The passage starts by stating that only a minority of those who engage in political action do so out of a sense of social justice. There is a reason LSAC has used the phrase "only a minority." They want to get you to think about what the majority is doing. Therefore, if the minority of people who engage in political action do so out of a sense of social justice, then the majority of people who engage in political action do not do it out of a sense of social justice. Then it concludes from this that some people who have a sense of social justice do not engage in political action. What the conclusion of the passage does is switch and negate the variables. Sounds like a contrapositive, right? Well, we know that quantity statements do not have contrapositives. Therefore, if the principle statement is:
EPA-most-not SSJ
All we can do is switch it to be:
not SSJ-some-EPA
Answer choice (A) has the principle rule: Most scholars are not motivated by a desire to win prestigious academic prizes:
S-most-not WAP
The conclusion in answer choice (A) again tries to make the contrapositive of the principle rule by switching and negating the principle rule to be: Some people who do want to win prestigious academic prizes are not scholars:
WAP-some-not S
Again, quantity statements don't have contrapositives. All we can conclude from the principle rule in answer choice (A): "S-most-not WAP" is "not WAP-some-S" because you can switch the variables of a MOST statement to a SOME statement.
The flaw in both answer choice (A) and the stimulus is that a contrapositive is being concluded when quantity statements cannot have contrapositives.
Hope that helps! Please let us know if you have any other questions.
AdvaithAugust 13, 2015
Very helpful
MarieNovember 30, 2017
I understand you explanation and I appreciate your explanation. I have just got one further question for you just to clarity please:
I know and understand that they are assuming that there is a contrapostive when you can't make a valid constrapositive of the question. However, in the stem they are "changing" different parts of the statement into the contrapostive. for example in the stem it goes from:
PA - most- not SJ
SJ - some- PA
and in A its
S-most not WP
WP - some - not S
They are trying to use a contra-postive but they are using it one different parts of the statement (for the want of better terms sorry).
so it is enough that they tried to do a contra postive it doesn't have to be exactly the same parts of the statement that is changed in the contra-postive, right?
