#5 - Byrne: One of our club’s bylaws specifies that any

[SGD2021]

Hello,

Does this type of description of a flaw "Assumes there is only one sufficient condition when there could actually be others" only apply to mistaken negations? (or could it also apply to mistaken reversals like it seems to do here in this question?)

Is it necessary to distinguish between the two (mistaken reversal or mistaken negation) when doing flaw questions if the descriptions can often be interchangeable?

Thank you!

[Robert Carroll]

SGD2021,

Mistaken Reversal and Mistaken Negation are in fact the same mistake - they are logically equivalent, as they are contrapositives of each other, So for a Flaw question, using language that describes one will describe the other. They are interchangeable.

So while the answer choice can actually apply to both, it seems to me as if the answer is just describing Mistaken Reversal directly - it assumes there is only one sufficient condition...so if there's only ONE sufficient condition, that condition will ALWAYS be found whenever you find someone suspended, so it's also thinking that sufficient condition is necessary. As I said, even if this were a Mistaken Negation, answer choice (B) should apply because MR = MN, but in this case we don't even need to go that far - answer choice (B) is directly stating a Mistaken Reversal.

Robert Carroll

[Capetowner]

SGD2021,

Mistaken Reversal and Mistaken Negation are in fact the same mistake - they are logically equivalent, as they are contrapositives of each other, So for a Flaw question, using language that describes one will describe the other. They are interchangeable.

So while the answer choice can actually apply to both, it seems to me as if the answer is just describing Mistaken Reversal directly - it assumes there is only one sufficient condition...so if there's only ONE sufficient condition, that condition will ALWAYS be found whenever you find someone suspended, so it's also thinking that sufficient condition is necessary. As I said, even if this were a Mistaken Negation, answer choice (B) should apply because MR = MN, but in this case we don't even need to go that far - answer choice (B) is directly stating a Mistaken Reversal.

Robert Carroll

But is it fair to say an answer choice describing a mistaken reversal would not be correct if a mistaken negation occurs in the stimulus (and vice versa)? On this basis I eliminated C.

[Jeff Wren]

Hi Capetowner,

The LSAT's description of conditional errors can be worded very specifically or more broadly. A general answer stating "the argument confuses a sufficient condition for a necessary condition" (or vice versa) could describe either a Mistaken Negation or a Mistaken Reversal.

However, if you do encounter two answer choices describing errors in conditional reasoning, read each one very carefully to determine which answer exactly matches what occurs in the stimulus.

A good example of this occurs in question 17 of section 3 of PrepTest 23 (the Oct. 1997 LSAT). Unfortunately, this question can be difficult to find as PrepTest 23 was not used in the newly numbered tests (post logic games), although it is available in our Testing and Analytics package.

Here is a link to the forum explanation for that question.

viewtopic.php?f=636&t=11422