Pharmacists recently conducted a study with respect to the reasons their customers purchased eye drops to soothe eye dryness. Dry eyes were more frequently experienced by customers who wore contact lenses than by customers who did not wear contact lenses. The pharmacists concluded that wearing contact lenses, by itself, can cause contact wearers to have dry eyes.

Which one of the following statements, if true, most seriously undermines the pharmacists' conclusion?

(A) An inherited condition can cause both weak eyesight and dry eyes.
(B) Physical exertion causes dry eyes in many people who wear contact lenses.
(C) Most people who have dry eyes do not wear contact lenses.
(D) Most people who wear contact lenses do not have dry eyes.
(E) Both weak vision and dry eyes cause headaches.

A,B, and E are out of scope since they are not related to the argument. Nowhere is mentioned about physical exertion, headaches or inherent causes. [u]"The pharmacists concluded that wearing contact lenses, by itself, can cause contact wearers
to have dry eyes. "[/u]
Then if most people who wear contact lenses do not have dry eyes scientists are wrong in their conclusion
So it seems D to me

1) Pharmacist study: reason why customers purchase eye drops to soothe eye dryness
2) Dry eyes experienced more frequently by customers who wore contact lens
3) Wearing contact lens cause dry eyes <-- conclusion

The conclusion is that wearing conact lens cause dry eyes. The choice that most immediately attack this conclusion, is (C). If most people have dry eyes and do not wear contact lenses, then it is not true that wearing contact lens is the cause of eye dryness.

(D) is close, but not good enough. All it says is most people who wear contacts do not have dry eyes to begin with.

I will choose C. I took a peep at your OA and am quite stunned it's A. To me, (A) is quite out of the scope since we're not even dealing with short-sightednes. It does suggests that dry eyes might be caused by inherited condition, but it does not attack the conclusion as much as C or D.

But the question explicitly sames "undermines the conclusion". So shouldn't we be looking for the conclusion, then attacking it. I understand your explanation just now. This is just what I thought.

okay, reading your arugment once more cleared my mind. Good one !! I've got to start my engines once more, been away too long

I think here the by itself plays a major role in choosing A rather than C.

I did pick A initially but B undermines argument as well. A says genetics is responsible for dry eyes and B says physical exertion. How do u decide which one weakens it MORE? both are examples of external factors causing dry eyes.[/b]

Decibel is right when he says that both A and B have external factors which can weaken the argument. My best guess is that in B, 'many people' still leaves doubt. It can happen that there are still some people who can be affected by dry eyes by just wearing contact lenses- we dont know for sure. In case of A, the choice is more absolute. my two cents.

Pharmacists recently conducted a study with respect to the reasons their customers pur- chased eye drops to soothe eye dryness. Dry eyes were more frequently experienced by customers who wore contact lenses than by customers who did not wear contact lenses. The pharmacists concluded that wearing con- tact lenses, by itself, can cause contact wearers to have dry eyes.
Which one of the following statements, if true, most seriously undermines the pharmacists’ conclusion?
(A) An inherited condition can cause both weak eyesight and dry eyes.
(B) Physical exertion causes dry eyes in many people who wear contact lenses.
(C) Most people who have dry eyes do not wear contact lenses.
(D) Most people who wear contact lenses do not have dry eyes.
(E) Both weak vision and dry eyes cause headaches.
_________________

My dad once said to me: Son, nothing succeeds like success.

This argument employs a common fallacy. That is if two things are happening together one causes other. It assumes that correlation means causation. Choice A correctly identifies the faulty reasoning and identifies the possibility of another condition which may be real cause behind both the problems of poor eyesight and dry eyes.

Rest other choices do not undermine the conclusion. that is they do not directly suggest in any way that contact lenses are not the cause of dry eyes"

Choice B has 2 problems, first it says Physical exertion causes dry eyes in many people who wear contact lenses. But many is not equivalent to 'all' . for proving causation many people is not the appropriate word to use. Even if we remove many then this statement can be interpreted in two ways, physical exertion causes dry eyes and not contact lenses. this does undermines the conclusion. But another interpretation may be wearing contact lenses cause physical exertion which in turn causes dry eyes. This interpretation will support the argument. In any case, the first reason - the usage of uncertain word 'many' itself eliminates this choice.

Choice C - this does not deals with issue itself.

Choice D - again -Most people ? may be most dont have, but still contact lenses can cause dry eyes in some.

Choice E. this does not deals with issue itself

Hi Aj85,

Choice A states: An inherited condition can cause both weak eyesight and dry eyes.

Isnt this choice out of scope since our target audience is people who wear contact lenses only and this choice also talks about people who do not wear contact lenses. Choice B talks only about people who wear contact lenses and says that physical exertion causes dry eyes and not wearing contact lenses. I agree many = not all but i believe this choice seems more to be a weakener than choice A since choice B talks about the people who wear contact lenses as stated in the passage and not about all people .

Please let me know.

Thanks!!!