#19 - Editorialist: Some people argue that we have an

[Administrator]

Complete Question Explanation

Assumption-SN. The correct answer choice is (D)

This is a seemingly confusing argument, which is why it would benefit immensely from a good conditional reasoning diagram:

• OBL = obligations
  
  R = rights
  
  OBLT = obligations towards trees
  
  RT = rights of trees
  
  Premise: OBL R (we have no obligations to an entity unless it has rights)
  
  Premise: OBLT RT (if we have obligations towards trees, trees have rights)
  
  Premise: RT (trees have no rights)
  
  ======================
  
  Conclusion: OBL (we have no obligation not to cut down trees)

Do you see the gap in this reasoning? As present, the premises only give rise to a conclusion that states we have no obligation towards trees (OBLT). The author, however, goes a step further, arguing that we have no obligation not to cut down trees. The two may seem similar, but they are not — which is why close reading is of paramount importance on the LSAT. Just because we have no obligation towards trees does not mean that we have a carte blanche to cut them down. Maybe we owe the obligation of not cutting them down to animals or people, both of whom might have rights. In other words, the argument assumes that the obligation not to cut down trees can only be owed to trees alone:

• OBLT → OBL

Answer choice (A): Since trees have no rights (this is a given), this answer choice is irrelevant and unnecessary for the conclusion to be true.

Answer choice (B): This is the Mistaken Reversal of a central premise of the argument. Since trees have no rights (this is a given), this answer choice is irrelevant and unnecessary for the conclusion to be true.

Answer choice (C): This may seem like an attractive answer at first, since trees are not conscious entities and have no rights. However, that trees have no rights is a given — you need not provide additional support for the premises used in the argument. Even if some unconscious entities had rights, it is still a given that trees do not.

Answer choice (D): This is the correct answer choice. If we owed an obligation not to cut down trees to some other entity, the author's conclusion would be seriously weakened.

Answer choice (E): Cutting down the trees on someone's property and the corresponding right to do so are both irrelevant considerations and unnecessary for the conclusion to be true.

[voodoochild]

Instructors,
My mind went for a toss after reading this problem. Can you please help?

st1 : Some people argue that....<ignore -> someone else's point>

St2 : ~Right => ~Obligation

st3 : restatement of st2; doesn't help

st4 : tree => ~Rights

st2 and st4 : tree => ~Obligation ...Or We have no obligation to tree.

Conclusion : (Restatement) - We have obligation to cut trees. (Conditional world: we are required to cut trees OR tree => cut them)

<CRASH> Can someone please help me? I don't know how the necessary assumption fills the "necessary" gap...Please help

Thanks
Voodoo

[Adam Tyson]

I think you're on the right track, voodoo, but perhaps missing a key point here. We start off with the classic "some people say" argument structure - some people say X, some people believe Y, etc. As is typical for LR questions that start this way, the author proceeds to his conclusion, which is some variation on "those people are wrong". Also fairly typical is that the author has a flaw in his reasoning - that doesn't always happen, but it happens a lot. Everything else, besides the thing that people say and the conclusion that they are wrong, is a series of premises to support the conclusion that those folks are wrong.

Let's look at your diagram, starting with the first premise, which is an "unless" statement that triggers our "unless equation". Here, unless introduces the concept of rights, so that's our necessary condition. The other condition, no obligation, gets negated and becomes obligation. The correct diagram, then, is O(bligation) -> R(ight). That of course proves the contrapositive, which is what you diagrammed.

The next statement is the one you wanted to discard as a useless restatement of the first premise, but it's actually important. The author takes the general principle from his first premise (O -> R) and applies it to something concrete - trees. Otrees -> Rtrees. Follow that with our third statement, which is essentially that trees cannot have rights. In other words, looking at the previous conditional argument, the necessary condition cannot happen. From there he concludes the contrapositive - Rtrees -> Otrees. That's pretty much what you have as your last two statements.

