Assignment #9: Writing fallacies

I. Compose fallacies as described in each question:

1 An appeal to the people (ad populum) on the subject of Thanksgiving

2. A complex question involving on the subject of driving a car

3. A false cause fallacy on the subject of snow

4. A hasty generalization on the subject of dogs

5. A false dichotomy on the subject of eye-color

6. An equivocation on the subject of money

7. An amphiboly on the subject of skyscrapers

8. A division fallacy on the subject of tools

9. An accident on the subject of morality

10. An appeal to ignorance on the subject of religion

II. Quiz #4: Wednesday, 12/10.  Content: Informal fallacies only.

Quiz #3: extra credit

Rewrite the following argument in standard categorical propositional form and test for validity using a Venn diagram.

Turkeys are sentient beings. No sentient being should be on the Thanksgiving menu. Therefore, turkeys should not be on the Thanksgiving menu.

Assignment #8: Informal Fallacies

1. Begin reading: Hurley, "Informal Fallacies":

Informal fallacies

Extra Credit; Quiz #2

Translate and show validity using the 8 rules of deductive reasoning:

If you care about your education, you will succeed; and if you succeed, your years at MCLA will be spent wisely. You do care about your education, and you will either fail to spend your years at MCLA wisely or you will reap one of life's greatest rewards. It follows that you will reap that reward. (C, S, Y, R)

Assignment #7: Formal Methods II: Categorical Logic

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

2. Read 2.17; do exercise set 21.

Reminder: Quiz #2, next Monday, November 3.  The quiz will consist of 5 problems lifted from exercise 17 in Van Cleave.

Assignment #6: Formal Proofs

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

(Also complete the 6 translations + proofs handed out on Friday.)

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

 

 

Sample Quiz #1

Sample Quiz #1

1. What is a logical argument?

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

3. Distinguish arguments from explanations among the following:

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 are the possible ways an argument can be unsound?

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:

a. It is Friday and it is not raining. (use F and R)

b. My name is not Bob or Sally. (use B and S)

c. Next week, we will meet on Monday or Wednesday, but not Tuesday or Thursday. (use M, W, T, R)

d. I'll have some cake or ice cream, but not both. (use C and I)

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 "and".