Assignment #8: Informal Fallacies

 1. Read: Knachel (a new text for us) "chapter 2" (informal logical fallacies):

https://open.umn.edu/opentextbooks/textbooks/fundamental-methods-of-logic

Do the exercises at the close of the chapter.

Assignment #7: Categorical Logic; Quiz #2

1. Read Van Cleave, section 2.14; do exercise set 18.

2. Read 2.17; do exercise set 21.

Reminder: we will have quiz #2 on Monday the 28th.

Supplemental: Here's a nice video explanation of deductive proofs (note; the video employs ^ for "and")

Bing Videos

Assignment #6: Formal Proofs

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

8 Rules of valid inference (I'll have a handout next class):

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

 

 

Assignment #5: "not both" "neither nor" and conditionals

Read and do exercises for Van Cleave, 2.5 & 2.7

Reminder: Quiz #1, Friday, October 4.

Sample Quiz #1

Sample Quiz #1

1. What is a logical argument?

2. List 2 premise indicator words and 2 conclusion indicator words.

3. Which of the following is an argument:

a. “All dogs are reptiles; Fido is a dog; therefore, Fido is a reptile.” B. “Go to your room, because you have been bad, and all bad persons must go to their rooms.”  C. “Water freezes at 32 degrees because the molecules get so cold that they slow down enough to hook onto each other, forming a solid crystal.”

4. What makes an argument invalid?

5. True or false?  “A sound deduction may have one false premise.”

6. Reproduce the chart for induction and deduction. 

7. Compose an enthymeme, then supply the missing premise.

8. Translate into formal symbolic language:

“It is Friday and it is not raining.”

9. Write an argument that attempts to leap over the “is-ought gap.”  What missing premise would make it valid?

10. Reproduce the truth table for negation.

 

Assignment #4: Formal Methods I

 Read and do exercises, Van Cleave, 2.1-2.4

Assignment #3: Validity, Soundness, Strength, Enthymemes

Begin reading and reviewing the exercises in Van Cleave, 1.3; and 1.6-1.9