"As long as" - Formal Logic?

MissLucky
Posts: 903
Joined: Mon Sep 21, 2009 4:48 pm

"As long as" - Formal Logic?

Postby MissLucky » Fri Oct 01, 2010 4:18 pm

for example, the first line of Q23 in PT53 (section 3) states:

"A species can survive a change in environment, as long as the change is not too rapid."

translating this statement into some kind of Formal Logic was by no means necessary to this question (and i'm not even sure if it's possible), but I am curious as to what "as long as" signifies.

Would this sentence be properly represented as such:
If species survive a change in environment --> the change is not too rapid
OR
If the change is not too rapid --> species survive a change in environment

??

Thank you!

dakatz
Posts: 2460
Joined: Sat Mar 29, 2008 4:19 pm

Re: "As long as" - Formal Logic?

Postby dakatz » Fri Oct 01, 2010 4:20 pm

MissLucky wrote:for example, the first line of Q23 in PT53 (section 3) states:

"A species can survive a change in environment, as long as the change is not too rapid."

translating this statement into some kind of Formal Logic was by no means necessary to this question (and i'm not even sure if it's possible), but I am curious as to what "as long as" signifies.

Would this sentence be properly represented as such:
If species survive a change in environment --> the change is not too rapid
OR
If the change is not too rapid --> species survive a change in environment

??

Thank you!


The former of the 2. If a species survives a change in environment ---> the change is not too rapid

MissLucky
Posts: 903
Joined: Mon Sep 21, 2009 4:48 pm

Re: "As long as" - Formal Logic?

Postby MissLucky » Fri Oct 01, 2010 4:25 pm

nice - thanks!

cubswin
Posts: 618
Joined: Mon May 25, 2009 4:40 pm

Re: "As long as" - Formal Logic?

Postby cubswin » Fri Oct 01, 2010 4:37 pm

You've already been told the correct answer, but to explain it a little more, "as long as" should sound like a requirement or a necessary condition. Requirements always go on the right side of the arrow. Consider a simpler example:

"Jimmy can watch TV after dinner as long as he eats his vegetables."

Jimmy can watch TV after dinner ---> Jimmy ate his vegetables.

MissLucky
Posts: 903
Joined: Mon Sep 21, 2009 4:48 pm

Re: "As long as" - Formal Logic?

Postby MissLucky » Fri Oct 01, 2010 4:50 pm

okay, knowing what "as long as" indicates is actually making it more difficult to see (D) as fully parallel in Question 23 (obviously considering all the other answer choices it easily takes the cake, but this is for the sake of analysis).

The stimulus evidence says:
If a species can survive a change in environment --> the change is not too rapid
...and given this, it conclusion goes on to explain where the threat to survival comes from (i.e. goes on to explain the opposite of the SUFFICIENT clause)


And the correct parallel response was (D) where the evidence states:

If people know what change will bring --> people do not fear change
...and given this, its conclusion goes on to explain where the employees fear comes from (i.e. goes on to explain the opposite of the RESULT clause)

This evidence doesn't exactly seem parallel to me - thoughts? what am I missing?

thnx!




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