Q19 - Some species of tarantula make good pets

[ohthatpatrick]

Question Type:
Match the Reasoning

Stimulus Breakdown:
Conclusion: Some T's do not have poison fangs.
Evidence: Some T's make good pets, and nothing with poison fangs makes a good pet.

Answer Anticipation:
This is a perfectly valid inference.

We're given a conditional,
"If you're a good pet, you don't have poison fangs"
and a specific fact to apply it to,
"Some Tarantulas are good pets".

This lets us derive
"Some Tarantulas don't have poison fangs".

We can prephrase that we need an argument in which you're given two premises:
a conditional statement and a fact you can apply it to.

The conclusion should be the legal, derivable idea you get from applying the conditional statement.

If we want to get ourselves better ready for the specific quantified formula with which they presented this stuff, we need

(conditional premise): No P's are G.
(factual premise): Some T's are G.
============================
(conclusion): Not all T's are P.

Correct Answer:
A

Answer Choice Analysis:
(A) Looks good! We can apply the conditional to the fact to derive the conclusion.

(B) Nope, the two premise are both "some" statements. Not worth reading. We needed one conditional premise, one statement of fact.

(C) There is no way to apply the conditional in the 2nd sentence to the fact in the 1st sentence. No need to read further.

(D) There is no way to apply the conditional in the 2nd sentence to the fact in the 1st sentence. No need to read further.

(E) Two conditional premises? We just wanted one. We could stop reading at that point. If you were curious, this conclusion is not valid. The evidence tells us that "If you're in this collection, then you're not by Strawn and not regular meter." We can't derive the idea that "some of Strawn's poems do not have regular meter."

Takeaway/Pattern:
Some key conversions we should have memorized:
Not all A are B = Some A are not-B
.......No X are Y = All X are not-Y

#officialexplanation

[VidaH846]

I wonder is “some A are not C” the same with “some C are not A”？ This seems to me the difference between option A and C.

[SiddhantV399]

I took a ton of time on this question and could barely wrap my head around what was really going on. However, when I was reviewing it without any time constraints I came up with this solution which makes a lot of sense.

To analyze the argument and find the most similar pattern of reasoning, let's break down the original argument into its logical structure:

Premise 1: Some species of tarantula make good pets.
Premise 2: No creature with poison fangs makes a good pet.
Conclusion: Therefore, not all tarantula species have poison fangs.
This argument establishes a general statement about tarantulas as pets. It hypothesises that creatures with poison fangs cannot be good pets to conclude that not all tarantula species have poison fangs. The idea here is that we can use Premise 1 and Premise 2 combined to directly conclude the conclusion without any reasonable doubt.


Now let's analyse the Answer Choices:
A. None of the poetry written by Strawn has a regular meter. However, some of the poems in this collection have a regular meter. Therefore, at least some of the poems in this collection were not written by Strawn. Let's decode this:
Premise 1: None of the poetry written by Strawn has a regular meter.
Premise 2: However, some of the poems in this collection have a regular meter.
Given Conlusion: Therefore, at least some of the poems in this collection were not written by Strawn.

This argument says that none of Strawn's poetry has a regular meter and some poems in a collection do, concluding that some poems are not by Strawn. This is a direct application of contrasting properties (Strawn's poetry vs. the collection), similar in structure to the original argument. No reasonable doubt in the conclusion as well. Alright, A looks good.

B. Some of the poems in this collection have a regular meter. However, some of the poetry written by Strawn does not have a regular meter. Therefore, at least some of the poetry written by Strawn is not in this collection.

Premise 1: Some of the poems in this collection have a regular meter
Premise 2: However, some of the poetry written by Strawn does not have a regular meter.
Given Conlusion: Therefore, at least some of the poetry written by Strawn is not in this collection.

This states that some poems in a collection have a regular meter, while some of Strawn's poetry does not. It concludes that some of Strawn's poetry is not in the collection. First, there is no direct compatibility of a necessary condition here which makes the pattern less similar to the original pattern. So B is out.

C. Some of the poetry written by Strawn has a regular meter. However, this collection contains no poetry written by Strawn. Therefore, not all of the poetry in this collection has a regular meter.

Premise 1: Some of the poetry written by Strawn has a regular meter.
Premise 2: However, this collection contains no poetry written by Strawn.
Given Conlusion: Therefore, not all of the poetry in this collection has a regular meter.

This argues that some of Strawn's poetry has a regular meter, but this collection contains none of Strawn's poetry, concluding that not all poetry in the collection has a regular meter. This does not fit the pattern as it involves a negative inclusion rather than contrasting conditions. Hence we can rule out C.

D. Strawn wrote some of the poems in this collection. However, none of the poems in this collection have a regular meter. Therefore, only Strawn's unpublished poetry has a regular meter.

Premise 1: Strawn wrote some of the poems in this collection.
Premise 2: However, none of the poems in this collection have a regular meter.
Given Conlusion: Therefore, only Strawn's unpublished poetry has a regular meter.

This states that some poems are by Strawn and none in the collection has a regular meter, concluding about Strawn's unpublished work. This introduces unpublished poetry, which complicates the pattern compared to the original argument. Seems out of scope to talk about unpublished poetry when no premise directly points us to it. Nowhere close to the answer choice, D is out.

E. No poems with a regular meter are found in this collection and Strawn wrote none of the poetry in this collection. Therefore, not all of the poetry written by Strawn has a regular meter.

Premise 1: No poems with a regular meter are found in this collection
Premise 2: Strawn wrote none of the poetry in this collection
Given Conlusion: Therefore, not all of the poetry written by Strawn has a regular meter.

This states that no regular meter poems are in the collection, and none were written by Strawn, concluding about Strawn's overall poetry. This doesn't establish a clear connection or contrast similar to the original argument's reasoning. We can rule out E.

Conclusion:
The argument that most closely mirrors the pattern of reasoning in the original argument is:

A. None of the poetry written by Strawn has a regular meter. However, some of the poems in this collection have a regular meter. Therefore, at least some of the poems in this collection were not written by Strawn.

This choice parallels the structure of identifying a general attribute (no regular meter in Strawn's poetry) and contrasting it with a specific observation (some poems in the collection have a regular meter), leading to a similar exclusionary conclusion without a reasonable doubt.

Hope it helps someone who lands on this. One thing I did to make this process quicker is to analyse this using Venn diagrams. Of course, I have sketched them on a notebook and it's a pain to attach images on these forums so I couldn't add them, but it certainly helped me speed up the process of analysing the answer choices.