Critical Reasoning

In their native habit, amaryllis plants go dormant when the soil in which they are growing dries out during the dry season. Therefore, if amaryllis plants kept as houseplants are to thrive, water should be withheld from them during part of the year so that the plants go dormant.
Which one of the following is an assumption on which the argument depends?
(A) Most kinds of plants go dormant at some time or other during the year.
(B) Amaryllis are more difficult keep as houseplants than other kinds of plants are.
(C) Water should be withheld from amaryllis plants kept as houseplants during the exact time of year that corresponds to the dry season in their native habitat
(D) Any amaryllis plant that fails to thrive is likely to have been dormant for too short a time.
(E) Going dormant benefits amaryllis plants in their native habitat in some way other than simply preventing death during overly dry periods

dry --> dormant
------------
thrive --> dormant


What is missing: thrive --> dry


E is the answer

its between D and E.

I went with D, in E there isn't any mention that the benefits could actually help thrive the plants.

gmatmachoman wrote:In their native habit, amaryllis plants go dormant when the soil in which they are growing dries out during the dry season. Therefore, if amaryllis plants kept as houseplants are to thrive, water should be withheld from them during part of the year so that the plants go dormant.
Which one of the following is an assumption on which the argument depends?
(A) Most kinds of plants go dormant at some time or other during the year.
(B) Amaryllis are more difficult keep as houseplants than other kinds of plants are.
(C) Water should be withheld from amaryllis plants kept as houseplants during the exact time of year that corresponds to the dry season in their native habitat
(D) Any amaryllis plant that fails to thrive is likely to have been dormant for too short a time.
(E) Going dormant benefits amaryllis plants in their native habitat in some way other than simply preventing death during overly dry periods

Hi gmatmachoman!

Just say to yourself: "the evidence established that they go dormant in dry season."

But the conclusion is: "keep them dry to induce dormancy so that they thrive in the home."

Then analyze: "well in nature they will get dry for sure and that's why they go dormant (to protect against dryness). But he thinks making them go dormant is a good idea for the home too....he must be assuming that inducing dormancy will help in some way other than protecting against dryness."

Now we scan for a match, which is choice E

If you narrowed it down to D and E, you could have eliminated D on the basis of it being too extreme "any".

In assumption questions, the argument is unlikely to be so bold as to rely on an extreme assumption.

Is this argument so bold as to DEPEND on assuming that All plants that fail to thrive do so because of not being dormant long enough?

And, of course, you can also use denial test on E....

How would we use denial test here, gmatmachoman?

Hello Testluv,

Sorry but I am not able to understand why the answer is 'E'?

The explanation you have given is about what the person thinks about dormancy. E talks dormancy in their native environment.

Testluv wrote: (E) Going dormant benefits amaryllis plants in their native habitat in some way other than simply preventing death during overly dry periods

Then analyze: "well in nature they will get dry for sure and that's why they go dormant (to protect against dryness). But he thinks making them go dormant is a good idea for the home too....he must be assuming that inducing dormancy will help in some way other than protecting against dryness."

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mehravikas wrote:Hello Testluv,

Sorry but I am not able to understand why the answer is 'E'?

The explanation you have given is about what the person thinks about dormancy. E talks dormancy in their native environment.

Testluv wrote: (E) Going dormant benefits amaryllis plants in their native habitat in some way other than simply preventing death during overly dry periods

Then analyze: "well in nature they will get dry for sure and that's why they go dormant (to protect against dryness). But he thinks making them go dormant is a good idea for the home too....he must be assuming that inducing dormancy will help in some way other than protecting against dryness."

[/quote]

Hi vikas,

Well, they go dormant in nature to protect against dehydration. But there is no prospect of dehydration in the home since the home-owner can presumably water the plant whenever he chooses.

So, why the heck would he want to withhold water to indcue dormancy at the home? Why does he think that this is what must be done in order for the plant to thrive in the home?

He must be assuming that dormancy normally (ie, in nature) provides some benefit other than protection against dehydration. If this were not the case, then there is NO apparent beneficial reason to induce dormancy at home, and the argument falls apart.

What the author thinks about the function of dormancy of the plant in its natural environment is critical to his argument that we should induce dormancy at home.

i understood the arguement in the following way

In their native habitat, amaryllis plants go dormant during dry season. going dormant in that season helps them thrive (this is assumption). Hence if amaryllis plants kept as houseplants are to thrive, then they have to go dormant during that season.

hence the assumption is
going dormant causes them to thrive
i.e. dormant -> thrive
the author assumes that only going dormant in that season causes them to thrive. and when they go dormant in that season they will definately thrive.

ans (d) establishes that no dormant -> no thrive.
and hence is the correct answer.
Also the ans choice tell ANY amaryllis plant AND NOT All plants. hence i feel he is not extreme.

ans (e) tells that these plants will benifit something more apart from thriving.
Puttng this in our arguement doesnot make much sense.

In their native habitat, amaryllis plants go dormant during dry season. going dormant in that season benifits them apart from thriving (this is assumption). Hence if amaryllis plants kept as houseplants are to thrive, then they have to go dormant during that season.

Am i going wrong in my reasong?

Remember that Assumption is never stated in the argument. If it is stated, It is not an assumption but premise of the argument.

Assumption is always what you have to find out in an argument by observing the premise and the conclusion and how they are connected together.

Hi Raghav,
the sentence that i have marked as assumption is not there in the stimuli. i have added it to explain how that assumption links stimuli to the conclusion.