Here's where your diagram goes off the rails: you concluded, based on the argument, that if there is no obligation to trees (or that there is no obligation not to cut trees) that there IS an obligation TO cut them. That's not warranted. You've made your own flaw in the reasoning there - a false dilemma. Is there another possibility besides being obligated to cut trees or else being obligated not to cut trees? Perhaps the third alternative is that there is no obligation of any kind?

That's not our author's flaw, though. Remember, he started with the statement that some people believe we have an obligation not to cut trees, and he concluded that belief was wrong because we cannot be obligated TO trees. What if the obligation is not to the trees, but to someone or something else? What if the obligation is to the animals that live in or otherwise depend on the trees? What if the obligation is to future generations of humans, who will need the trees to keep the air clean and to generate oxygen? If animals or humans can have rights, then we can have an obligation to them.

Here's another way to look at it: what if the argument was that some people believe we have an obligation not to poison the water supply, but those people are wrong because water has no rights? You were looking for a conditional flaw, I think, but even though there was plenty of conditional reasoning in the argument, the flaw was not conditional (not a mistaken reversal or mistaken negation), but rather a flawed assumption in the application of the conditional rule.

Don't crash! Sometimes the best approach is to let go of the mechanical application of the strategies, such as for conditional reasoning, and take a more holistic approach, looking at the argument as a whole and asking yourself "what's wrong here?" Would you accept this argument as valid on its face, or would you question it? How would you poke a hole in it, if you and this author were engaged in a debate? Mastering the techniques is important, but so is mastering when to step back and allow your own grasp of the logic to guide you. Get the techniques down first, and then you'll be better equipped to decide when to use them and when to try another approach.

I hope that helped.

Adam M. Tyson
PowerScore LSAT Instructor

[voodoochild]

Adam,
Thanks for your detailed reply. I read your response at least 10-15 times just to make sure that I absorb every word in it. I have three questions.

So the argument says that : Premise : There is no obligation to trees.

Conclusion - There is no obligation not to cut trees.

The gap is between "trees" and "not to cut trees"...The author mistakes "no obligation to trees" for "no obligation not to cut trees." We might have an obligation to some other entities, in which case the argument will be weakened.

Question#1:
Let me construct a parallel argument so that things are clear in my mind. (In fact, I really like this approach recommended in your book - It helps us to connect dots in our mind.)

Premise - I don't have an obligation to buy a car.
Conclusion - I don't have an obligation to buy a car for my dad.

Assumption - Not buying a car is not an obligation to my mom.
[I am actually not 100% sure. My head goes for a spin after reading such double/triple negatives.]

Question#2 : Conclusion says that 'there is no obligation not to cut down trees.'
Can I translate this to say that "there is an obligation to cut down trees" or "we must cut trees" --Please let me know.

Question#3: the correct answer choice also uses double negative ...."avoiding cutting down trees is not an obligation owed to some other entity other than trees"
Can I translate this as (just trying to test my conditional diagramming skills) :

"not cutting down trees is not an obligation owed to some entity other than trees"

OR


~(cutting down trees) ~(obligation to some entity other than trees"

OR
(take the contra+ve)
obligation to some entity other than trees cut down trees.

OR - If there is an obligation to some other entities then cut down trees. (this doesn't sound correct to me. Not sure....I tried this for 20-30 minutes...Please help me )

Thanks again for your help.

[Adam Tyson]

First, as to the parallel argument you propose, I think we are starting off on the wrong idea. The premise is not that there is no obligation to trees - it's that there is no obligation to things that don't have rights. There's a second premise, and that is that trees don't have rights. That's why we get the conclusion that there is no obligation to trees.

Next, I would absolutely not say that no obligation not to cut trees is the same as an obligation to cut trees. That's applying the old double-negative rule improperly. The only thing that gets negated is the idea of "obligation" - there either is an obligation or there is not an obligation. Your application means that there is always an obligation - to either do something or to not do something - and that flies in the face of the premise that there can only be an obligation to something if that thing has rights.

