Chapter 7: Deductive Reasoning

Question 1

valid argument

Answer 1

• one where the conclusion is the only possible conclusion given the premises

Question 2

sound argument

Answer 2

• valid & premise are known to be true
• it is possible to have a valid argument that is not sound
• if there is contrary evidence, the argument may still be valid but it is not a sound deduction

Question 3

Mary Henle study

Answer 3

• Ps were presented syllogisms that appeared in form of basic narrative & asked about conclusions
• Ps had to verify is conclusion was valid & asked how they got to this answer
• Ps failed to reason logically = failed to distinguish between conclusion that was logically valid & one that was factually correct
• failed to accept logical task = place a heavy premium on the content of the anecdote & did not reason logically

Question 4

mary Henle - failure to accept the logical task

Answer 4

• failed to accept logical task = place a heavy premium on the content of the anecdote & did not reason logically
• ppl pay attention to semantics & content but ignore underlying logical structure
• ppl misunderstand what it means to be logical

Question 5

deductive reasoning task

Answer 5

• takes effort to make deductions
• can form general premise to make precise conclusions
• 2 statements of facts (premises), results from premises (conclusion)

Question 6

classical syllogism (4) ** PRACTICE DRAWING

Answer 6

1. universal affirmative
2. particular affirmative
3. universal negative
4. particular negative

Question 7

universal affirmative (classical syllogism)

Answer 7

• relationship between 2 categories is universal for all members
• 2 possible forms
  1. all members of category A are contained within larger category B
  2. All A are B

Question 8

particular affirmative (classical syllogism)

Answer 8

• suggests that some members of one category can also be members of another category
• 4 drawing versions
  1. some B are A - members of category A are also members of B but there are many members in B which are NOT members of A

Question 9

universal negative (classical syllogism)

Answer 9

• expresses a relationship between 2 concepts for which there is absolutely NO overlap
• does not give us much information about categories

Question 10

particular negative

Answer 10

• some members of one category are not members of another category
• “Some A are NOT B”

Question 11

modus ponens deduction

Answer 11

• affirming the antecedent, 1st premise introduces an “if-then” statement & 2nd premise confirms the antecedent (if statement) allowing a valid decision to be made about the consequent (then statement)

Question 12

modus ponens example

Answer 12

premise 1: if the cat is hungry then she eats her food
premise 2: the cat is hungry
conclusion: therefore, she eats her food

Question 13

modus tollens deduction

Answer 13

• form of conditional reasoning that denies the consequent
• 1 premise introduces an “if-then” statement, the 2nd premise denies the consequent (then statement) allowing for a valid decision to be made about antecedent (if statement)

Question 14

modus tollens example

Answer 14

premise 1: if the cat is hungry then she eats her food
premise 2: she does not eat her food
conclusion: therefore the cat is not hungry

Question 15

Wason card selection task

Answer 15

• Ps are showed 4 cards & are given a rule to evaluate & told to indicate minimum number of cards to turn over in order to verify if rule is true
• ppl suggest turning card “4” & “A” but should do “A” & “7” b/c 7 looks to disconfirm the rule
  WHY
• limitations in attention & working memory capacity
• easier to pick 2 cards to confirm hypothesis

Question 16

deontic selection task

Answer 16

• permission schema is easier for ppl to understand b/c when thinking about categories it makes sense to think about something is but not what something is NOT
• Ps are given rule & need to indicate minimum number of cards they need to turn over to evaluate rule
• ppl typically check age of beer drinker & what 17 year old is drinking
  WHY
• task appeals to permission schema which limits number of hypotheses that need to be considered