Logic Breakdown

Passage Summary: Terry thinks 'bad' actions are 'good' if they have good results. Pat agrees they are 'good' but disagrees with Terry's logic, even though Pat's own logic seems to contradict the very conclusion being supported.

Conclusion: Both Terry and Pat conclude that certain actions labeled as 'bad' by society are actually 'good.'

Reasoning: Terry argues that because good actions must have favorable results, bad actions with favorable results are good. Pat agrees with the conclusion but claims no bad actions actually have favorable results.

Analysis: Terry is guilty of a classic formal logic error: confusing a necessary condition for a sufficient one. Terry says 'If Good, then Favorable,' then finds something 'Favorable' and incorrectly concludes it must be 'Good.' Pat, on the other hand, is having a bit of a meltdown in the consistency department. Pat agrees with Terry's conclusion but then asserts a premise—that no bad actions have favorable consequences—which actually destroys the specific evidence Terry used to reach that conclusion. Look for an answer that identifies Terry's 'Mistaken Reversal' and Pat's internal contradiction.

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21.

Which one of the following correctly describes both an error in Terry's reasoning and an error in Pat's reasoning?

Correct Answer
D
Both argue as if a necessary condition were sufficient. Terry has G -> F and uses the existence of F to infer G (mistaking necessity for sufficiency). Pat has B -> ~F and uses the existence of ~F (within some good actions) to infer B (again, treating a necessary condition for B as if it were sufficient). Choice D precisely captures this necessary/sufficient confusion.
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