
SPRING 2009
LOGIC
What logic is
As an academic discipline, logic studies the criteria for differentiating sound
Todays Topics (9/28)
I.
Two Ways that a Conclusion can Follow From a Set of Premises
II.
Valid Arguments
a)
A Test for Validity Validity and Form Invalid Arguments Valid vs. Invalid Arguments
b)
III.
Todays Topics (10/26)
I. II. III. IV. V. VI. VII.
Truth-Values Truth-Functional Connectives The Truth-Table for Conjunctions The Truth-Table for Negations The Truth-Table for Disjunctions The Truth-Ta
Todays Topics (11/2)
I. II. III. IV.
Argument Forms Logical Relations Using Truth-Tables to Test for Validity Validity and Form
3/4/11
I. Argument Forms
Like a propositional form, an argument form rep
Todays Topics (9/16)
I. II.
a.
What is a fallacy? Subjectivist Fallacies
Subjectivism Appeal to majority Appeal to emotion Appeal to force
b.
c.
d.
3/4/11
I. What is a fallacy?
Defined broadly, a fall
Todays Topics (12/2)
I.
Immediate Inferences
a. b. c. d. e. f. g.
Taking the Converse Conversion The Complement of a Class Taking the Obverse Obversion Taking the Contrapositive Contraposition Contrad
Todays Topics (12/2)
I.
Immediate Inferences
a. b. c. d. e. f. g.
Taking the Converse Conversion The Complement of a Class Taking the Obverse Obversion Taking the Contrapositive Contraposition Contrad
Todays Topics (10/5)
I. II. III.
Review of Validity Soundness The Conclusion of a Sound Argument is True
3/4/11
I. Review of Validity
When evaluating arguments, we should ask: a. Are the premises true
Todays Topics 10/21
I.
Review
a) b)
Connectives Compound, Component, and Simple Propositions The Main Connective The Symbols of Propositional Logic Identifying Propositional Forms
c) d) e)
II.
Negatio
Todays Topics (11/18)
I. II. III. IV. V. VI.
Necessary Conditions Sufficient Conditions Necessary and Sufficient Conditions Symbolizing Sufficient Conditions Symbolizing Necessary Conditions Symbolizi
Todays Topics (11/9)
I.
a.
Two Common Valid Argument Forms
Modus Ponens Modus Tollens
b.
II. III.
A Point about Validity Some Other Rules of Inference
3/4/11
II. Two Common Valid Argument Forms
Modus
Todays Topics (9/30)
I. II. III.
Review Logically True Propositions Validity and Logically True conclusions Logically Inconsistent Propositions Validity and Logically Inconsistent Premises
IV. V.
3/4/
3/4/11
Topics for Today (11-30)
I. II.
Categorical Syllogisms Using Venn Diagrams to Test for Validity
3/4/11
I. Categorical Syllogisms Examples
1. All whales are mammals. 2. All mammals are animals w
T opics of the Day
I.
Why study logic? What is logic?
a)
II.
What is an argument What is a good argument When do premises provide evidential support?
b)
c)
III.
a)
W hat logic is not
Logic is not psyc
Modus Ponens etc.
Modus Ponens
Modus Tollens
Affirming the Antecedent
Denying the Consequent
The Fallacy of Denying the Antecedent
The Fallacy of Affirming the Consequent
An if, then proposition is co
TRUTH FUNCTIONAL LOGIC
The new (revised by the Department of Philosophy as of Spring 2012) learning objectives for
PHIL 111 The Foundations of Logical Reasoning are less ambitions with regard to truth
Common Premise Indicators
These are premise indicators insofar as they precede one or more premises (reasons).
as indicated by
as shown by
as
because
clearly
follows from
for the reason(s) that
for
gi
1
Categorical Syllogisms and Venn Diagrams
A categorical syllogism is an argument that
1. is comprised of exactly three categorical propositionstwo premises and one conclusion;
2. contains exactly thr
Some Definitions Relative to Categorical Propositions
Contradiction
With regard to categorical propositions, propositions of the form All S is P and Some S is
not P are contradictories and proposition
Categorical Propositions: Definitions and Venn Diagrams
Categorical proposition
A proposition is a categorical proposition if and only if it has one of the following forms:
All S is P
No S is P
Some S
IfThen Translations
Below are some very common ifthen translations. These should be memorized so that
you can easily move from the ifthen formulation to each translation and then from each
translation
1
Simple IfThen Reasoning
I.
Introduction
An ifthen proposition is comprised (made up) of two distinct parts: (1) the if-clause
and (2) the then-clause.
The if-clause is the proposition that comes imm
Todays Topics (11/4)
I.
Logically Equivalent Propositional Forms Logically Equivalent Propositions Two Rules of Equivalence
a.
II. III.
Double Negation Contraposition
b.
IV.
Equivalence and Validity
3
Todays Topics (10/19)
I. II.
Introducing Propositional Logic One way of Identifying the Form of Propositions Propositional Connectives Compound, Component, and Simple Propositions A Second Way of Iden
Todays Topics (12/7)
I. II. III. Deductive vs. Inductive Arguments Proof Evaluating Inductive Arguments Strength and Weakness IV. Ar guments fr om Sample V. Some Criteria for Determining the Strength