Classic Flaws

Question 1

bad conditional reasoning

Answer 1

read backwards without negating

read forward and negate

Question 2

bad causal reasoning

Answer 2

the authors sees that two things are correlated

the author concludes that those two things are causally related

Question 3

piece ≠ puzzle

Answer 3

author states that a member of a group has a certain characteristic
author concludes that the entire group also has that characteristic

Question 4

puzzle ≠ piece

Answer 4

author states that an entire group has a certain characteristic
author concludes that a member of that group has that characteristic

Question 5

overgeneralization

Answer 5

author discusses something having a certain characteristic

author concludes that other things also have characteristic

Question 6

survey problems

Answer 6

survey exists
author concludes things based on that survey
there are many things wrong with the survey

Question 7

possible survey problems

Answer 7

biased samples 
biased questions 
contradictions 
lying survey participants 
small sample size

Question 8

false starts

Answer 8

there’s a study with two groups
research assumes the groups are the same in all ways except those pointed out as part of the study
researcher concludes that the differences in the study results are due to the key difference focused on in the study

Question 9

lack of evidence ≠ evidence of lacking (type of possibility ≠ certainty flaw)

Answer 9

something is not necessarily true/false, therefore it cannot be true/false

Question 10

proof of evidence ≠ evidence of proof (type of possibility ≠ certainty flaw)

Answer 10

something could be true/false, so it must be true/false

Question 11

implication

Answer 11

someone has a belief
the author mentions a factual implication of that belief
author concludes that the “someone” believes the implication of that belief

Question 12

limiting a spectrum (type of false dichotomy flaw)

Answer 12

author eliminates one of the options

author concludes the second option must be true (forgetting about the unchanged option)

Question 13

limiting options

Answer 13

author outlines two possible options
author eliminates one of the options
author concludes the second option must be true

Question 14

straw man

Answer 14

someone makes a claim

another person responds to a completely different claim, but acts as if they responded to the first person

Question 15

ad hominem

Answer 15

someone makes a claim
another person insults the first person
second person concludes that the first person’s claim is false

Question 16

circular reasoning

Answer 16

author concludes something

author presents premises that assume the conclusion is already true

Question 17

equivocation

Answer 17

author initially uses a word intending one meaning

author concludes something using the other possible meaning of that word

Question 18

appeal fallacies

Answer 18

author says that a person or group believes something

author concludes that the “something” must be true

Question 19

irrelevant

Answer 19

author supplies a few premises

author concludes something that is unrelated to the premises

Question 20

%-to-# (type of percentages ≠ numbers flaw)

Answer 20

author notes that a percentage went up or down

author concludes that the associated real number also went up or down

Question 21

-to-% (type of percentages ≠ numbers flaw)

Answer 21

author notes that a number went up or down

author concludes that the associated percentage also went up or down