DeepakYakkundi wrote:i understood the arguement in the following way

In their native habitat, amaryllis plants go dormant during dry season. going dormant in that season helps them thrive (this is assumption). Hence if amaryllis plants kept as houseplants are to thrive, then they have to go dormant during that season.

hence the assumption is
going dormant causes them to thrive
i.e. dormant -> thrive
the author assumes that only going dormant in that season causes them to thrive. and when they go dormant in that season they will definately thrive.

ans (d) establishes that no dormant -> no thrive.
and hence is the correct answer.
Also the ans choice tell ANY amaryllis plant AND NOT All plants. hence i feel he is not extreme.

ans (e) tells that these plants will benifit something more apart from thriving.
Puttng this in our arguement doesnot make much sense.

In their native habitat, amaryllis plants go dormant during dry season. going dormant in that season benifits them apart from thriving (this is assumption). Hence if amaryllis plants kept as houseplants are to thrive, then they have to go dormant during that season.

Am i going wrong in my reasong?

Hi Deepak,

Actually, choice D does not establish "no dormant --> no thrive."

(D) Any amaryllis plant that fails to thrive is likely to have been dormant for too short a time.

In order for choice D to yield a definite conditional statement, it has to establish one of two things: a) that one condition is sufficient for another or b) that one condition is necessary for another.

"likely to have been" is not the same as "guaranteed to have been". Thus, sufficiency is not established. There is no language suggesting a relationship of necessity, so necessity is not established. There is no conditional statement.

If we replaced "likely to have been" with "guaranteed to have been", then the idea of the plants failing to thrive would be sufficient for establishing the idea that they had been dormant for too short a time, and the conditional statement would have been:

Fail to thrive-->not dormant long enough

And because formal logic is about the presence and absence of ideas, we would rewrite this as:

Not thriving-->Not dormant long enough.

I really wouldn't worry about this question. It is obviously an LSAT question testing loose formal logic and knowledge of formal logic conventions. In the OG 12, page 482, 5th paragraph, the test-maker explicitly states that it does not test knowledge of formal logic conventions.

Testluv wrote:

DeepakYakkundi wrote:i understood the arguement in the following way

In their native habitat, amaryllis plants go dormant during dry season. going dormant in that season helps them thrive (this is assumption). Hence if amaryllis plants kept as houseplants are to thrive, then they have to go dormant during that season.

hence the assumption is
going dormant causes them to thrive
i.e. dormant -> thrive
the author assumes that only going dormant in that season causes them to thrive. and when they go dormant in that season they will definately thrive.

ans (d) establishes that no dormant -> no thrive.
and hence is the correct answer.
Also the ans choice tell ANY amaryllis plant AND NOT All plants. hence i feel he is not extreme.

ans (e) tells that these plants will benifit something more apart from thriving.
Puttng this in our arguement doesnot make much sense.

In their native habitat, amaryllis plants go dormant during dry season. going dormant in that season benifits them apart from thriving (this is assumption). Hence if amaryllis plants kept as houseplants are to thrive, then they have to go dormant during that season.

Am i going wrong in my reasong?

Hi Deepak,

Actually, choice D does not establish "no dormant --> no thrive."

(D) Any amaryllis plant that fails to thrive is likely to have been dormant for too short a time.

In order for choice D to yield a definite conditional statement, it has to establish one of two things: a) that one condition is sufficient for another or b) that one condition is necessary for another.

"likely to have been" is not the same as "guaranteed to have been". Thus, sufficiency is not established. There is no language suggesting a relationship of necessity, so necessity is not established. There is no conditional statement.

If we replaced "likely to have been" with "guaranteed to have been", then the idea of the plants failing to thrive would be sufficient for establishing the idea that they had been dormant for too short a time, and the conditional statement would have been:

Fail to thrive-->not dormant long enough

And because formal logic is about the presence and absence of ideas, we would rewrite this as:

Not thriving-->Not dormant long enough.

I really wouldn't worry about this question. It is obviously an LSAT question testing loose formal logic and knowledge of formal logic conventions. In the OG 12, page 482, 5th paragraph, the test-maker explicitly states that it does not test knowledge of formal logic conventions.

Well, I have the following observation to make:

E - Speaks about some other benefit other than just surviving. Who knows about that? Where is it assumed that there can be another benefit without doing that? Where does it state that the plant's survival or routine goes fine without the dormancy period. In fact, it is explicitly mentioned that despite keeping in house, it needs to have that dormant phase.
Hence, clearly dormancy phase is required for survival or "thriving" at least. But, who knows/cares about "some other" benefiting some way?
A little far -fetched isn't it, especially, when both premises talk about dormancy periods, why do we have to question the purpose of periods.
Our job is to really compare the two scenarios in the two premises(Keeping in house and natural habitat).

Hence, C.

Well, about D, Premise says - "if amaryllis plants kept as houseplants are to thrive, water should be withheld from them during part of the year so that the plants go dormant"

Meaning, if withheld, then thrives.
If A, then B.
D clearly says - If not thriving, then likely to have too short dormancy. Again, how do we know?
If not B, then not A, is fine => Not thriving, then Not withheld from water(leave the other possibilities that might kill the plant - OOS).
But, how can we say, not withholding water => short or long dormant period????? This further assumes that longer the dormancy, better chance of thriving, again far-fetched, IMO.

Thanks,
Raghu

Hi Testluv, Please correct my reasoning here.