ltowns1 wrote:Pf 35 #17 section 4, PT 22 section 4 #19
Oh okay. I see what you mean now by attacking the necessary condition. This is an except question so there are a lot of assumptions/flaws in this argument. It is basically a lot of formal logic, so you can "attack" the necessary conditions, but you don't necessarily need to attack the conclusion (in this case, that only eliminates answer choice A)
The necessary condition of the conclusion says you can't tax at a higher rate than 30%, whereas answer choice (A) basically says that the real number should be 45% (and therefore it weakens the conclusion because you can in fact tax higher than 30%* and therefore directly contradicts the conclusion).
If you notice, the other AC's you eliminate do not have to do with the necessary condition in the conclusions so as a general rule of thumb, no you do not have to attack the necessary condition in the conclusion but it can be a tool in your toolbox so--as always--be very critical of the conclusion in relation to the support.
(E) is correct because it is irrelevant and therefore does nothing to the argument. Doing nothing is not the same as weakening.PT22S4Q19
Bingo. You're right. The correct answer attacks the "MUST act responsibly." Answer choice (B) finds a loophole and is therefore correct. There's also a subtle term shift from what society THINKS is responsible and the act of ACTUALLY ACTING responsible in the conclusion. If you picked up on that, you should have solved this very quickly.
I'm here to help, man. It's just hard to follow your threads sometimes. They tend to veer towards the bizarre, but maybe I'm just the kind of person who needs to be shown what you're actually talking about rather than told.
As a rule of thumb though, you don't need to always attack the necessary condition in the conclusion. In the PT35 question, only one of the 4 acceptable weaken AC's attacked the necessary assumption in the conclusion. The other three did not, so be flexible and don't always rely on attacking the necessary condition in the conclusion because while it works in the PT22 question, there will be other questions where you'll be left twiddling your thumbs if you strictly adhere to that rule.
*eta: fixed typo.