Same problem with the third question you posed - don't negate "not cut trees" and turn it into "cut trees". The only thing you should be negating when you take the contrapositive is the idea of "obligation". Negate that answer choice and you get "avoiding cutting down trees is an obligation to some entity other than trees". That's the one that destroys the author's conclusion.

Adam

[voodoochild]

Adam,
Thanks for your detailed reply. Now, after reading and re-reading your response for a few days, I think that I have understood the issue.

I have tried to come up with a parallel argument to test my understanding. Please let me know whether it's correct


Question#1:
Counter Claim - We have an obligation to buy a present for our friends.

Premise1 - We have an obligation toward our friend, if they have right.
Premise2 - Friends don't have right.

Premise1 + Premise2 = We don't have an obligation toward our friend.
(author's faulty Conclusion) - I don't have an obligation to buy a present for my friend.

The assumption is that not buying a present for our friend is not an obligation to a person other than my friend. (I could have an obligation to my friend's dad, who could be my teacher)

Question#2

I see your point about negation. I think that there are two parts to the double negation: a verb negation and noun negation.

For instance, if I say that the court has not recommended that adults not eat cookies. It doesn't mean that the court has recommended that adults eat cookies. I cannot bump "not" attached to "recommended" and add it to another verb "eat." However, if I am given that the court has hardly recommended that adults not eat cookies, then I can say that the court has not recommended that adults not eat cookies. Here, "hardly" is modifying the past tense verb "recommended."

Similarly, there is no obligation to not tease girls doesn't mean that there is an obligation to tease girls. haha. I cannot bump up noun-negation (no obligation) wiht verb-negation (not tease).

Is my understanding correct? Do you know any other LSAT question that deals with such multiple negations? Please let me know. I went through you book yesterday, and I couldn't find anything substantial. Please help me

[Adam Tyson]

I think you've got it! Good job. Now don't worry too much about this one - the tricky multiple-negation issue here is unlikely to play a major role in your test, and if it does come up, you'll recognize it and know what to do.

Adam

[Applesaid]

hello!

I am having a trouble with the correct answer choice itself because it looks opposite against the idea I gain from the stimulus.

The stimulus says that

If we have obligation to an entity, that entity must have a right. Thus if we have obligation to trees, then trees must have rights. But since trees do not have rights, we then have no obligation toward trees (not to cut down trees).

But answer choice D looks strange for me. The stimulus itself doesn't seem to have logical gaps so would this answer choice work to eliminate other alternative entities that might have rights?

[Jacques Lamothe]

Hey Applesaid,

In this case, you are looking for an answer choice that functions as an assumption in the argument. But remember, assumptions can be either supporter assumptions or defender assumptions. If the connection between the premises and the conclusion looks good to you, then the argument amy not require any supporter assumptions that link premises to conclusions. However, it may still rely on defender assumptions that eliminate other ideas that could undermine the conclusion.

In this question, answer choice D is a necessary defender assumption. Pay close attention to the shift in language between the premises and the conclusion.The author's premises indicate that we can not have an obligation to a tree. But the conclusion is that we have no obligations at all to refrain from cutting down trees. Imagine that I am sitting in the fall path of a tree and I will be hit if you continue to cut down the tree. Even if you have no obligation to the tree, you could have an obligation not to hurt me that would obligate you to not cut down the tree. This is the type of situation that answer choice D excludes. The author's conclusion that we have no obligations to refrain from cutting down trees is only validly drawn from the conclusions if we assume that there are also no obligations to entities other than the tree that would obligate us to refrain from cutting down the tree.

I hope this clears some things up!

Jacques

[vas]

Hello,

I see that the premises only give rise to the conclusion that we have "no obligation towards trees" but the author goes one step further by concluding "we have no obligation not to cut down trees." I'm having trouble understanding what the "no obligation not to cut down trees" actually means in the argument. Could you provide an explanation? It somewhat clicked when I read the answer explanation, but an alternative explanation would help too.

Thanks!