Discussion
Which one of the following uses reasoning that is most similar to that used in the above argument?
*This question is included in Nova Press: Set E - If/Then Logic Practice, question #6
| (A) | There’s a cat in this house. There must be, because I’m allergic to cats; and I just sneezed. |
| (B) | ... |
| (C) | ... |
| (D) | ... |
| (E) | ... |
| (F) | ... |
The solution is
Posted: 12/15/2011 21:59
No explanation for the correct answer to this question. Please explain why (A) is the answer.
Posted: 12/17/2011 02:23
Let T stand for “the rebels truly want a political settlement,” and let S stand for “they will stop shelling the Capitol.”
Now the argument can be symbolized as:
T → S
S
∴T
This diagram clearly shows that the argument is committing the fallacy of affirming the conclusion. The answer will commit the same fallacy.
Begin with choice (A).
The clause “I’m allergic to cats” contains an embedded if-then statement: “If there is a cat around, I start sneezing.” This in turn can be symbolized as C→Sn, where C stands for “there is a cat around,” and Sn stands for “I start sneezing.”
Substituting these symbols into the argument yields:
C → Sn
Sn
∴ C
The diagram shows that this argument has the same structure as the original argument.
The answer is (A).
Now the argument can be symbolized as:
T → S
S
∴T
This diagram clearly shows that the argument is committing the fallacy of affirming the conclusion. The answer will commit the same fallacy.
Begin with choice (A).
The clause “I’m allergic to cats” contains an embedded if-then statement: “If there is a cat around, I start sneezing.” This in turn can be symbolized as C→Sn, where C stands for “there is a cat around,” and Sn stands for “I start sneezing.”
Substituting these symbols into the argument yields:
C → Sn
Sn
∴ C
The diagram shows that this argument has the same structure as the original argument.
The answer is (A).