PHIL 111: Lecture 6 (Fallacies)
equivocation
a term is used in two different senses in the same argument; this way there is no way to infer a conclusion from the logical form
I just saw ad advertisement for a chemistry textbook I need next semester. They had three options: $59 for e-book only, $125 for hardcopy only, and $125 for e-book and hardcopy. I'm definitely going for the $125 e-book and hardcopy, even though I really only need the e-book. It's such a good deal comparatively, I can't turn it down.
anchoring bias
Crystals have been used for healing for centuries, and different cultures used them. So, I think we should all use them.
appeal to consensus
I believe in astrology and read my horoscope every day. No one has ever disproved it, and that's good enough for me.
appeal to ignorance
Please don't make us do a final exam in logic! We will not be able to finish our holiday shopping and have to get substandard gifts for our friends and families, which would be just too upsetting.
appeal to pity
We got three bids from contractors to fix our roof. We took the Smith Company bid because Joe Smith's mom recently died, and he's very sad. Getting some business may cheer him up.
appeal to pity
false dilemma
argument in which two extreme options are presented as the only options (when in fact there are other intermediate options)
We don't think that final exams in logic are educationally useful or fair. In a poll of logic students, 85% of them voted against the use of logic exams.
biased statistics
High-priced: the meal we ate in Paris was delicious, but very high-priced.
borderline
Red: I love the color red; it's my favorite.
borderline
Trim: Senator Smith looks very trim in that suit.
borderline
Wide: I hope the doorway is wide enough to move that sofa into the room
borderline
fallacy of composition
conclude that a group as a whole has some property just because a portion of it's members do
fallacy of division
conclude that individual members of a group have some property just because the larger group does
My outing club is going on their Mt. Washington hike this weekend, despite the weather forecast for 80% chance of sleet and snow. I asked the leader of the trip about this, and she said, "but there's a 20% chance of clear and crisp weather. That's good enough for me."
framing effects
Jenny and Johnny both failed their first chemistry test. Jenny was upset, but reminded herself that she had slept badly the night before and had a headache during the test, which made it hard for her to concentrate. When Johnny told Jenny her failed, she said to him, "well, it's totally your fault. You probably just spent too much time playing video games online instead of studying. You've got to be less lazy and learn to value your classes!"
fundamental attribution error
biased statistics
happens when you draw a conclusion based on a sample that lacks variety
misleading vividness
happens when you draw a conclusion based on one vivid case or experience, rather than a large body of knowledge
hasty generalization
happens when you draw a conclusion based on too small a sample
I don't think that final exams in logic are educationally useful or fair. I asked my friend, and we both agree that they should be abolished.
hasty generalization
Cassandra and her friends Jolene and Margaret, all first graders, started the "we hate boys" club. Asked why they did this, Jolene said, "Boys are bad because they play different games than we do. We don't like those games, so we don't like boys, either".
in-group bias
appeal to ignorance
instead of giving evidence in favor of a belief you say a person should believe it because there is no evidence that it is false
ad hominem
instead of providing reasons against a conclusion you say that we shouldn't believe it because of the person who said it (personal attack on the person
appeal to consensus
instead of providing reasons for a conclusion one says that everyone (or lots of people) believe it too
appeal to authority
instead of providing reasons for a conclusion you say that some so-called expert has endorsed it or believes it (but they are not truly experts in the field)
appeal to pity
instead of providing reasons for a conclusion you say that the person should believe it because they feel sorry for you
I'm sorry to report that George is blue.
lexical
Jan's house is really hot.
lexical
Peter got held up on the way to the movies.
lexical
appeal to force
making a claim and trying to persuade someone through intimidation or threats rather than reasoning
Exercise is really over-rated for health. My great uncle never went to the gym in his life, and he lived to be 93.
misleading vividness
I think MIT engineers are really undertrained and ignorant; I met one once who got a bunch of answers wrong when he interviewed for my family's company
misleading vividness
Professional: Sally is my role model—she is a real professional writer.
multiple criteria
Teacher: Joe strikes me as a great teacher.
multiple criteria
That wallpaper has got to go—it's so ugly!
multiple criteria
I'm against curbside recycling. Two weeks after it started, my house was broken into. It's certainly because of the recycling that this happened.
post hoc
My niece's art project is quite good.
relative term
Tim's head is absolutely huge!
relative term
slippery slope
says that adopting one policy or action will lead invariably to a series of other policies or actions (quite different/unrelated) also being taken
Once we start banning leaf blowers in the neighborhood, it will probably lead to no use of lawn mowers, weed trimmers, and soon we will all have to maintain our lawns with scissors.
slippery slope
Headline reads "stud tires out"
structural
Joe is taking a Greek dance class.
structural
We need more understanding administrators.
structural
Ken is feeling dissatisfied with his major in accounting. He thought he would like the straightforward approach. However, the first semester of his senior year, he took a poetry class and fell in love with literature. His professor urged him to change his major, as Ken seems well-suited to majoring in English and going to graduate school. However, Ken is sticking with his (now-loathed) accounting major, saying "I've already spent so much time on it, and might as well finish it.
sunk cost bias
false analogy
you claim that because two things share one property they also share another property (even if this conclusion is not true)
post hoc
you make the conclusion that because B happens after A, it follows that A caused B
