Q23 - Ecologist: Without the intervention of

[mshinners]

Question Type:
Inference (Must be True)

Stimulus Breakdown:
-Intervention → Extinct
Preserved Forest → Survive
Squirrel monkeys like this type of Forest for reasons.

Answer Anticipation:
First off, it's important to note that we can change the necessary conditions of the conditionals to overlap. If something survived, it didn't go extinct; if something is extinct, it didn't survive. Rephrased and contraposed, we get:
Preserved Forest → Survived → Intervention

We should expect the correct answer to be this or the contrapositive. The last statement is ... great, but when there's a mix of conditionals and non-conditionals in a Must be True question, the non-conditional statements are usually just there as a distraction.

Correct Answer:
(E)

Answer Choice Analysis:
(A) Degree/out of scope. While squirrel monkeys flourish in these habitats, and they'll survive if these forests are preserved, the argument doesn't treat these habitats as necessary for squirrel monkey survival (check the chain - the forests are sufficient, not necessary).

(B) Detail creep/degree. First, this answer choice is causal ("will do so by…"), and the givens are conditional. Conditional statements don't guarantee causality. Second, conditional statements also only tell us something will happen when a triggering event occurs. This answer choice treats it as certain that conservationists will intervene, which we don't know for sure.

(C) Illegal negation. The stimulus gives us enough information to infer that if the monkeys go extinct, the forests were not preserved. That doesn’t allow us to infer that the forests not being preserved guarantees they'll go extinct. This answer choice also makes a jump in assuming that if the forests aren't preserved, the monkeys can't get a plentiful supply of their favorite insects and fruit.

(D) Illegal reversal. The conditionals tell us that if the monkeys survive, there was an intervention. This answer choice illegally reverses that.

(E) -Intervention → -Preserved Forest
This answer is the contrapositive of our chain, making it a valid inference.

Takeaway/Pattern:
1) "Without" = "If not" in conditional parlance.
2) Be sure to not jump between conditional statements and causal statements - they're not the same thing.

#officialexplanation

[pwleed]

The answer is E, and I presume that this is due to formal logic. I was waffling between answers and eventually picked C.

Does the correct pattern of formal logic go:

No Intervention -> Extinct
Not Extinct -> Intervention

Second-Growth Forest -> Survive (Not Extinct)
Not Survive (Extinct) -> No Second Growth Forest

So

No Intervention -> Extinct -> No Second Growth Forest

?

[aileenann]

Yes, that is perfect. Good work.

[bnuvincent]

If No Intervention -> Extinct -> No Second Growth Forest

is the case ,then it can be stated like

Second Growth Forest -> Intervention ,
and the some clause can be get like

some Growth Forest -> some Intervention
and
some Intervention -> some Growth Forest.

This is the B choice, so could you please explain?

[aileenann]

Thanks for your follow up question!

I think you got a little bit off the right track when you moved from:

Second Growth Forest -> Intervention

to


some Growth Forest -> some Intervention

I don't see any "some" language in the argument - in fact the whole reason you can write this argument translated into formal conditional statements is that these statements are always true - they don't break down into some kind of sometimes or some part sort of structure.

You may have thought you could take something like larger tracts, and turn them into "some" tracts, but these aren't quite the same thing.

Does that make sense? Please let me know if you have more questions

[linzru86]

Isn't the large tracts of second growth forest habitat not a necessary condition? It is one possible way but the conservationists don't HAVE to help preserve these forests to ensure the survival of the monkeys, but they do have to intervene in some way. So I chose B because perhaps some conservationists will do so, since it obviously helps their survival, but E makes it seem like saving the forests is a necessary thing the conservationists need to do and I thought that was exaggerated. What am I missing here?

[farhadshekib]

Isn't the large tracts of second growth forest habitat not a necessary condition? It is one possible way but the conservationists don't HAVE to help preserve these forests to ensure the survival of the monkeys, but they do have to intervene in some way. So I chose B because perhaps some conservationists will do so, since it obviously helps their survival, but E makes it seem like saving the forests is a necessary thing the conservationists need to do and I thought that was exaggerated. What am I missing here?

