"sufficient" and "necessary" placement - L. 2 Virtual Course

[rachue]

Hi all,

I've read over lesson 2 and it's definitely making me feel stupid because I can't get the placements right for what is supposed to be in the "sufficient" part and what is in the "necessary" part. I oftentimes reverse them.

Can someone let me know if it really matters? Sometimes I put them in the opposite positions than powerscore does but I end up getting the correct answers.

For example, question 5 in the lesson 2 hw:

"Politician: It is wrong for the gov't to restrict the liberty of indviduals, except perhaps in those cases when to fail to do so would allow individuals to cause harm. Yet, to publish something is a liberty , and to offend is not to cause harm."

I set up my formula as : cases where harm would be allowed→ ok to restrict liberty

I got the correct answer with this formulation, but powerscore explained that the formulation should have been the exact opposite! ie:

ok to restrict liberty → cases where harm would be allowed

I think I'm just making it more complicated than it really is, but I can't seem to internalize the system that powerscore uses.

Can someone please explain this to me? For some reason I'm not getting it even after going through the lesson again...

[Jon Denning]

Thanks for the questions. First off, it is EXTREMELY important that you not reverse the terms. In the course we call that a Mistaken Reversal, and it's the most common error/trap that the test makers try to exploit.

Since you're in the course, I strongly encourage you to take advantage of the Lesson 2 conceptual recap that is in the online student center. It offers a comprehensive breakdown of conditional reasoning and will provide a much better analysis than I could type out here. If that, along with some more practice, doesn't resolve any issues let us know here and we'll keep working with you until you get it.

**As an aside, keep in mind that every single concept discussed in each lesson is followed by a detailed, instructor-led review in the student center, so if you're ever struggling with anything from the course you've always got additional resources to help you out!

[rachue]

Ok many thanks! I will check it out!