"Since" introduces a premise. Our general principle (the first sentence) is what is introducing the sufficient and necessary. The general principle: If you are able to meet the company's selling quota, then you are an experienced salesperson. A general principle means nothing without a premise. "Since" introduces our premise: I will be able to sell only half the quota. The speaker then uses that information to conclude from the general principle that he or she is not an experienced salesperson. The "only" in the passage introduces the sufficient and necessary general principle. The "since" merely introduces the premise i.e. the existence of the necessary condition. The flaw in the argument is that the speaker is using the existence of the necessary condition of the contrapositive: not meeting the company's quota, to conclude the sufficient condition in the contrapositive: not being an experienced salesperson. However, one can be an experienced salesperson and not have met the company's quota. We must always remember to reverse and negate when making a contrapositive, not just negate. Hope that helps!
SelinaJanuary 16, 2015
How would I graph this?
NazJanuary 16, 2015
"Only experienced salespeople will be able to meet the company's selling quota."
P1: MCQ ==> ES not ES ==> not MCQ
"since I will be able to sell only half the quota."
P2: not MCQ
"Thus, I must not count as an experienced salesperson,"
C: not ES
(B): "Only music lovers take this class. Thus, since Hillary is not taking this class, she apparently does not love music."
P1: TTC ==> ML not ML ==> not TTC
"since Hillary is not taking this class,"
P2: not TTC
"she apparently does not love music."
C: not ML
Hope that was helpful! Please let us know if you have any other questions.
