Tuesday, October 27, 2026

Sample quiz #2

Practice Quiz #2         

Note: Quiz #2 is scheduled for Monday, 11/2 (11 am class), and Wednesday 11/4 (10 am class)                                                     

1. True or False: One can deduce P from the disjunct P or Q.

2. True or false: The conclusions of all valid deductions are true statements.

 

3. Write an invalid argument.

 

4. Write an uncogent argument.

 

5. True or false: The antecedent of a conditional claim is a necessary condition for the consequent.

6. Reproduce the chart for induction and deduction.

 

 

 

7.  Does the following argument violate the is-ought gap?

Many animals eat other animals. Humans are animals. Therefore, there is nothing wrong with humans eating other animals.

8. Translate into formal symbolic language:

a.      You cannot both enjoy the class and not attend. (use E and A)

 

b.       Although this quiz is cumulative, you will do well if you study. (use C, W, and S)

 

c.       If you study or are a genius, you will ace the quiz. (use S, G, and A)


9. What is "modus ponens"?


10. Is the following argument valid?

If Joe is a dog, then Joe is a mammal.

Joe is not a dog.

Therefore, Joe is not a mammal.


Friday, October 23, 2026

Assignment #5: Formal Proofs

Read: Van Cleave, section 2.11. Do exercise sets 16 & 17.

8 Rules of valid inference:

Modus Ponens (MP)

p⊃q,
p
∴
q

 Modus Tollens (MT)

 p⊃q,
~q
∴
~p

 Disjunctive Syllogism (DS)

p∨q,
~p
∴
q

 or, if desired,

p∨q,
~q
∴
p

Simplication (Simp)

p.q
∴
p

 or, if desired,

p.q
∴
q

Conjunction (Conj)

p,
q
∴
p.q

Hypothetical Syllogism (HS)

p⊃q,
q
⊃r
∴
p
⊃r

Addition(Add)

 p

∴
p
∨q

 Constructive Dilemma (CD)

(p⊃q),
(r
⊃s),
p
∨r
∴
q
∨s

 

 


Friday, September 25, 2026

Sample Quiz #1

 Quiz #1; 10 am section


1. Is the following a statement?

“Please help yourself to more tofu.”

2. Define statement, premise, and conclusion.

3. List 2 premise indicators and 2 conclusion indicators. 

4. What is the difference between an explanation and an argument?

5. Is the following argument valid?  Why or why not?

“All dogs are reptiles; Fido is a reptile; Therefore, Fido is a dog.”

6. Reproduce the chart that depicts the nature induction and deduction.

7. Why is the “is-ought” gap an issue in logic?

8. Give an example of an enthymeme and then supply the missing premise.

9. Produce a truth table for conjunction.

10. True or false: logic is the study of empirical observation.

Monday, September 14, 2026

Friday, September 11, 2026

Assignment #2 The nature of an argument

Things to do:

2. Read Van Cleave, 1.1-1.2.  In your notebook dedicated to this class, do all of the exercises.  Bring questions/comments to class.


Friday, August 28, 2026

Assignment #1: Handout CPE, syllabus, defininitions

Welcome to Logic and Critical Thinking. 

Things to do:


1. Research the term "philosophy" and the phrase "critical thinking."  Find definitions that strike you as inclusive and instructive and bring them to class in a dedicated (section of a) notebook.

2. Review carefully Handout CPE and the syllabus; raise any questions about these documents in our next class.