Logical Reasoning

PT103 · S1 · Q21 Not all tenured faculty are full

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Not all tenured faculty are full professors.

Conclusion

Not all faculty members Not all X's are Y in Linguistics are full (Some X's are ~Y) professors.

Evidence

Every faculty member All X's are Z in Linguistics has tenure

Not all tenured faculty Not all Z's are Y are full professors (Some Z's are ~Y)

Evaluate

This argument is trying to make a Trait Overlap (or non-overlap) inference, using quantifiers. Generally speaking, if a Parallel Flaw argument has quantifiers, we can find the right answer without thinking about why the argument is flawed, as long as we've properly noted its structure.

The argument tries to All X's are Z combine these two ideas Some Z's are ~Y

in order to derive Some X's are ~Y

That's not legal. Consider this similarly flawed argument:

All former Presidents are men. Some men have gone to the moon. Thus, some former Presidents have gone to the moon.

Goal

Find an argument combining an All/None premise with a Some/Not All premise, in order to derive a Some/Not All conclusion.

The trigger of the All/None statement should be one of the two ideas in the conclusion.

The overlapping term in the two premises should not be in the conclusion.

Premise 1: All A's are B Premise 2: Some B's are ~C Conclusion: Some A's are ~C

21.

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

  1. Although all modern office towers

    Weak Premise Match

    The outcome (right side) of the conditional premise should show up again in the 2nd premise as the same idea (not as the negated version of the idea). And it should be the subject of the 2nd premise, not the backend. Original Argument This Argument Premise 1: All A's are B All MOT's are C. Premise 2: Some B's are ~C Some OB's are ~C. Conclusion: Some A's are ~C Some OB's are ~MOT.

    24% picked this

  2. All municipal hospital buildings are

    Weak Premise Match

    The outcome (right side) of the conditional premise should show up again in the 2nd premise as the subject of the 2nd premise. Original Argument This Argument Premise 1: All A's are B All MHB's are M. Premise 2: Some B's are ~C Some MHB's are ~F. Conclusion: Some A's are ~C Some M's are ~F.

    5% picked this

  3. Correct

    Although some buildings designed by

    Why this is right

    Original Argument This Argument Premise 1: All A's are B All GB's are DFA. Premise 2: Some B's are ~C Some DFAs are ~WP. Conclusion: Some A's are ~C Some GB's are ~WP.

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

    60% picked this

  4. Not all public buildings are

    Bad Premise Match

    The two premises are Some / Not All statements, and the conclusion is an All. We wanted an All in the premise and a Some / Not All conclusion, so this one isn't worth digging into.

    8% picked this

  5. Although some cathedrals are not

    Weak Premise Match

    The outcome (right side) of the conditional premise should show up again in the 2nd premise as the subject of the 2nd premise. Original Argument This Argument Premise 1: All A's are B All C's are I. Premise 2: Some B's are ~C Some C's are ~BS. Conclusion: Some A's are ~C Some I are ~BS.

    4% picked this

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