#8 - Astronomer: Conditions in our solar system have

[Administrator]

Please post your questions below!

[Juanq42]

Hi,

For being question #8, this one was especially challenging.

I was able to narrow it down to answer A and C because I identified that the stimulus contained only one conclusion (first sentence). However, I am having trouble recognizing the structure of the second sentence.

Since it mentions our sun later, i tried to re-read the Astronomer's argument with Earth in mind...

Astronomer claims that our solar system's conditions are more conducive to life than other solar systems of SIMILAR AGE. For example, the XYZ solar system of similar age, does not have conditions more conducive to life, while our solar system has Earth (full of life).

Earth's life depended on "adequate amounts of chemical elements heavier than hydrogen and helium." So, in order for Earth to have life, it required some undetermined amount of these chemicals. At the very least, it needed some amount.

Our sun has "an unusually high abundance of hydrogen and helium for its age." I read this, and consider, okay, when compared to the hypothetical XYZ solar system of similar age, Earth happens to have way more of these chemicals.

I read answer A now and think it is trying to say:
the lack of evidence that XYZ solar system has less hydrogen and helium, functions as evidence to the astronomers' conclusion - that the unusually high abundance of hydrogen and helium (while not proven) is PROBABLY the reason why our solar system has life on Earth.

Is this why answer A is correct?

[James Finch]

Hi Juan,

(A) is describing a premise, full stop, while (C) is describing an intermediate conclusion. As both can play the role of premise to the main conclusion, the question then becomes whether or not there is a premise supporting the particular statement in question. Here, the statement is conditional, life adequate amounts, and conditional statement tend to be premises on the LSAT. The big key, however, is that the other premise is just stating that the necessary condition of the conditional statement is true for our solar system. which does nothing to support the conditional statement itself being true. As there's nothing else in the stimulus aside from the conclusion, the conditional statement can only be a premise, not an intermediate conclusion.

Hope this clears things up!

[ser219]

I originally picked B. Could someone explain why it is wrong? I thought maybe the statement could be counted as support for the statement that our has an unusually high abundance.

[Jeremy Press]

Hi ser,

The problem with answer choice B is that the claim in the question stem cannot be read as part of the support for the last statement in the stimulus. Think of it this way: why does our sun have an unusually high abundance of heavier elements? There could be lots of reasons, I suppose, but I don't think any of them has to do with what the conceivable forms of life depend on. In other words, the sun's condition doesn't depend on what life needs.

Also, there is a structural clue that the author doesn't intend the claim in the question stem to be construed as direct support for the claim about the sun's high abundance of heavier elements. What is that clue? The two claims are joined by the term "and," thus indicating that each serves as its own independent support for the first sentence. Had the author meant the two claims to be construed as logically related, the author likely would've used a conjunction like "hence," "therefore," "thus," "as a result," etc.

I hope this helps!

Jeremy

[April30Gang]

Changing words here to avoid c***right.

"Any perceptible form of life depends on chemical elements heavier than H."

"Our sun has an unusually high abundance of these heavier elements for its age."

The middle sentence seems supported tho, no?

Any famous actor depends on their box office sales to work.

Meryl Streep (who we know is famous, just like we know the sun is in our solar system) depends on her box office numbers to work.

What am I missing here?

The 3rd sentence seems like an example that strengthens the middle sentence. The middle sentence makes a broad conditional claim and the 3rd sentence fits the claim.

I was on the fence about C but it seemed like the best answer there. If C had said "some support" instead of "Evidence" will it be a contender?

What will an example of evidence look like? Something explicit like "the life on earth would diminish when it begins to experience below adequate levels of hydrogen and helium?" Help me

Would you consider this for A if its was the third sentence?
"The conceivable life under our sun emerged because adequate amounts of hydrogen and helium were present?

[katehos]

Hi April,

The third sentence about the sun, while it supports the conclusion as a whole, does not provide evidence for the claim about any conceivable lifeforms. Rather, it supports the idea that conditions in our solar system probably favored life (because, if life depends on heavier chemicals, and the sun happens to have them, then it makes it more likely that our solar system has favorable conditions for life).

Try to think about it this way: does the sun having heavier elements support the claim that life depends on heavier elements? Not really, something that would actually support this claim could be scientific data that actually proves such elements are necessary for life to emerge (perhaps a series of experiments meant to replicate the formation of life or observations on other planets). But the author does not provide such evidence, so the claim in the question stem is not supported by evidence (and we can eliminate answer choice (C)), but it is a premise used to support the argument's conclusion (which leads us to choice (A)).

Understanding this relationship is key to helping answer your other questions, because changing "some evidence" to "some support" still does not make the statement about the sun prove that the statement about life depending on heavier elements true. Together, the statements support the conclusion; but alone, they do not support one another. Your alternate example for the third sentence does do a better job of providing evidence for the claim about conceivable life than the stimulus currently provides - good thinking! If the stimulus said something along the lines of "...heavier than hydrogen and helium, which has been demonstrated by [studies/experiments] that prove life under our sun emerged because of the amount of chemicals heavier than..." we might not eliminate (C) so quickly.

Hope this helps!
Kate

[dtbthree]

In isolation, I can understand the correct answer here. However, when I take into consideration question 20 from this section, I don't understand. The two questions seem very similar to me, yet have different answers.

Question 8:
Premise 1: Any conceivable form of life depends on the presence of adequate amounts of chemical elements heavier than hydrogen and helium.
Premise 2: Our sun has an unusually high abundance of these heavier elements for its age.
Conclusion: Our solar system favored the emergence of life more than others.

Question 20:
Premise 1: Many local business depend on region's natural beauty
Subconclusion: Heavy industrial activity of coal mining would force most of them to close
Conclusion: Coal mining will actually lead to decreased number of jobs

It seems like in each instance the first premise performs nearly an identical role. It provides support to next sentence that provides support for the conclusion. In both question if you remove the first premise the remaining sentence does not make sense or adequately support the conclusion. Further, in both questions the first premise cannot alone be used to support the conclusion. What are the differences between these two questions? Specifically, could you please explain how both of the first premises perform different roles?

Thank you so much in advance!

[Jeff Wren]

Hi dtbthree,

While these two arguments may seem similar, there is a key difference between how the logic flows in each argument that can be tricky to distinguish.

In question 8, the first sentence doesn't actually support the second premise. They are completely separate but related, and the two together support the conclusion.

The second premise (the fact that our sun has an unusually high abundance of these heavier elements) is just a fact that is taken as give (i.e. a premise). It does not depend on the first premise at all. In other words, it's not because life depends on these heavier elements that the sun has them.

Here's another argument to illustrate.

Premise 1: Anyone who has a Twix has a candy bar.
Premise 2: John has a Twix.
Conclusion: Therefore John has a candy bar.

In this argument, the fact that John has a Twix is not because of the first premise. Like the argument in question 8, the two independent premises work together to prove the conclusion.

In question 20, on the other hand, the statement that heavy industrial activity of coal mining would force most of the local businesses to close does follow from the premise that many of the local businesses depend on the region's natural beauty (along with the unstated premise a.k.a. the assumption that coal mines will destroy the natural beauty).

The fact that the argument in question 20 does require an assumption for it to make sense does make it more difficult.

If we add in the assumption, it is easier to see how the logic flows.

Premise 1: Many local business depend on the region's natural beauty.
Assumption: The coal mines will destroy the region's natural beauty.
Subconclusion: Therefore, heavy industrial activity of coal mining would force most of these local businesses to close.
Conclusion: Therefore, coal mining will actually lead to decreased number of jobs.