Hey I choose (B) for the same reason. But (E) is correct.

SME: Squirrel Monkey Extinct
CI: conservationist Intervention
LTFP: Large tracts of second growth forest habitat preserved

We can diagram the statements like this:

Fact 1 - Without intervention of C, SM will go extinct.

~SME --> CI

Which ever word is modified by except, until, without, or unless become the necessary condition, the remaining is negated and becomes the sufficient condition.

In this question, the intervention of the conservationist becomes the necessary condition, and the extinction of the squirrel monkeys is negated (so they won't become extinct) and becomes the sufficient condition.

Fact 2: SM survive if large tracts of second growth forest habitat are preserved.

LTFP --> ~SME

Combine 1 and 2:

LTFP --> ~SME --> CI

Inference:

LTFP --> CI.

That is, if the large tracts of second growth forest habitat are preserved, then the conservationist will intervene.

Note, though, that the stim does not say how the conservationist will intervene.

(E) states: ~CI --> ~LTFP

In other words: if the conservationist don't intervene, large tracts of the second growth forest habitat will not be preserved for the squirrel monkeys.

(B) is wrong because, again, we cannot infer how the conservationist will intervene.

P.S. I hate the LSAT.

[trevor.lovell]

I answered B, in part b/c it was question #23 and I was short on time so selected B before reading the other answers. Looking back at it with more time I'm not sure it would have helped anyway.

I wanted to simplify this back down for myself and others, so here's what I came up with (which is very similar but maybe just a little quicker than the first post on this question),

S = monkeys Survive
P = tracts of forest Preserved
C = Conservationists intervene

Not C --> Not S
P --> S
therefore
Not C --> Not P
(b/c P would lead to S which cannot coexist w/ Not C)

Answer E basically says Not C--> Not P.

To answer a question posed above, this does not mean the conservationists will preserve the forest (answer B). It just means that without their intervention the forest will not be preserved.

To take this logic out into a real-world scenario, you could imagine conservationists simply raising awareness of the plight of the squirrel monkey but not themselves preserving any forest. In this scenario we would assume based on the stimulus that without this intervention nobody would have known and the forest would have been destroyed. But raising this awareness could result in forest being preserved b/c some 3rd party decided to act (a government creates a preserve, a land trust purchases forest tracts, etc.)

[joseph.m.kirby]

The logic of the stimulus goes like this:

~intervention --> extinct --> ~large tract 2nd growth forests

(E) says ~intervention --> ~large tract 2nd growth forests

(B) says conservationists & intervene -(some)-> will use large tract 2nd growth forests

The logic of the stimulus does not support (B). The stimulus tells us:

~intervention --> ~large tract 2nd growth forests

-or-

large tract 2nd growth forests --> intervention

Consequently, intervention is a necessary condition. If the conversationists intervene, they DON'T have to use "large tract 2nd growth forests." They could use some other means to help the monkeys. In other words, intervention is NOT SUFFICIENT for large tract 2nd growth forests (it does not require "large tract 2nd growth forests" to occur).

[tzyc]

I understand how (E) is correct, but how about (C)...?
Since it says SM flourish in second growth forest because of the plentiful supply of their favorite insects and fruits.
Or is it because it's not conditional statement and flourish and extinct are different things?

Thank you

[sumukh09]

I understand how (E) is correct, but how about (C)...?
Since it says SM flourish in second growth forest because of the plentiful supply of their favorite insects and fruits.
Or is it because it's not conditional statement and flourish and extinct are different things?

Thank you

Remember for this argument there's two ways of preventing extinction of the squirrel monkeys. One of them is if conservationists intervene and the second is if large tracts are preserved for them. This is an inference question so we're asked for something that must be true.

C doesn't have to be true; they get plentiful supplies of their favourite insects and fruits if the large tracts of second growth forests are preserved for them. But does that mean they would be extinct if they didn't get these tracts of land preserved for them? No, because conservationists could still intervene and keep them from becoming extinct.

Also the conditional logic that C is suggesting is all kinds of messed up. C says ~ supply of fav food --> Extinct

But the logic in the stim is:

Tracts of land preserved ---> ~Extinct

Nowhere is there any conditional logic with respect to their having plentiful supply of insects and fruit.

