Thank you for your well thought-out response nusmavrik! As a teacher, I love to see students tackle the concepts so willingly, and think about them in such great detail.
As I suspected, and as you suggest in your first paragraph, our disagreement is one of semantics, and is likely academic. However, please allow me the opportunity to re-interpret your evidence so that it can just as easiliy suppot my view. Your evidence is a great example:
Quote:
The number of murder in American cities is correlated with large number of churches in the cities. Hence church cause murder in the cities.
There is a strong correlation between the # of churches and the # of murders in American cities: the more churches, the more murders. However, there is no causation at work here (churches don't cause murders, and murders don't cause the building of churches), because both of these factors are caused by a third factor: the SIZE of the city. (larger cities have both more churches and more murders.)
This third factor is the one OUTSIDE the scope or not mentioned in the passage. It works wonderfully here.
Now, another way of looking at this is how the author is
reasoning; not just what was and was not "mentioned" in the passage. That the author failed to consider alternative causation (ie, "third factor") is a flaw in reasoning...Thus, any fact that points to an alternative cause weakens (while any choice that removes an alternative cause strengthens) the argument
by reference to this flaw in reasoning. Facts that have to do with the author's flaw in reasoning
ipso facto have to do with the author's reasoning. Thus, facts that deal with overlooked causes lie within the ambit or scope of the author's reasoning/argument.
While they may SEEM outside the scope they are not truly outside the scope. In other words, on my view, just because a fact is not mentioned, does not mean that it is outside the scope because that fact still may have to do with the autor's
reasoning. Considering the question at hand, we can say that other modes of transportation don't have anything to do with the author's argument--choice C is outside the scope.
In short: I am taking "scope" to mean something that has to do with the author's reasoning explicitly or implicitly. You seem to be taking "scope" to mean something that was explicitly mentioned in the argument.
(I should also reiterate that scope is not your best friend in stn/wkn questions for the reason I discussed in my post above. I should also emphasize that a fact NOT mentioned in the passage may still stn or wkn an argument.)
However, our debate is very academic, and not necessarily most helpful. What
is important is that you arrive at an effective way of looking at it, and it sounds as though you have. So, let me leave you with a modified version of
MGMAT's tip:
In passages that CORRELATION and conclude CAUSATION, that connection can be destroyed in three ways:
(1) a choice that suggests alternative causation (most common on the GMAT)
(2) a choice that suggests that correlation is merely a coincidence
(3) the causation actually runs the other way around (i.e., the passage concludes that X causes Y, but in actuality Y causes X) (least common, and at Kaplan we call this "reversal of causality")
Some comments:
(1) and (2) are closely related. if, as per (2) a choice suggests the connection between x and y is a mere coincidence, then because everything has a cause, there must be some other cause--(1) is strictly implied. That's probably why
MGMAT lumps (1) and (2) together. I've found that many students benefit from viewing (1) and (2) separately because, in their first instance, some answer choices directly suggest alternative cause while some other choices (fewer but some) suggest coincidence.
Finally, it is an oversimplification to say that my (3)--reversal of causality--applies to ANY correlationbased causal argument. There are two types of correlation:
chronological (x before y)
simultaneous (x at the same time as y)
Reversal of cauasality CANNOT apply to chronological arguments. Let us consider an example:
"I had a headache. I took a tylenol, and my headache then went away. Thus, because I took the tylenol BEFORE the relief from my headache, my taking of the tylenol must have CAUSED my relief from the headache."
Let's now reverse this, and see if it makes any sense:
"The relief from my headache was the cause of my taking the tylenonl."
Does the argument make sense when reversed? Of course not. The temporal aspect prevents it from making sense. Thus, arguments of causation that are based on chronological correlation cannot be intelligibly reversed.
Of course, arguments of causation based on simultaneous correlation can be sensically reversed:
Did you get good grades because the teachers liked you or is it because the teachers liked you that you got good grades?