voodoo_child wrote:Though myopia, nearsightedness in one or both eyes, is believed to be a hereditary disorder, scientists propose that environmental factors such as stress and nutrition may also play a role in the progression of the disease. Adults who, as children, were diagnosed with mild cases of myopia and whose cases of myopia have remained relatively mild report that they have always refrained from reading in dim light; thus, a child diagnosed with a mild case of myopia can increase the likelihood that his or her condition will not become significantly more severe by refraining from reading in dim light.

A flaw in the argument above is that it


(A) provides reasons for the validity of its conclusion that presuppose the validity of that conclusion

(B) proceeds as though a condition that by itself is enough to guarantee a certain result must necessarily be present for that result to occur

(C) assumes without evidence that a behavior and a state which occur simultaneously share an underlying cause

(D) concludes that a practice causes a phenomenon when, at best, only an association between the two has been established


(E) fails to acknowledge that the stability of a condition experienced by a subgroup of individuals within a greater population will not necessarily be shared by the entire population

OA - D

So the stimulus makes a causal generalization from a specific study. In summary it says that because "[some] Adults [presumably in a study] who, as children, were diagnosed with mild cases of myopia and whose cases of myopia have remained relatively mild report that they have always refrained from reading in dim light" that "a child diagnosed with a mild case of myopia can increase the likelihood that his or her condition will not become significantly more severe by refraining from reading in dim light"

Prephrase: The flaw in the argument is that a general causal relationship is implied based on a small study which can only produce a correlation.

OR

Correlation does not indicate causation.

Scanning the answer choices, (D) is a pretty good match for the prephrase.

Just for kicks, going through the others

(A) is akin to 'circular reasoning' which isn't present in this argument
(B) is akin to the 'necessary and sufficient' conditional reasoning error. this argument does have an if-then argument but the structure of the if-then argument isn't flawed here.
(C) is akin to a causal error but there aren't two items which share an underlying cause.
(E) is akin to a generalization error. this is sort of present in this argument but not in the sense that it is indicating. there isn't any "instability" in any part of this argument.

i got stuck to E

I got stuck between D and E
both of them seem correct and applicable to this argument
any expert opinion?

Mehrasa,

Luke's explanation is attractive. You could refer that. IMO D

E is a bit tricky. The argument does contain 2 subgroups (adults and children) within a generalized group (people). But the flaw in the argument is not that the condition is only applicable to one subgroup (ie adults / children) and the conclusion refers to another. The premise is that if, as children, people with myopia refrain from reading in dim light they have a lower chance of the myopia getting worse as adults. The premise is actually relating the two subgroups and so is the conclusion.

An example of (E) as an error might be something like "Children ages 10-14 who read in dim light have a higher chance of getting myopia within 3 years. Thus if you are an adult ages 30-34 and you read in dim light you will have a higher chance of getting myopia within 3 years." That argument doesn't take into account that, for example, children are better able to damage their eyes by reading in dim lights than adults.

Hopefully that's helpful.