Q22 - All intelligent people are nearsighted

[GRAMMOHAN.BUSINESS]

To me option (B) "All chickens have beaks..." seems a good choice but the answer is (D) John is happy..

Can someone make this clear to me..!

[noah]

Well, what are the two flaws in the problem?

[gplaya123]

Oh wow lolz
this question is realllllllly tricky.
As Noah has pointed out, this argument contains 2 fallacies not, just one.
The first obvious one is converse fallacy

A -> B
B
----
A

Basically this is what it looks like and that argument is invalid.
Yet both B and D have this...

The difference is that the original argument says "I have super B" therefore "I must be super A," which is I could say part to whole fallacy. Just because u have super something or so called "very near-sighted" physique, that doesn't make you a genius overall.

D does this and B doesn't.

[noah]

Thanks for stepping up gplaya. I'm in agreement.

The original argument has two flaws: it's reversed logic and it assumes that there's a proportional relationship between intelligence and nearsightedness, when all we know is that one requires the other.

(D) has the same issues: just because tall people are happy doesn't mean that happy people are tall. And, just because tall people are happy doesn't mean that taller people are happier--nor does it mean that happier people are taller!

(A) is tempting, but we don't see the proportionality flaw. Instead, we are told intel --> near, and it concludes - near --> stupid instead of - near --> - intel. This might be a screw-up of the logic (who says that folks that are not intelligent are stupid? could there be a middle ground?) but there's nothing about "more this means more that."

(B) shows us reverse logic, but it has no "more this means more that."

(C) is just ridiculous! If pig --> 4 legs, where do we learn anything about size? Perhaps we can say there's an issue of "more this more that," but it's not based on a given conditional relationship involving those terms: where is there a statement about legs and size?

(E) is tempting. We learn that genius --> very near, and it concludes that genius --> very near. There's no flaw in this argument!

[tzyc]

I thought the stimulus is like:
All A is B.
C is B.
Thus C is A

And (D) applies to this.

But then I think (B) applies to this...
All chikens (A) have beaks (B)
The birds (C) has (B)
Thus (C) is (A)...

Or is it because the verb is different (have instead of is) so that makes (B) wrong...?
I did not see the reverse logic...

[noah]

I thought the stimulus is like:
All A is B.
C is B.
Thus C is A

And (D) applies to this.

But then I think (B) applies to this...
All chikens (A) have beaks (B)
The birds (C) has (B)
Thus (C) is (A)...

Or is it because the verb is different (have instead of is) so that makes (B) wrong...?
I did not see the reverse logic...

If you have A --> B and C --> B, can you get to C --> A? No. It's some sort of off logical move (perhaps not formally "reversed" but something is screwy!)

Take a look at my first post for my other idea about why (B) is wrong.

(BTW, sorry about the long silence - about a week or two slipped through my hands way back when!)