QUESTION TEXT: Research indicates that 90 percent of extreme…
QUESTION TYPE: Flawed Reasoning
CONCLUSION: Tom must be an insomniac.
REASONING: Almost all insomniacs drink a lot of coffee. Tom drinks a lot of coffee.
ANALYSIS: This mixed up correlation and causation.
If you’re an insomniac, sure, you’re likely to drink coffee.
But we don’t know that coffee drinkers are insomniacs. That’s backwards.
Maybe 90% of the entire population drinks coffee, both insomniacs and restful sleepers.
___________
- This misstates the evidence. We don’t know how many coffee drinkers are insomniacs.
- The argument never said coffee was the only cause of insomnia. You might get insomnia without coffee, and you might sleep well even if you drink coffee.
- CORRECT. We have no idea how well coffee drinkers sleep. We only know that people who can’t sleep well drink coffee. But maybe everyone drinks coffee.
- There’s no problem with this, it can be perfectly find logic. For example: “All dogs have tails. Therefore Fido the dog has a tail.”
- The conclusion just says it’s “likely” that Tom can’t sleep. The argument didn’t say coffee always causes insomnia.
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