[nflamel69]

The way you said it implies conservationist effort is sufficient to prevent extinction. However, the stimulus simply said it is necessary. The reason B is wrong because it wrongfully connect conservationist effort and preserving the forest. While it is reasonable to infer that preserving the forest requires their efforts, you cannot conclude that their effort to help the monkeys and how they can do it ( will do so by preserving the forest).

[dean.won]

Is B wrong because preserving 2nd forests is not necessarily the only way to preserve forests?

I think this was farhads reasoning as well... but not entirely sure

[amil91]

Is B wrong because preserving 2nd forests is not necessarily the only way to preserve forests?

I think this was farhads reasoning as well... but not entirely sure

I think anyone that was tempted by (B) for this question misunderstood what your task was. This question is an inference question, the answer MUST be TRUE give the statements in the stim. For ex. If A then B and If B then C. From that what can we infer? If A then C, simple logic chain. Answer choice (B) cannot be inferred at all from the stim, we don't know if any of the conservationists intervene nor do we know how they would intervene. All we know is that if the monkeys did survive it must have be the case that the conservationists did intervene and that if large tracts of second-growth forest are preserved then the monkeys will survive, but this gives us no information regarding conservationists actually intervening, nor does it give us information regarding how any conservationists will choose to intervene if they did choose to intervene.

For me this question does not need to be broken down into formal conditional logic to be answered correctly. POE works very well for this problem and works much quicker, for me, than does putting it into formal logic:
(A) can be eliminated as no other habits are discussed, so how could we infer anything about them?
(B) can be eliminated for reasons stated above, that for me, can easily be seen without breaking this down into formal logic. I would always be weary of an answer choice that is declaratory when the stimulus is entirely conditional on an inference question.
(C) is tougher to eliminate than A and B, but a quick look back to the stim shows that the text of (C) - 'plentiful supplies of their favorite insects and fruit' is simply an explanation for one of the conditional statements, it in itself is not conditional.
(D) is the only one, in my opinion, that may require breaking down the first statement into formal conditional logic, but if you are fairly comfortable with conditional logic then you should be able to quickly see that (D) is a reversal of the first statement and thus invalid (we only know what happens in conservationists don't intervene or what happens if monkeys do survive).

[yisiyu123]

I think to eliminate B we must distinguish a plain FACT from an CAUSAL LINK
The ecologist was just making separate claim that without something what would happen to monkeys, they do not actually correlate with each other

Let's simplify the argument into the following

Without John Doe doing something to the monkeys, the monkeys will die, and monkeys will survive if there is enough food for it.
We can say without John Doe doing something, food will not be given to the monkey b/c if food was provided the monkey will survive(that's E)
But we cannot say that there must be a possibility that John Doe helps the monkeys survive by providing it food.(that's B)
Does it make sense?

Let me put it this way
B, saying that "at least some conservationists" will help survive by preserving the habitat, assumed that there cannot be a possibility that none of the conservationists helps the monkeys survive by preserving second-growth forest habitat
But that can definitely be the case. There IS a possibility that none of the conservationists help monkeys survive by preserving habitat

Therefore, B cannot be properly inferred.

[zdlsat]

I also have some question about C. I think you are wrong here.
This first sentence shows that:
~IC(intervention of conservationists) ----> E(extinct)
~E------> IC

Second sentence shows that :
FHP(forest habitat preserved)---->~E(survive)
E------>~FHP

so, actually there only one way lead to ~E(survive), that is FHP. IC is required, but IC is not sufficient to ~E.
Third sentence explain why. Because plentiful supply, monkey could flourish.
I remember I read an article where an LSAT geek explained that BECAUSE is kinda like indicating a causal relation. In other words, Supply causes Flourish( ~E, survive)
We know that, in a causal relation, no cause, no effect,
so, ~S ----> ~F ( E, ~survive)

That it what answer C is saying.


Can anyone point out where I am wrong?

Thank you ahead.

[ohthatpatrick]

You don't wanna convert causality into conditional logic, unless they're throwing conditional logic triggers at you.

