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- Wed Mar 15, 2023 2:07 pm
#99907
Hi ashpine,
First, if the conclusion in the stimulus had read "So it is not true that whoever likes turnips like potatoes," then that would have been a valid argument since we know that there is a least one person (the author's father) who likes turnips but does not like potatoes.
Second, the conclusion of Answer A is
it is not true that:
Some paperbacks are expensive (diagrammed PB some Exp)
This is equivalent to the statement that No paperbacks are expensive, or paperbacks are never expensive
(diagrammed PB <-|-> Exp if you use the Double-Not Arrow)
(you could also diagram it PB -> not Exp and the contrapositive would be Exp -> not PB)
So while the argument in Answer A is flawed, it is not identical in form to the flaw in the stimulus since the terms are logically different in the conclusion.
As mentioned above, this question involves Formal Logic, which is discussed in detail in the lesson 8 homework online of our LSAT class and in Chapter 13 of The Logical Reasoning Bible.
First, if the conclusion in the stimulus had read "So it is not true that whoever likes turnips like potatoes," then that would have been a valid argument since we know that there is a least one person (the author's father) who likes turnips but does not like potatoes.
Second, the conclusion of Answer A is
it is not true that:
Some paperbacks are expensive (diagrammed PB some Exp)
This is equivalent to the statement that No paperbacks are expensive, or paperbacks are never expensive
(diagrammed PB <-|-> Exp if you use the Double-Not Arrow)
(you could also diagram it PB -> not Exp and the contrapositive would be Exp -> not PB)
So while the argument in Answer A is flawed, it is not identical in form to the flaw in the stimulus since the terms are logically different in the conclusion.
As mentioned above, this question involves Formal Logic, which is discussed in detail in the lesson 8 homework online of our LSAT class and in Chapter 13 of The Logical Reasoning Bible.