All any reporter knows about the accident is what the press agent has said. Therefore, if the press agent told every...

Mehran August 26, 2013

The video explanation for this question is now live inside of LSATMax but I will explain here as well. Naz's video explanation approaches it from the contrapositive perspective but I will explain it here a different way just in case you find one easier to understand than the other.

So let's take a look at the argument:

"If the press agent told every reporter everything about the accident, then no reporter knows any more about it than any other reporter."

PAER ===> no R > R
R > R ===> not PAER

"If no reporter knows any more than any other reporter, then no reporter can scoop all of the other reporters."

no R > R ===> not S
S ===> R > R

"However, the press agent did not tell every reporter everything about the accident."

not PAER

"It follows that some reporter can scoop all of the other reporters."

S

So the argument is taking "not PAER" to conclude "S" but this is clearly flawed. From the transitive property, we know that:

PAER ===> no R > R ===> not S

Which allows us to conclude: PAER ===> not S

However, the author is using "not PAER" to conclude "S" which means he is assuming the statement actually says:

not PAER ===> S

Don't just negate! Remember, just because something is not a carrot doesn't necessarily mean it is not a vegetable. Similarly, just because the press agent did not tell every reporter everything about the accident doesn't necessarily mean that some reporter can scoop all of the other reporters.

(E) is testing this same concept but only from the first principle (i.e. PAER ===> no R > R). Just because "not PAER" does necessarily mean "R > R" (i.e. it is possible that no reporter knows any more about the accident than any other reporter, or "no R > R").

As for your question as to how to approach this question, keep in mind that Errors in Reasoning and Weaken questions are very similar. Here we are asked to identify the error in the reasoning, but we could have just as easily been asked to weaken the argument.

Hope this help! Please let us know if you have any other questions.

Batman March 18, 2014

As your sufficient and necessary lectures, you have taught that "No X's are Y's" is X - - > not Y or Y - - > not X, right? On the stimulus, "if the press agent told every reporter everything about the accident, then no reporter knows......" In this sentence, I am still confused how come you draw logical structure like this: PATERE - - -> no R >R
Doesn't "no reporter ....," which is necessary condition, itself include another sufficient and necessary logical structure according to lectures?

In a nut shell, "if the press...." Is sufficient condition and "then no reporter knows...." Is necessary condition. However, doesn't this necessary condition also have another sufficient and necessary condition due to "no X are y" phrase?

Please help~

Thanks,

sharpen7 March 6, 2018

Why did you not use a some statement like you did in question 29?

sharpen7 March 6, 2018

I am referring to the second sentence in #29,

Mehran March 8, 2018

@sharpen7 because the some statement here is actually negating a necessary condition.

"If no reporter knows any more about the accident than any other reporter, then no reporter can scoop all of the other reporters."

The statement "some reporter can scoop all of the other reports" is the negation of "no reporter can scoop all of the other reporters."

Hope that helps! Please let us know if you have any other questions.