Fistail wrote:
All intelligent people are nearsighted. I am very nearsighted. So I must be a genius.
Which one of the following exhibits both of the logical flaws exhibited in the argument above?
(A) I must be stupid because all intelligent people are nearsighted and I have perfect eyesight.
(B) All chickens have beaks. This bird has a beak. So this bird must be a chicken.
(C) All pigs have four legs, but this spider has eight legs. So this spider must be twice as big as any pig.
(D) John is extremely happy, so he must be extremely tall because all tall people are happy.
(E) All geniuses are very nearsighted. I must be very nearsighted since I am a genius.
This one must be LSAT. I just learn this concept recently, so I'll try to give my detailed explanation....
Anyways, the logic here is that:
Stem: intelligent -> nearsighted
Conclusion: nearsighted -> intelligent
This conclusion is flawed because the reversed is not true. The only thing we can conclude from here is that: not nearsighted -> not intelligent
A: intelligent -> nearsighted, not nearsighted -> not intelligent
This is actually a valid conclusion and it is not flawed. Therefore, it is not the right answer. INCORRECT
B. Chicken -> have beaks, have beaks -> chicken
This sounds about the same as the stem.
C. pig -> 4 legs, 8 legs -> twice as big as pigs
No correlation what so ever, INCORRECT
D. Tall -> happy, happy -> tall
This also sounds the same as the stem
E. Genius-> very nearsighted, Genius -> very nearsighted
This is not the same as the stem either...INCORRECT
So we are down to B or D
Since they are similar logic, we need to look at the stem closely. Once you do, you see that genius is an extreme form of intelligent. So the revised stem should be
intelligent -> nearsighted
extremely nearsighted ->
extremely intelligent
Now, compare B and D again
For B,
Chicken -> have beaks
have beaks -> chicken
For D,
Tall -> happy,
Extremely happy ->
Extremely tall
D must be the correct answer.
close
