PT 54: Section 2, LR, #19 Question Dicussion

secretad
Posts: 209
Joined: Tue Jan 04, 2011 11:26 pm

PT 54: Section 2, LR, #19 Question Dicussion

Postby secretad » Sun May 29, 2011 8:11 pm

This is the problem with the Eagles coach and his use a computer analysis.

You can diagram a part of this stimulus as:

Lose ---> ~ J Playing

Conclusion:

J Playing ---> ~ Lose

I agree that the flaw of this argument is a temporal issue of what has been true in the past will continue to do so without justification.

However, on the Manhattan forums, an instructor said that answer choice (A) would have been correct if the word sufficient was instead necessary.

Isn't this simply a valid use the contrapositive above, but with a flawed interpretation of it stemming from the temporal issue cited?

How could that be seen as "infers from the fact that a certain factor is necessary for a result that the absence of that factor is sufficient for the opposite result."


Is that not what a contrapositive is? How would that be a flaw?

This stimulus does not seem to have any sufficient/necessary issue at all.

secretad
Posts: 209
Joined: Tue Jan 04, 2011 11:26 pm

Re: PT 54: Section 2, LR, #19 Question Dicussion

Postby secretad » Mon May 30, 2011 11:09 am

Bump

tomwatts
Posts: 1551
Joined: Wed Sep 16, 2009 12:01 am

Re: PT 54: Section 2, LR, #19 Question Dicussion

Postby tomwatts » Tue May 31, 2011 10:42 am

Well, if no one else will take this on...

You're right, as far as I can tell. A doesn't match the argument as it currently stands, and the way that you would have to change it to match is: infers from the fact that a certain factor has been necessary for a result in the past that the absence of that factor will be sufficient for the opposite result in the future. In that case, the necessary/sufficient bit is not the important part, but the past/future part is.

For example, let's say I fill in all the bubbles on an LSAT scantron. Then I determine that I get a bad score only when I fill in the wrong bubbles (i.e. bad score -> wrong bubbles, the wrong bubbles being necessary for the bad score). Next time, I decide I'm going to fill in all the right bubbles instead, and I conclude I won't get a bad score anymore (i.e. ~wrong bubbles -> ~bad score). This is actually a valid argument, and it has the structure in discussion.




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