Note: We have scheduled in-class quiz #3 for next Wednesday (November 20). It will consist of 5 proofs lifted directly from Van Cleave, exercise #21.
Logic & Critical Reasoning
Friday, November 15, 2024
Wednesday, November 6, 2024
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.
Monday, October 21, 2024
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")
Monday, October 7, 2024
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
p∨q,
~q
∴
p
Simplication (Simp)
p.q
∴
p
p.q
∴
q
Conjunction (Conj)
p,
q
∴
p.q
Hypothetical Syllogism (HS)
p⊃q,
q⊃r
∴
p⊃r
Addition(Add)
∴
p∨q
Constructive Dilemma (CD)
(p⊃q),
(r⊃s),
p∨r
∴
q∨s
Friday, September 27, 2024
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.
Wednesday, September 25, 2024
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.