Self-study
Advertisement: Conclusion The dental profession knows that brushing with Blizzard toothpaste is the best way to fight cavities. ██ ████████ ████ █████████ ███ ████ ██████ ████ ███ ██████ ███████ ███████ █████ ██ ████████ ██ ███ ████ █████████ ███████████████ ███████ █████████ ██ █ ███████████
Method of Reasoning
The advertisers surveyed five dentists, each of whom agreed that Blizzard toothpaste’s tartar control formula is the most effective cavity-fighting formula available in a toothpaste. Based on these survey results, the advertisement claims that the dental profession knows that the best way to fight cavities is to use Blizzard toothpaste.
Identify and Describe Flaw
There are two cookie-cutter flaws in this argument:
Too small samples: Five dentists isn’t enough to make a claim about the beliefs of the entire dental profession!
Hasty generalization: The dentists agree that Blizzard’s toothpaste formula is the best toothpaste formula for fighting cavities, but the conclusion is about the best way to fight cavities overall. Maybe flossing regularly is more important than the toothpaste you use!
25.
The flawed reasoning in which ███ ██ ███ █████████ ██ ████ ███████ ██ ███ ██████ █████████ ██ ███ ██████████████
a
The nation's voters ████ ████ █████ ██ ███ █████████ █████ ████████ █████ ██ ████ ███ ███ ███████ ██ ███ ██████ ███████ ████ ████ ████ █████ █████ ██ █ ████ ███████ ███████
Wrong flaw. While (A) does commit the error of using a too-small sample (ten voters is not enough!), its second flaw is different from the one in the stimulus. Here, the premise is about something that’s pretty distinct from the conclusion (popular leadership doesn’t necessarily contribute to having the best policies). In the stimulus, the premise is about something that directly impacts the subject of the conclusion (we’re told that the tartar control formula does help fight cavities!)
b
Some of the ████████ ██████ ███████ ████ █████ ██ ███ █████████ ███ █████ ██ ████ ███ ███ ███████ ██ ███ ███ ██████ ██ █████████ ████ ██████ ████ ███ ████████ █████ ██ █████████ ██ █████ ██ ███ ████ ████████ ███ ███ ██████ ██ ██████
Only one of the flaws. Here, we don’t have the too-small sample flaw: the conclusion is about some of the nation’s voters, and the premise gives us enough information to support a statement about that group (ten voters are some voters). (B) does commit the hasty generalization flaw from the stimulus—even if the voters think the policies Gomez is committed to are the best, that doesn’t mean they believe that Gomez is the best! Maybe they don’t think she’d be capable of passing the policies.
c
The nation's voters █████████ ███████ ████ █████ ██ ███ █████████ ███ █████ ██ ████ ███ ███ ███████ ██ ██████ █████████ ██ ██████ ██ ███ ███████ ███ ████ ██████ ████ ███ ████████ █████ ██ █████████ ██ █████ ████ ███ ██████ ████ ████ █████ █████████ ██ ███ ██ ███ █████ ███████████
Wrong flaw. (C)’s sample isn’t too small—they polled thousands of voters! (C)’s hasty generalization error is also less severe than the one in the stimulus. The flaw in (C) is that voters thinking that Gomez’ policies are the best doesn’t mean voters generally believe that Gomez herself is the best. But (C)’s conclusion that voters “generally believe” something is easier to support than the stimulus’ claim that dentists “know” something.
d
The nation's voters ████ ████ ████████ █████ █████ ██ ███ ████ ███ ██ ████ ███ ███████ ███ ███ ██████ ██ ██████ ███ ██████ ████ ███ ████████ █████ ██ █████████ ██ █████ ████ ███ ██████ ████ ████ ███ █████ █████████
The authors surveyed ten voters, each of whom agreed that Gomez’ policies would help the nation more than any other policies. Based on these survey results, the authors claim that the nation’s voters know that the best way to help the nation is to elect Gomez. This commits the same two cookie-cutter flaws as the stimulus: it uses too small a sample size, and it makes a hasty generalization (believing that Gomez’ policies are the most helpful doesn’t mean someone believes that the best way to help is by electing Gomez!)
e
We know that ████████ █████ █████ ██ ███ ████ ██████ ███ ███ ██████ ██ ██████ ████████ ██ ███ ██████ ██ █████████ ████ ██████ ████ ████████ █████ █████ ████ ███ ███████
Wrong flaw. This is even weaker than the stimulus! At least the stimulus tells us that Blizzard’s formula is the most effective. (E) only tells us that Gomez would help—he might not even be the most helpful candidate!