Philosophy 203
Dr. C. Klatt
Assignment #4
Use truth trees to test the following:
1. Consistency
~[(S > V) & (V > ~S)]
(W = Z) > (S = V)
~(W = ~Z)
2. Equivalence
A > (~B > ~A) and B v (~A > A)
3. Tautology, Contradiction or Contingent Form
[(P > Q) & (R >

Practice Assg 4 Truth Trees
Use a propositional truth tree to determine the follow:
1) Are these sentences a tautology, contradiction or contingent?
a) (G > (N > ~G) & (N = G) & (N v G)
b) [(G & N) > H) & (G > H) > P)] > (N > P)
2) Are the following sente

Philosophy 203: Elementary Symbolic Logic
Instructor: Dr. C. Klatt
Practice Test #1
Section I: Short Answer [15 marks]
a) If A is true, X is false, and the truth value of S
is unknown, what is the truth value of the
following statement?
(A & S) = (X v S)

PHILOSOPHY 203: Symbolic Logic
Instructor:
Dr. Carrie Klatt
Email:
cklatt@uvic.ca
Text:
Essentials of Symbolic Logic by R. L. Simpson
Definitions
In propositional logic we deal with combinations of sentences or propositions.
Joe is handsome is a sentence.

Copyright 1999, 2000, 2002, 2003, 2007, 2008, 2011
CSLI Publications
Center for the Study of Language and Information
Leland Stanford Junior University
First Edition 1999
Second Edition 2011
Printed in the United States
19 18 17 16 15
4e 5 6 7
Library of

Phil 203
Week Two
Counterexamples
Well talk soon about ways of showing that an argument is valid.
To show that an argument is invalid, you can give a counterexample.
This is a situation in which the premises of the argument are true and the conclusion

Phil 203
Week Three
Other Translations
a is neither small nor large.
(Small(a) Large(a)
Small(a) Large(a).
d is not both a tetrahedron and large.
(Tet(d) Large(d)
Tet(d) Large(d).
The pairs of sentences given for each phrase are equivalent.
What t

Phil 203
Week One
Administrative Basics
Instructor: Dr. Audrey Yap (ayap@uvic.ca)
Office: CLE B307
Office Hours: Thursdays: 10:00-12:00, and by appointment in CLE B307
Email is the best way to get in touch with me!
The course website is run through Cou

Phil 203: Elementary Formal Logic
Syllabus
Instructor: Dr. Audrey Yap (ayap@uvic.ca)
Office/Phone: CLE B307 (721-7510)
Office Hours: Thursdays: 10:00-12:00, and by appointment
Class Information: TWF 11:30-12:20 in ELL 167
Course Website: Through CourseSpa

Phil 203: Elementary Formal Logic
Syllabus
Instructor: Dr. Audrey Yap (ayap@uvic.ca)
Office/Phone: CLE B307 (721-7510)
Office Hours: Thursdays: 10:00-12:00, and by appointment
Class Information: TWF 11:30-12:20 in ELL 167
Course Website: Through CourseSpa

Truth Tables
p
T
T
F
F
q
T
F
T
F
~p
pq
p &q
p>q
p= q
What is the truth value of ~(C D) > (D = E) when C, E are false and D is
true?
~(C D) > (D = E)
C
D
E
CD
~(CD)
D=E
~(CD)>(D=E)
C
T
T
T
T
F
F
F
F
D
T
T
F
F
T
T
F
F
E
T
F
T
F
T
F
T
F
~(C D) > (D = E)
K
M

Truth Trees
Truth trees provide a practical way for us to determine consistency, validity,
and equivalence when the number of atomic sentences is large.
When forming truth trees we will follow two guidelines.
1) Always write true statements.
2) Branching

The Operators
A, B, C, . A1, A2.
.
Negation:
, . p, q .
~A
It is not the case that A.
Conjunction:
(A & B)
Disjunction:
(A B)
A or B.
Conditional:
(A > B)
If A then B.
Bi-conditional:
A and B.
(A B)
(A = B)
A if and only if B.
WFF= well-formed formula
Maj