"Because" does indicate a causal influence. But it does not indicate a sufficient or a necessary causal influence.

I got that A because I studied

Does that mean
no Study, no A?

No. Studying was involved in the causal story of how I got my A, but if I hadn't studied then maybe I would have cheated my way to an A, or some other causal story.

Does it mean
if Study, then A?

No. Again, maybe studying had an influence, but maybe so did my innate intellectual capacity as well as the fact that I hired a tutor to help me.

Had I just studied but not had the tutor, I might not have gotten the A.

What "I got an A because I studied" allows us to say is, "Patrick's grade was not exclusively the result of luck".

=====

As to (C) on this question ... who said that squirrel monkeys need to live in second-growth forests? Even if you did interpret the final sentence to mean that "without plentiful insects and fruit, squirrel monkeys would not flourish in second-growth forests", you still leave room for them to survive, but not flourish, in 2nd growth.

You leave room for them to survive and possibly flourish in 1st, 3rd, 4th growth forests. (I doubt that forests come in all those flavors, but you get my point)

The only way this info lets us prove that squirrel monkeys go extinct is
"Conservationists do not intervene".

[zdlsat]

Hi ohthatpatrick

Thank you so much for your clarification.
I made a mistake, confusing the way to strengthen a causal relation, which is " no cause, no effect"

Yes, "no cause, no effect" can only strengthen a causal argument, but I can't not convert it into a condition logic.

Thank you again! Your clarification is really helpful!!!!!

[ganbayou]

Hi,

I'm trying to understand the argument without using the conditional symbols since I am not sure I will have time to write them out.
I'm not sure between D and E.
For D, is it wrong because it does not necessary the monkeys will survive with the intervention of conservationists?
So even if there is intervention of conservationists, they may not provide large tracts of second-growth forest habitat?
For E, I thought it was wrong because I thought even without the intervention of conservationists, large tracts of second growth forest habitat can be preserved for the monkeys, maybe from other people. (This kind of related to D...I thought there can be other resources or people that can help them.)
Why is this thought wrong?

(I thought as a methaphor...
Eg.
Without mother, baby cannot survive.
But they will survive if there is plenty of food.
I thought E is wrong because maybe baby can have plenty of food from father.)


Thank you

[ohthatpatrick]

I applaud your desire to think through this one conceptually, but this is an example of where conditional logic is a superior tool. A lot of LSAT's conditionals don't really accord with common sense or any sort of everyday knowledge we have.

So you're having a hard time putting together an intuitive understanding. Your mother/father/baby analogy was great.

The problem is this --- would you ever say THIS in real life:
IF there is plenty of food, the children WILL survive. (Survival guaranteed!)

There's no great way to think about that one intuitively because we would never guarantee survival in real life.

Similarly, in this paragraph, having large tracts of 2nd growth forest GUARANTEES the survival of monkeys.

Cool, so all that matters to monkeys is having 2nd growth forest and all that matters to babies is having food. Those are enough to survive.

So it's weird to say "the monkeys' survival DEPENDS on conservationists" or "the baby's survival DEPENDS on the mother".

We'd think:
Why do conservationists or mothers matter so much? Maybe there are other forces that can provide 2nd growth forest or food.

The problem is that first restrictive rule precludes those sorts of possibility.

If a dad could provide food, and food is good enough to survive, then it would be impossible to say that "babies DEPEND on mothers for survival".

If someone else could provide 2nd growth forest, and 2nd growth forest guarantees survival, then it's silly to say "monkeys DEPEND on conservationists for survival".

When we are told that monkeys WILL DIE for sure unless conservationists intervene, that's telling us that "conservationists are the only ones who can provide that sweet, sweet 2nd growth forest".

If we're told that babies WILL DIE without their mother, that's telling us that "mothers are the only ones who can provide that sweet, sweet food."

That's about as good as I can do at making it intuitive. If we re-arranged ingredients we could make it flow better.

2nd growth forest is all monkeys need to survive.
Monkeys will die unless conservationists help them.
-------------------------
Monkeys need conservationists to help them get 2nd growth forest.