Prep test 25 - question 18 sectioin IV

[lipslikesugar]

" Obviously, we cannot in any real sense mistreat plants. Plants do not have nervous system, and having a nervous system is necessary to experience pain."

Ok. I found two good answers (B and D)
B- (only organisms that have nervous systems can experience pain)
D- (only organisms that experience pain can be mistreated).

My choice was B. I was wrong.
Why is D a better choice?
Any thoughts?

 
Thank you!

[ssilver0210]

We're told in the argument, that a nervous system is necessary for experiencing pain, so that is not an assumption (an unstated premise) on which the argument depends.

In the passage, we're told that we cannot mistreat plants. The reason why we cannot mistreat plants is because plants do not experience pain.

Let's say there were organisms that did not experience pain, but still could be mistreated. (The negation of choice "D")  If there were organisms that did not experience pain but still could be mistreated, then it's no longer true that we can not mistreat plants simply because they do not experience pain. (The conclusion of the  passage). A plant might be an organism that does not experience pain, but could still be mistreated.

In other words, for it to be true that we cannot mistreat plants simply because they do not experience pain, it also must be true that only organisms that experience pain can be mistreated.

[eslite119]

This is justify the conclusion, and the correct answer choice should SUFFICIENTLY allow the conclusion to be properly drawn in conncetion with the premises given in the stimulus.  The conclusion is, "We cannot in any real sense mistreat plants."  You need to justify this conclusion using the premise given.  

Diagram:

Premise 1:  Plants do not have nervous system.

Plants -> ~NS (Nervous System)

Premise 2:  Having a nervous system is necessary to experience pain.

Pain -> NS

Conclusion: We cannot in any real sense mistreat plants.

Plants -> ~Mistreat

Based on the premises given and looking at the conclusion, you'll note that there is a "jump."  Something is missing and just with the information within the stimulus alone will not allow one to arrive at the conclusion that "Plant cannot be mistreated."  

Try connecting premise 1 and 2 by using the contrapositive for premise 2:

Premise 2 contrapositive: ~NS -> ~Pain

Connect premise 2 and 1: Plants -> ~NS -> ~Pain

Looking at answer choice D, it says "Only organisms that can experience pain can be mistreated."

D:  Mistreat -> Pain

Contrapositive: ~Pain -> ~Mistreat

Connect this contrapositive to the premise 1 and 2, and you get:

Plants -> ~NS -> ~Pain -> ~Mistreat

Or by transitive property:

Plants -> ~Mistreat (OUR CONCLUSION)

Note that choice D includes ALL ORGANISM, which is not necessary for us to reach the conclusion, but it is SUFFICIENT for us to reach the conclusion noted in the stimulus.  On the side note, other choice like "Only organisms with nervous system can be mistreated" can also work.

Choice B is incorrect since it's somewhat of a repeat of premise 2.  We needed something to bridge the jump between the premises and conclusion.  Hope this helps.

[hopeful1985]

We're told in the argument, that a nervous system is necessary for experiencing pain, so that is not an assumption (an unstated premise) on which the argument depends.

In the passage, we're told that we cannot mistreat plants. The reason why we cannot mistreat plants is because plants do not experience pain.

Let's say there were organisms that did not experience pain, but still could be mistreated. (The negation of choice "D")  If there were organisms that did not experience plain but still could be mistreated, then it's no longer true that we can not mistreat plants simply because they do not experience pain. (The conclusion of the  passage). A plant might be an organism that does not experience pain, but could still be mistreated.

In other words, for it to be true that we cannot mistreat plants simply because they do not experience pain, it also must be true that only organisms that experience pain can be mistreated.

so you can use the assumption negation technique on the AC's for justify questions? how would it be applied- the same way as assumption questions? you just look for the AC  negated that would destroy the concl?

[lipslikesugar]

We're told in the argument, that a nervous system is necessary for experiencing pain, so that is not an assumption (an unstated premise) on which the argument depends.

In the passage, we're told that we cannot mistreat plants. The reason why we cannot mistreat plants is because plants do not experience pain.

Let's say there were organisms that did not experience pain, but still could be mistreated. (The negation of choice "D")  If there were organisms that did not experience plain but still could be mistreated, then it's no longer true that we can not mistreat plants simply because they do not experience pain. (The conclusion of the  passage). A plant might be an organism that does not experience pain, but could still be mistreated.

In other words, for it to be true that we cannot mistreat plants simply because they do not experience pain, it also must be true that only organisms that experience pain can be mistreated.

Got it.
Thank you so much

[KaplanLSATInstructor]

Forget the Denial Test on this one. Stick with the real issue:

According to the argument, a plant has no nervous system. Then, it tells us that a nervous system is necessary to experience pain. In Formal Logic, that means:

If an organism experiences pain, then is has a nervous system.
Contrapositive: If it doesn't have a nervous system, it can't experience pain.

By that logic, since a plant has no nervous system, it can't experience pain.

The real question is, where does "mistreatment" come from? We know plants can't experience pain, but why does that mean it can't be mistreated? We have to make a connection between pain and mistreatment. (D) fits the bill: If an organism can't experience pain, then it can't be mistreated.

(B) simply restates the formal logic of the argument, but doesn't connect any of the premises to the concept of "mistreatment" in the conclusion. Therefore, it's not an assumption nor does it justify or add any value to the argument.

- Chris

[lipslikesugar]

This is justify the conclusion, and the correct answer choice should SUFFICIENTLY allow the conclusion to be properly drawn in conncetion with the premises given in the stimulus.  The conclusion is, "We cannot in any real sense mistreat plants."  You need to justify this conclusion using the premise given.  

Diagram:

Premise 1:  Plants do not have nervous system.

Plants -> ~NS (Nervous System)

Premise 2:  Having a nervous system is necessary to experience pain.

Pain -> NS

Conclusion: We cannot in any real sense mistreat plants.

Plants -> ~Mistreat

Based on the premises given and looking at the conclusion, you'll note that there is a "jump."  Something is missing and just with the information within the stimulus alone will not allow one to arrive at the conclusion that "Plant cannot be mistreated."  

Try connecting premise 1 and 2 by using the contrapositive for premise 2:

Premise 2 contrapositive: ~NS -> ~Pain

Connect premise 2 and 1: Plants -> ~NS -> ~Pain

Looking at answer choice D, it says "Only organisms that can experience pain can be mistreated."

D:  Mistreat -> Pain

Contrapositive: ~Pain -> ~Mistreat

Connect this contrapositive to the premise 1 and 2, and you get:

Plants -> ~NS -> ~Pain -> ~Mistreat

Or by transitive property:

Plants -> ~Mistreat (OUR CONCLUSION)

Note that choice D includes ALL ORGANISM, which is not necessary for us to reach the conclusion, but it is SUFFICIENT for us to reach the conclusion noted in the stimulus.  On the side note, other choice like "Only organisms with nervous system can be mistreated" can also work.

Choice B is incorrect since it's somewhat of a repeat of premise 2.  We needed something to bridge the jump between the premises and conclusion.  Hope this helps.

Thank you