Logical Reasoning

PT134 · S3 · Q23 Most auto mechanics

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Most auto mechanics have extensive experience.

Evidence

Most auto mechanics have Most subtype X's extensive experience are A.

Most mechanics with Most X's who extensive experience are A are B. understand electronic circuits

Conclusion

Most auto mechanics Most subtype X's understand electronic circuits. are B.

Evaluation

The author is performing some illegal "most" math.

We can usually only make an inference with "most" claims if both of them are about the same group. If "most auto mechanics are X" and "most auto mechanics are Y", we can infer that at least one of them is both X and Y.

But this argument switches from "most auto mechanics" to "most mechanics". It's also illegally concluding "most auto mechanics", when we're not even convinced that there are "some" with this property.

We can spot everything we need to match the correct answer just by tracking the three "most" claims and making sure they try to chain together. But if you want to see why this structure is flawed, consider this example: .

Goal

We need an author to take a big category and say that most of them have a trait. Then she needs to say most of the members of a broader related category with that trait have a second trait. Then she has to conclude that most of the narrow category has that second trait.

23.

The pattern of flawed reasoning in which one of the following arguments is most similar to that in the argument above?

  1. During times of the year

    No Most Claims

    The fact that none of these claims are based on "most" means that we won't be replicating the structure or flaw of the original.

    7% picked this

  2. The most common species of

    Weak Premise / Conclusion Match

    The conclusion says "few do", which means "most don't", so we can potentially still use this one. The biggest problem is that the first sentence is not "Most X's are A", it's "the most common type of A is X." That doesn't work. The most common type of religious affiliation is Islam, but that doesn't mean that "most people are Muslims". A matching argument might have said, "Most canaries are migratory. Most birds that migrate have left by end of November. Thus, most canaries have left by end of November."

    5% picked this

  3. It is not surprising that

    Only One Premise

    There's only one premise here, so it won't be able to match the structure or flaw of the original.

    1% picked this

  4. Most nature photographers find portrait

    Weak Premise / Conclusion Match

    The two "most" premises are supposed to sort of chain together: Most subtype X's are A. Most X's that are A are B. These two "most" premises are about different groups altogether. Most nature photographers are A. Most X's are A Most portrait photographers are B. Most Y's are B The second premise should have sounded like, "Most nature photographers who find portrait photography boring enjoy photographing dignitaries" and then it would have concluded, "Thus, most nature photographers enjoy photographing dignitaries".

    8% picked this

  5. Correct

    Most snow-removal companies run lawn-care

    Why this is right

    This takes "most" of a "most". Most snow-removal Most subtype X's are A. companies run lawn care during the summer Most companies that Most X's are B. run care during summer hire additional people in summer Thus, most snow Most subtype X's removal companies are B. hire additional people in summer

    Skill tested: Parallel Flaw · how this choice captures the argument's function is the move to repeat next time.

    79% picked this

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